Quelle lib.rs

Sprache: Rust

//! Module for parsing ISO Base Media Format aka video/mp4 streams.

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

// `clippy::upper_case_acronyms` is a nightly-only lint as of 2021-03-15, so we
// allow `clippy::unknown_clippy_lints` to ignore it on stable - but
// `clippy::unknown_clippy_lints` has been renamed in nightly, so we need to
// allow `renamed_and_removed_lints` to ignore a warning for that.
#![allow(renamed_and_removed_lints)]
#![allow(clippy::unknown_clippy_lints)]
#![allow(clippy::upper_case_acronyms)]

#[macro_use]
extern crate log;

extern crate bitreader;
extern crate byteorder;
extern crate fallible_collections;
extern crate num_traits;
use bitreader::{BitReader, ReadInto};
use byteorder::{ReadBytesExt, WriteBytesExt};

use fallible_collections::TryRead;
use fallible_collections::TryReserveError;

use num_traits::Num;
use std::convert::{TryFrom, TryInto as _};
use std::fmt;
use std::io::Cursor;
use std::io::{Read, Take};

#[macro_use]
mod macros;

mod boxes;
use crate::boxes::{BoxType, FourCC};

// Unit tests.
#[cfg(test)]
mod tests;

#[cfg(feature = "unstable-api")]
pub mod unstable;

/// The HEIF image and image collection brand
/// The 'mif1' brand indicates structural requirements on files
/// See HEIF (ISO 23008-12:2017) § 10.2.1
pub const MIF1_BRAND: FourCC = FourCC { value: *b"mif1" };

/// The HEIF image sequence brand
/// The 'msf1' brand indicates structural requirements on files
/// See HEIF (ISO 23008-12:2017) § 10.3.1
pub const MSF1_BRAND: FourCC = FourCC { value: *b"msf1" };

/// The brand to identify AV1 image items
/// The 'avif' brand indicates structural requirements on files
/// See <https://aomediacodec.github.io/av1-avif/#image-and-image-collection-brand>
pub const AVIF_BRAND: FourCC = FourCC { value: *b"avif" };

/// The brand to identify AVIF image sequences
/// The 'avis' brand indicates structural requirements on files
/// See <https://aomediacodec.github.io/av1-avif/#image-and-image-collection-brand>
pub const AVIS_BRAND: FourCC = FourCC { value: *b"avis" };

/// A trait to indicate a type can be infallibly converted to `u64`.
/// This should only be implemented for infallible conversions, so only unsigned types are valid.
trait ToU64 {
 fn to_u64(self) -> u64;
}

/// Statically verify that the platform `usize` can fit within a `u64`.
/// If the size won't fit on the given platform, this will fail at compile time, but if a type
/// which can fail `TryInto<usize>` is used, it may panic.
impl ToU64 for usize {
 fn to_u64(self) -> u64 {
 static_assertions::const_assert!(
 std::mem::size_of::<usize>() <= std::mem::size_of::<u64>()
 );
 self.try_into().expect("usize -> u64 conversion failed")
 }
}

/// A trait to indicate a type can be infallibly converted to `usize`.
/// This should only be implemented for infallible conversions, so only unsigned types are valid.
pub trait ToUsize {
 fn to_usize(self) -> usize;
}

/// Statically verify that the given type can fit within a `usize`.
/// If the size won't fit on the given platform, this will fail at compile time, but if a type
/// which can fail `TryInto<usize>` is used, it may panic.
macro_rules! impl_to_usize_from {
 ( $from_type:ty ) => {
 impl ToUsize for $from_type {
 fn to_usize(self) -> usize {
 static_assertions::const_assert!(
 std::mem::size_of::<$from_type>() <= std::mem::size_of::<usize>()
 );
 self.try_into().expect(concat!(
 stringify!($from_type),
 " -> usize conversion failed"
 ))
 }
 }
 };
}

impl_to_usize_from!(u8);
impl_to_usize_from!(u16);
impl_to_usize_from!(u32);

/// Indicate the current offset (i.e., bytes already read) in a reader
trait Offset {
 fn offset(&self) -> u64;
}

/// Wraps a reader to track the current offset
struct OffsetReader<'a, T: 'a> {
 reader: &'a mut T,
 offset: u64,
}

impl<'a, T> OffsetReader<'a, T> {
 fn new(reader: &'a mut T) -> Self {
 Self { reader, offset: 0 }
 }
}

impl<'a, T> Offset for OffsetReader<'a, T> {
 fn offset(&self) -> u64 {
 self.offset
 }
}

impl<'a, T: Read> Read for OffsetReader<'a, T> {
 fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
 let bytes_read = self.reader.read(buf)?;
 trace!("Read {} bytes at offset {}", bytes_read, self.offset);
 self.offset = self
 .offset
 .checked_add(bytes_read.to_u64())
 .expect("total bytes read too large for offset type");
 Ok(bytes_read)
 }
}

pub type TryVec<T> = fallible_collections::TryVec<T>;
pub type TryString = fallible_collections::TryVec<u8>;
pub type TryHashMap<K, V> = fallible_collections::TryHashMap<K, V>;
pub type TryBox<T> = fallible_collections::TryBox<T>;

// To ensure we don't use stdlib allocating types by accident
#[allow(dead_code)]
struct Vec;
#[allow(dead_code)]
struct Box;
#[allow(dead_code)]
struct HashMap;
#[allow(dead_code)]
struct String;

/// The return value to the C API
/// Any detail that needs to be communicated to the caller must be encoded here
/// since the [`Error`] type's associated data is part of the FFI.
#[repr(C)]
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum Status {
 Ok = 0,
 BadArg = 1,
 Invalid = 2,
 Unsupported = 3,
 Eof = 4,
 Io = 5,
 Oom = 6,
 A1lxEssential,
 A1opNoEssential,
 AlacBadMagicCookieSize,
 AlacFlagsNonzero,
 Av1cMissing,
 BitReaderError,
 BoxBadSize,
 BoxBadWideSize,
 CheckParserStateErr,
 ColrBadQuantity,
 ColrBadSize,
 ColrBadType,
 ColrReservedNonzero,
 ConstructionMethod,
 CttsBadSize,
 CttsBadVersion,
 DflaBadMetadataBlockSize,
 DflaFlagsNonzero,
 DflaMissingMetadata,
 DflaStreamInfoBadSize,
 DflaStreamInfoNotFirst,
 DopsChannelMappingWriteErr,
 DopsOpusHeadWriteErr,
 ElstBadVersion,
 EsdsBadAudioSampleEntry,
 EsdsBadDescriptor,
 EsdsDecSpecificIntoTagQuantity,
 FtypBadSize,
 FtypNotFirst,
 HdlrNameNoNul,
 HdlrNameNotUtf8,
 HdlrNotFirst,
 HdlrPredefinedNonzero,
 HdlrReservedNonzero,
 HdlrTypeNotPict,
 HdlrUnsupportedVersion,
 HdrlBadQuantity,
 IdatBadQuantity,
 IdatMissing,
 IinfBadChild,
 IinfBadQuantity,
 IlocBadConstructionMethod,
 IlocBadExtent,
 IlocBadExtentCount,
 IlocBadFieldSize,
 IlocBadQuantity,
 IlocBadSize,
 IlocDuplicateItemId,
 IlocNotFound,
 IlocOffsetOverflow,
 ImageItemType,
 InfeFlagsNonzero,
 InvalidUtf8,
 IpcoIndexOverflow,
 IpmaBadIndex,
 IpmaBadItemOrder,
 IpmaBadQuantity,
 IpmaBadVersion,
 IpmaDuplicateItemId,
 IpmaFlagsNonzero,
 IpmaIndexZeroNoEssential,
 IpmaTooBig,
 IpmaTooSmall,
 IprpBadChild,
 IprpBadQuantity,
 IprpConflict,
 IrefBadQuantity,
 IrefRecursion,
 IspeMissing,
 ItemTypeMissing,
 LselNoEssential,
 MdhdBadTimescale,
 MdhdBadVersion,
 MehdBadVersion,
 MetaBadQuantity,
 MissingAvifOrAvisBrand,
 MissingMif1Brand,
 MoovBadQuantity,
 MoovMissing,
 MultipleAlpha,
 MvhdBadTimescale,
 MvhdBadVersion,
 NoImage,
 PitmBadQuantity,
 PitmMissing,
 PitmNotFound,
 PixiBadChannelCount,
 PixiMissing,
 PsshSizeOverflow,
 ReadBufErr,
 SchiQuantity,
 StsdBadAudioSampleEntry,
 StsdBadVideoSampleEntry,
 TkhdBadVersion,
 TxformBeforeIspe,
 TxformNoEssential,
 TxformOrder,
}

#[repr(C)]
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum Feature {
 A1lx,
 A1op,
 Auxc,
 Av1c,
 Avis,
 Clap,
 Colr,
 Grid,
 Imir,
 Ipro,
 Irot,
 Ispe,
 Lsel,
 Pasp,
 Pixi,
}

impl Feature {
 fn supported(self) -> bool {
 match self {
 Self::Auxc
 | Self::Av1c
 | Self::Avis
 | Self::Colr
 | Self::Imir
 | Self::Irot
 | Self::Ispe
 | Self::Pasp
 | Self::Pixi => true,
 Self::A1lx | Self::A1op | Self::Clap | Self::Grid | Self::Ipro | Self::Lsel => false,
 }
 }
}

impl TryFrom<&ItemProperty> for Feature {
 type Error = Error;

 fn try_from(item_property: &ItemProperty) -> Result<Self, Self::Error> {
 Ok(match item_property {
 ItemProperty::AuxiliaryType(_) => Self::Auxc,
 ItemProperty::AV1Config(_) => Self::Av1c,
 ItemProperty::Channels(_) => Self::Pixi,
 ItemProperty::CleanAperture => Self::Clap,
 ItemProperty::Colour(_) => Self::Colr,
 ItemProperty::ImageSpatialExtents(_) => Self::Ispe,
 ItemProperty::LayeredImageIndexing => Self::A1lx,
 ItemProperty::LayerSelection => Self::Lsel,
 ItemProperty::Mirroring(_) => Self::Imir,
 ItemProperty::OperatingPointSelector => Self::A1op,
 ItemProperty::PixelAspectRatio(_) => Self::Pasp,
 ItemProperty::Rotation(_) => Self::Irot,
 item_property => {
 error!("No known Feature variant for {:?}", item_property);
 return Err(Error::Unsupported("missing Feature fox ItemProperty"));
 }
 })
 }
}

/// A collection to indicate unsupported features that were encountered during
/// parsing. Since the default behavior for many such features is to ignore
/// them, this often not fatal and there may be several to report.
#[derive(Debug, Default)]
pub struct UnsupportedFeatures(u32);

impl UnsupportedFeatures {
 pub fn new() -> Self {
 Self(0x0)
 }

 pub fn into_bitfield(&self) -> u32 {
 self.0
 }

 fn feature_to_bitfield(feature: Feature) -> u32 {
 let index = feature as usize;
 assert!(
 u8::BITS.to_usize() * std::mem::size_of::<Self>() > index,
 "You're gonna need a bigger bitfield"
 );
 let bitfield = 1u32 << index;
 assert_eq!(bitfield.count_ones(), 1);
 bitfield
 }

 pub fn insert(&mut self, feature: Feature) {
 warn!("Unsupported feature: {:?}", feature);
 self.0 |= Self::feature_to_bitfield(feature);
 }

 pub fn contains(&self, feature: Feature) -> bool {
 self.0 & Self::feature_to_bitfield(feature) != 0x0
 }

 pub fn is_empty(&self) -> bool {
 self.0 == 0x0
 }
}

impl<T> From<Status> for Result<T> {
 /// A convenience method to enable shortcuts like
 /// ```
 /// # use mp4parse::{Result,Status};
 /// # let _: Result<()> =
 /// Status::MissingAvifOrAvisBrand.into();
 /// ```
 /// instead of
 /// ```
 /// # use mp4parse::{Error,Result,Status};
 /// # let _: Result<()> =
 /// Err(Error::from(Status::MissingAvifOrAvisBrand));
 /// ```
 /// Note that `Status::Ok` can't be supported this way and will panic.
 fn from(parse_status: Status) -> Self {
 match parse_status {
 Status::Ok => panic!("Can't determine Ok(_) inner value from Status"),
 err_status => Err(err_status.into()),
 }
 }
}

/// For convenience of creating an error for an unsupported feature which we
/// want to communicate the specific feature back to the C API caller
impl From<Status> for Error {
 fn from(parse_status: Status) -> Self {
 match parse_status {
 Status::Ok
 | Status::BadArg
 | Status::Invalid
 | Status::Unsupported
 | Status::Eof
 | Status::Io
 | Status::Oom => {
 panic!("Status -> Error is only for Status:InvalidData errors")
 }
 _ => Self::InvalidData(parse_status),
 }
 }
}

impl From<Status> for &str {
 fn from(status: Status) -> Self {
 match status {
 Status::Ok
 | Status::BadArg
 | Status::Invalid
 | Status::Unsupported
 | Status::Eof
 | Status::Io
 | Status::Oom => {
 panic!("Status -> Error is only for specific parsing errors")
 }
 Status::A1lxEssential => {
 "AV1LayeredImageIndexingProperty (a1lx) shall not be marked as essential \
 per https://aomediacodec.github.io/av1-avif/#layered-image-indexing-property-description"
 }
 Status::A1opNoEssential => {
 "OperatingPointSelectorProperty (a1op) shall be marked as essential \
 per https://aomediacodec.github.io/av1-avif/#operating-point-selector-property-description"
 }
 Status::AlacBadMagicCookieSize => {
 "ALACSpecificBox magic cookie is the wrong size"
 }
 Status::AlacFlagsNonzero => {
 "no-zero alac (ALAC) flags"
 }
 Status::Av1cMissing => {
 "One AV1 Item Configuration Property (av1C) is mandatory for an \
 image item of type 'av01' \
 per AVIF specification § 2.2.1"
 }
 Status::BitReaderError => {
 "Bitwise read failed"
 }
 Status::BoxBadSize => {
 "malformed size"
 }
 Status::BoxBadWideSize => {
 "malformed wide size"
 }
 Status::CheckParserStateErr => {
 "unread box content or bad parser sync"
 }
 Status::ColrBadQuantity => {
 "Each item shall have at most one property association with a
 ColourInformationBox (colr) for a given value of colour_type \
 per HEIF (ISO/IEC DIS 23008-12) § 6.5.5.1"
 }
 Status::ColrBadSize => {
 "Unexpected size for colr box"
 }
 Status::ColrBadType => {
 "Unsupported colour_type for ColourInformationBox"
 }
 Status::ColrReservedNonzero => {
 "The 7 reserved bits at the end of the ColourInformationBox \
 for colour_type == 'nclx' must be 0 \
 per ISOBMFF (ISO 14496-12:2020) § 12.1.5.2"
 }
 Status::ConstructionMethod => {
 "construction_method shall be 0 (file) or 1 (idat) per MIAF (ISO 23000-22:2019) § 7.2.1.7"
 }
 Status::CttsBadSize => {
 "insufficient data in 'ctts' box"
 }
 Status::CttsBadVersion => {
 "unsupported version in 'ctts' box"
 }
 Status::DflaBadMetadataBlockSize => {
 "FLACMetadataBlock larger than parent box"
 }
 Status::DflaFlagsNonzero => {
 "no-zero dfLa (FLAC) flags"
 }
 Status::DflaMissingMetadata => {
 "FLACSpecificBox missing metadata"
 }
 Status::DflaStreamInfoBadSize => {
 "FLACSpecificBox STREAMINFO block is the wrong size"
 }
 Status::DflaStreamInfoNotFirst => {
 "FLACSpecificBox must have STREAMINFO metadata first"
 }
 Status::DopsChannelMappingWriteErr => {
 "Couldn't write channel mapping table data."
 }
 Status::DopsOpusHeadWriteErr => {
 "Couldn't write OpusHead tag."
 }
 Status::ElstBadVersion => {
 "unhandled elst version"
 }
 Status::EsdsBadAudioSampleEntry => {
 "malformed audio sample entry"
 }
 Status::EsdsBadDescriptor => {
 "Invalid descriptor."
 }
 Status::EsdsDecSpecificIntoTagQuantity => {
 "There can be only one DecSpecificInfoTag descriptor"
 }
 Status::FtypBadSize => {
 "invalid ftyp size"
 }
 Status::FtypNotFirst => {
 "The FileTypeBox shall be placed as early as possible in the file \
 per ISOBMFF (ISO 14496-12:2020) § 4.3.1"
 }
 Status::HdlrNameNoNul => {
 "The HandlerBox 'name' field shall be null-terminated \
 per ISOBMFF (ISO 14496-12:2020) § 8.4.3.2"
 }
 Status::HdlrNameNotUtf8 => {
 "The HandlerBox 'name' field shall be valid utf8 \
 per ISOBMFF (ISO 14496-12:2020) § 8.4.3.2"
 }
 Status::HdlrNotFirst => {
 "The HandlerBox shall be the first contained box within the MetaBox \
 per MIAF (ISO 23000-22:2019) § 7.2.1.5"
 }
 Status::HdlrPredefinedNonzero => {
 "The HandlerBox 'pre_defined' field shall be 0 \
 per ISOBMFF (ISO 14496-12:2020) § 8.4.3.2"
 }
 Status::HdlrReservedNonzero => {
 "The HandlerBox 'reserved' fields shall be 0 \
 per ISOBMFF (ISO 14496-12:2020) § 8.4.3.2"
 }
 Status::HdlrTypeNotPict => {
 "The HandlerBox handler_type must be 'pict' \
 per MIAF (ISO 23000-22:2019) § 7.2.1.5"
 }
 Status::HdlrUnsupportedVersion => {
 "The HandlerBox version shall be 0 (zero) \
 per ISOBMFF (ISO 14496-12:2020) § 8.4.3.2"
 }
 Status::HdrlBadQuantity => {
 "There shall be exactly one hdlr box \
 per ISOBMFF (ISO 14496-12:2020) § 8.4.3.1"
 }
 Status::IdatBadQuantity => {
 "There shall be zero or one idat boxes \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.11"
 }
 Status::IdatMissing => {
 "ItemLocationBox (iloc) construction_method indicates 1 (idat), \
 but no idat box is present."
 }
 Status::IinfBadChild => {
 "iinf box shall contain only infe boxes \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.6.2"
 }
 Status::IinfBadQuantity => {
 "There shall be zero or one iinf boxes \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.6.1"
 }
 Status::IlocBadConstructionMethod => {
 "construction_method is taken from the set 0, 1 or 2 \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.3.3"
 }
 Status::IlocBadExtent => {
 "extent_count != 1 requires explicit offset and length \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.3.3"
 }
 Status::IlocBadExtentCount => {
 "extent_count must have a value 1 or greater \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.3.3"
 }
 Status::IlocBadFieldSize => {
 "value must be in the set {0, 4, 8}"
 }
 Status::IlocBadQuantity => {
 "There shall be zero or one iloc boxes \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.3.1"
 }
 Status::IlocBadSize => {
 "invalid iloc size"
 }
 Status::IlocDuplicateItemId => {
 "duplicate item_ID in iloc"
 }
 Status::IlocNotFound => {
 "ItemLocationBox (iloc) contains an extent not present in any mdat or idat box"
 }
 Status::IlocOffsetOverflow => {
 "offset calculation overflow"
 }
 Status::ImageItemType => {
 "Image item type is neither 'av01' nor 'grid'"
 }
 Status::InfeFlagsNonzero => {
 "'infe' flags field shall be 0 \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.6.2"
 }
 Status::InvalidUtf8 => {
 "invalid utf8"
 }
 Status::IpcoIndexOverflow => {
 "ipco index overflow"
 }
 Status::IpmaBadIndex => {
 "Invalid property index in ipma"
 }
 Status::IpmaBadItemOrder => {
 "Each ItemPropertyAssociation box shall be ordered by increasing item_ID"
 }
 Status::IpmaBadQuantity => {
 "There shall be at most one ItemPropertyAssociationbox with a given pair of \
 values of version and flags \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.14.1"
 }
 Status::IpmaBadVersion => {
 "The ipma version 0 should be used unless 32-bit item_ID values are needed \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.14.1"
 }
 Status::IpmaDuplicateItemId => {
 "There shall be at most one occurrence of a given item_ID, \
 in the set of ItemPropertyAssociationBox boxes \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.14.1"
 }
 Status::IpmaFlagsNonzero => {
 "Unless there are more than 127 properties in the ItemPropertyContainerBox, \
 flags should be equal to 0 \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.14.1"
 }
 Status::IpmaIndexZeroNoEssential => {
 "the essential indicator shall be 0 for property index 0 \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.14.3"
 }
 Status::IpmaTooBig => {
 "ipma box exceeds maximum size for entry_count"
 }
 Status::IpmaTooSmall => {
 "ipma box below minimum size for entry_count"
 }
 Status::IprpBadChild => {
 "unexpected iprp child"
 }
 Status::IprpBadQuantity => {
 "There shall be zero or one iprp boxes \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.14.1"
 }
 Status::IprpConflict => {
 "conflicting item property values"
 }
 Status::IrefBadQuantity => {
 "There shall be zero or one iref boxes \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.12.1"
 }
 Status::IrefRecursion => {
 "from_item_id and to_item_id must be different"
 }
 Status::IspeMissing => {
 "Missing 'ispe' property for image item, required \
 per HEIF (ISO/IEC 23008-12:2017) § 6.5.3.1"
 }
 Status::ItemTypeMissing => {
 "No ItemInfoEntry for item_ID"
 }
 Status::LselNoEssential => {
 "LayerSelectorProperty (lsel) shall be marked as essential \
 per HEIF (ISO/IEC 23008-12:2017) § 6.5.11.1"
 }
 Status::MdhdBadTimescale => {
 "zero timescale in mdhd"
 }
 Status::MdhdBadVersion => {
 "unhandled mdhd version"
 }
 Status::MehdBadVersion => {
 "unhandled mehd version"
 }
 Status::MetaBadQuantity => {
 "There should be zero or one meta boxes \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.1.1"
 }
 Status::MissingAvifOrAvisBrand => {
 "The file shall list 'avif' or 'avis' in the compatible_brands field
 of the FileTypeBox \
 per https://aomediacodec.github.io/av1-avif/#file-constraints"
 }
 Status::MissingMif1Brand => {
 "The FileTypeBox should contain 'mif1' in the compatible_brands list \
 per MIAF (ISO 23000-22:2019/Amd. 2:2021) § 7.2.1.2"
 }
 Status::MoovBadQuantity => {
 "Multiple moov boxes found; \
 files with avis or msf1 brands shall contain exactly one moov box \
 per ISOBMFF (ISO 14496-12:2020) § 8.2.1.1"
 }
 Status::MoovMissing => {
 "No moov box found; \
 files with avis or msf1 brands shall contain exactly one moov box \
 per ISOBMFF (ISO 14496-12:2020) § 8.2.1.1"
 }
 Status::MultipleAlpha => {
 "multiple alpha planes"
 }
 Status::MvhdBadTimescale => {
 "zero timescale in mvhd"
 }
 Status::MvhdBadVersion => {
 "unhandled mvhd version"
 }
 Status::NoImage => "No primary image or image sequence found",
 Status::PitmBadQuantity => {
 "There shall be zero or one pitm boxes \
 per ISOBMFF (ISO 14496-12:2020) § 8.11.4.1"
 }
 Status::PitmMissing => {
 "Missing required PrimaryItemBox (pitm), required \
 per HEIF (ISO/IEC 23008-12:2017) § 10.2.1"
 }
 Status::PitmNotFound => {
 "PrimaryItemBox (pitm) referenced an item ID that was not present"
 }
 Status::PixiBadChannelCount => {
 "invalid num_channels"
 }
 Status::PixiMissing => {
 "The pixel information property shall be associated with every image \
 that is displayable (not hidden) \
 per MIAF (ISO/IEC 23000-22:2019) specification § 7.3.6.6"
 }
 Status::PsshSizeOverflow => {
 "overflow in read_pssh"
 }
 Status::ReadBufErr => {
 "failed buffer read"
 }
 Status::SchiQuantity => {
 "tenc box should be only one at most in sinf box"
 }
 Status::StsdBadAudioSampleEntry => {
 "malformed audio sample entry"
 }
 Status::StsdBadVideoSampleEntry => {
 "malformed video sample entry"
 }
 Status::TkhdBadVersion => {
 "unhandled tkhd version"
 }
 Status::TxformBeforeIspe => {
 "Every image item shall be associated with one property of \
 type ImageSpatialExtentsProperty (ispe), prior to the \
 association of all transformative properties. \
 per HEIF (ISO/IEC 23008-12:2017) § 6.5.3.1"
 }
 Status::TxformNoEssential => {
 "All transformative properties associated with coded and \
 derived images required or conditionally required by this \
 document shall be marked as essential \
 per MIAF (ISO 23000-22:2019) § 7.3.9"
 }
 Status::TxformOrder => {
 "These properties, if used, shall be indicated to be applied \
 in the following order: clean aperture first, then rotation, \
 then mirror. \
 per MIAF (ISO/IEC 23000-22:2019) § 7.3.6.7"
 }
 }
 }
}

impl From<Error> for Status {
 fn from(error: Error) -> Self {
 match error {
 Error::Unsupported(_) => Self::Unsupported,
 Error::InvalidData(parse_status) => parse_status,
 Error::UnexpectedEOF => Self::Eof,
 Error::Io(_) => {
 // Getting std::io::ErrorKind::UnexpectedEof is normal
 // but our From trait implementation should have converted
 // those to our Error::UnexpectedEOF variant.
 Self::Io
 }
 Error::MoovMissing => Self::MoovMissing,
 Error::OutOfMemory => Self::Oom,
 }
 }
}

impl From<Result<(), Status>> for Status {
 fn from(result: Result<(), Status>) -> Self {
 match result {
 Ok(()) => Status::Ok,
 Err(Status::Ok) => unreachable!(),
 Err(e) => e,
 }
 }
}

impl<T> From<Result<T>> for Status {
 fn from(result: Result<T>) -> Self {
 match result {
 Ok(_) => Status::Ok,
 Err(e) => Status::from(e),
 }
 }
}

impl From<fallible_collections::TryReserveError> for Status {
 fn from(_: fallible_collections::TryReserveError) -> Self {
 Status::Oom
 }
}

impl From<std::io::Error> for Status {
 fn from(_: std::io::Error) -> Self {
 Status::Io
 }
}

/// Describes parser failures.
///
/// This enum wraps the standard `io::Error` type, unified with
/// our own parser error states and those of crates we use.
#[derive(Debug)]
pub enum Error {
 /// Parse error caused by corrupt or malformed data.
 /// See the helper [`From<Status> for Error`](enum.Error.html#impl-From<Status>)
 InvalidData(Status),
 /// Parse error caused by limited parser support rather than invalid data.
 Unsupported(&'static str),
 /// Reflect `std::io::ErrorKind::UnexpectedEof` for short data.
 UnexpectedEOF,
 /// Propagate underlying errors from `std::io`.
 Io(std::io::Error),
 /// read_mp4 terminated without detecting a moov box.
 MoovMissing,
 /// Out of memory
 OutOfMemory,
}

impl std::fmt::Display for Error {
 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 write!(f, "{self:?}")
 }
}

impl std::error::Error for Error {}

impl From<bitreader::BitReaderError> for Error {
 fn from(_: bitreader::BitReaderError) -> Error {
 Status::BitReaderError.into()
 }
}

impl From<std::io::Error> for Error {
 fn from(err: std::io::Error) -> Error {
 match err.kind() {
 std::io::ErrorKind::UnexpectedEof => Error::UnexpectedEOF,
 _ => Error::Io(err),
 }
 }
}

impl From<std::string::FromUtf8Error> for Error {
 fn from(_: std::string::FromUtf8Error) -> Error {
 Status::InvalidUtf8.into()
 }
}

impl From<std::str::Utf8Error> for Error {
 fn from(_: std::str::Utf8Error) -> Error {
 Status::InvalidUtf8.into()
 }
}

impl From<std::num::TryFromIntError> for Error {
 fn from(_: std::num::TryFromIntError) -> Error {
 Error::Unsupported("integer conversion failed")
 }
}

impl From<Error> for std::io::Error {
 fn from(err: Error) -> Self {
 let kind = match err {
 Error::UnexpectedEOF => std::io::ErrorKind::UnexpectedEof,
 Error::Io(io_err) => return io_err,
 _ => std::io::ErrorKind::Other,
 };
 Self::new(kind, err)
 }
}

impl From<TryReserveError> for Error {
 fn from(_: TryReserveError) -> Error {
 Error::OutOfMemory
 }
}

/// Result shorthand using our Error enum.
pub type Result<T, E = Error> = std::result::Result<T, E>;

/// Basic ISO box structure.
///
/// mp4 files are a sequence of possibly-nested 'box' structures. Each box
/// begins with a header describing the length of the box's data and a
/// four-byte box type which identifies the type of the box. Together these
/// are enough to interpret the contents of that section of the file.
///
/// See ISOBMFF (ISO 14496-12:2020) § 4.2
#[derive(Debug, Clone, Copy)]
struct BoxHeader {
 /// Box type.
 name: BoxType,
 /// Size of the box in bytes.
 size: u64,
 /// Offset to the start of the contained data (or header size).
 offset: u64,
 /// Uuid for extended type.
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 uuid: Option<[u8; 16]>,
}

impl BoxHeader {
 const MIN_SIZE: u64 = 8; // 4-byte size + 4-byte type
 const MIN_LARGE_SIZE: u64 = 16; // 4-byte size + 4-byte type + 16-byte size
}

/// File type box 'ftyp'.
#[derive(Debug)]
struct FileTypeBox {
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 major_brand: FourCC,
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 minor_version: u32,
 compatible_brands: TryVec<FourCC>,
}

impl FileTypeBox {
 fn contains(&self, brand: &FourCC) -> bool {
 self.compatible_brands.contains(brand) || self.major_brand == *brand
 }
}

/// Movie header box 'mvhd'.
#[derive(Debug)]
struct MovieHeaderBox {
 pub timescale: u32,
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 duration: u64,
}

#[derive(Debug, Clone, Copy)]
pub struct Matrix {
 pub a: i32, // 16.16 fix point
 pub b: i32, // 16.16 fix point
 pub u: i32, // 2.30 fix point
 pub c: i32, // 16.16 fix point
 pub d: i32, // 16.16 fix point
 pub v: i32, // 2.30 fix point
 pub x: i32, // 16.16 fix point
 pub y: i32, // 16.16 fix point
 pub w: i32, // 2.30 fix point
}

/// Track header box 'tkhd'
#[derive(Debug, Clone)]
pub struct TrackHeaderBox {
 track_id: u32,
 pub disabled: bool,
 pub duration: u64,
 pub width: u32,
 pub height: u32,
 pub matrix: Matrix,
}

/// Edit list box 'elst'
#[derive(Debug)]
struct EditListBox {
 looped: bool,
 edits: TryVec<Edit>,
}

#[derive(Debug)]
struct Edit {
 segment_duration: u64,
 media_time: i64,
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 media_rate_integer: i16,
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 media_rate_fraction: i16,
}

/// Media header box 'mdhd'
#[derive(Debug)]
struct MediaHeaderBox {
 timescale: u32,
 duration: u64,
}

// Chunk offset box 'stco' or 'co64'
#[derive(Debug)]
pub struct ChunkOffsetBox {
 pub offsets: TryVec<u64>,
}

// Sync sample box 'stss'
#[derive(Debug)]
pub struct SyncSampleBox {
 pub samples: TryVec<u32>,
}

// Sample to chunk box 'stsc'
#[derive(Debug)]
pub struct SampleToChunkBox {
 pub samples: TryVec<SampleToChunk>,
}

#[derive(Debug)]
pub struct SampleToChunk {
 pub first_chunk: u32,
 pub samples_per_chunk: u32,
 pub sample_description_index: u32,
}

// Sample size box 'stsz'
#[derive(Debug)]
pub struct SampleSizeBox {
 pub sample_size: u32,
 pub sample_sizes: TryVec<u32>,
}

// Time to sample box 'stts'
#[derive(Debug)]
pub struct TimeToSampleBox {
 pub samples: TryVec<Sample>,
}

#[repr(C)]
#[derive(Debug)]
pub struct Sample {
 pub sample_count: u32,
 pub sample_delta: u32,
}

#[derive(Debug, Clone, Copy)]
pub enum TimeOffsetVersion {
 Version0(u32),
 Version1(i32),
}

#[derive(Debug, Clone)]
pub struct TimeOffset {
 pub sample_count: u32,
 pub time_offset: TimeOffsetVersion,
}

#[derive(Debug)]
pub struct CompositionOffsetBox {
 pub samples: TryVec<TimeOffset>,
}

// Handler reference box 'hdlr'
#[derive(Debug)]
struct HandlerBox {
 handler_type: FourCC,
}

// Sample description box 'stsd'
#[derive(Debug)]
pub struct SampleDescriptionBox {
 pub descriptions: TryVec<SampleEntry>,
}

#[derive(Debug)]
pub enum SampleEntry {
 Audio(AudioSampleEntry),
 Video(VideoSampleEntry),
 Unknown,
}

#[derive(Debug)]
pub struct TrackReferenceBox {
 pub references: TryVec<TrackReferenceEntry>,
}

impl TrackReferenceBox {
 pub fn has_auxl_reference(&self, track_id: u32) -> bool {
 self.references.iter().any(|entry| match entry {
 TrackReferenceEntry::Auxiliary(aux_entry) => aux_entry.track_ids.contains(&track_id),
 })
 }
}

#[derive(Debug)]
pub enum TrackReferenceEntry {
 Auxiliary(TrackReference),
}

#[derive(Debug)]
pub struct TrackReference {
 pub track_ids: TryVec<u32>,
}

/// An Elementary Stream Descriptor
/// See MPEG-4 Systems (ISO 14496-1:2010) § 7.2.6.5
#[allow(non_camel_case_types)]
#[derive(Debug, Default)]
pub struct ES_Descriptor {
 pub audio_codec: CodecType,
 pub audio_object_type: Option<u16>,
 pub extended_audio_object_type: Option<u16>,
 pub audio_sample_rate: Option<u32>,
 pub audio_channel_count: Option<u16>,
 #[cfg(feature = "mp4v")]
 pub video_codec: CodecType,
 pub codec_esds: TryVec<u8>,
 pub decoder_specific_data: TryVec<u8>, // Data in DECODER_SPECIFIC_TAG
}

#[allow(non_camel_case_types)]
#[derive(Debug)]
pub enum AudioCodecSpecific {
 ES_Descriptor(ES_Descriptor),
 FLACSpecificBox(FLACSpecificBox),
 OpusSpecificBox(OpusSpecificBox),
 ALACSpecificBox(ALACSpecificBox),
 MP3,
 LPCM,
 #[cfg(feature = "3gpp")]
 AMRSpecificBox(TryVec<u8>),
}

#[derive(Debug)]
pub struct AudioSampleEntry {
 pub codec_type: CodecType,
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 data_reference_index: u16,
 pub channelcount: u32,
 pub samplesize: u16,
 pub samplerate: f64,
 pub codec_specific: AudioCodecSpecific,
 pub protection_info: TryVec<ProtectionSchemeInfoBox>,
}

#[derive(Debug)]
pub enum VideoCodecSpecific {
 AVCConfig(TryVec<u8>),
 VPxConfig(VPxConfigBox),
 AV1Config(AV1ConfigBox),
 ESDSConfig(TryVec<u8>),
 H263Config(TryVec<u8>),
 HEVCConfig(TryVec<u8>),
}

#[derive(Debug)]
pub struct VideoSampleEntry {
 pub codec_type: CodecType,
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 data_reference_index: u16,
 pub width: u16,
 pub height: u16,
 pub codec_specific: VideoCodecSpecific,
 pub protection_info: TryVec<ProtectionSchemeInfoBox>,
}

/// Represent a Video Partition Codec Configuration 'vpcC' box (aka vp9). The meaning of each
/// field is covered in detail in "VP Codec ISO Media File Format Binding".
#[derive(Debug)]
pub struct VPxConfigBox {
 /// An integer that specifies the VP codec profile.
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 profile: u8,
 /// An integer that specifies a VP codec level all samples conform to the following table.
 /// For a description of the various levels, please refer to the VP9 Bitstream Specification.
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 level: u8,
 /// An integer that specifies the bit depth of the luma and color components. Valid values
 /// are 8, 10, and 12.
 pub bit_depth: u8,
 /// Really an enum defined by the "Colour primaries" section of ISO 23091-2:2019 § 8.1.
 pub colour_primaries: u8,
 /// Really an enum defined by "VP Codec ISO Media File Format Binding".
 pub chroma_subsampling: u8,
 /// Really an enum defined by the "Transfer characteristics" section of ISO 23091-2:2019 § 8.2.
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 transfer_characteristics: u8,
 /// Really an enum defined by the "Matrix coefficients" section of ISO 23091-2:2019 § 8.3.
 /// Available in 'VP Codec ISO Media File Format' version 1 only.
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 matrix_coefficients: Option<u8>,
 /// Indicates the black level and range of the luma and chroma signals. 0 = legal range
 /// (e.g. 16-235 for 8 bit sample depth); 1 = full range (e.g. 0-255 for 8-bit sample depth).
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 video_full_range_flag: bool,
 /// This is not used for VP8 and VP9 . Intended for binary codec initialization data.
 pub codec_init: TryVec<u8>,
}

/// See [AV1-ISOBMFF § 2.3.3](https://aomediacodec.github.io/av1-isobmff/#av1codecconfigurationbox-syntax)
#[derive(Debug)]
pub struct AV1ConfigBox {
 pub profile: u8,
 pub level: u8,
 pub tier: u8,
 pub bit_depth: u8,
 pub monochrome: bool,
 pub chroma_subsampling_x: u8,
 pub chroma_subsampling_y: u8,
 pub chroma_sample_position: u8,
 pub initial_presentation_delay_present: bool,
 pub initial_presentation_delay_minus_one: u8,
 // The raw config contained in the av1c box. Because some decoders accept this data as a binary
 // blob, rather than as structured data, we store the blob here for convenience.
 pub raw_config: TryVec<u8>,
}

impl AV1ConfigBox {
 const CONFIG_OBUS_OFFSET: usize = 4;

 pub fn config_obus(&self) -> &[u8] {
 &self.raw_config[Self::CONFIG_OBUS_OFFSET..]
 }
}

#[derive(Debug)]
pub struct FLACMetadataBlock {
 pub block_type: u8,
 pub data: TryVec<u8>,
}

/// Represents a FLACSpecificBox 'dfLa'
#[derive(Debug)]
pub struct FLACSpecificBox {
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 version: u8,
 pub blocks: TryVec<FLACMetadataBlock>,
}

#[derive(Debug)]
struct ChannelMappingTable {
 stream_count: u8,
 coupled_count: u8,
 channel_mapping: TryVec<u8>,
}

/// Represent an OpusSpecificBox 'dOps'
#[derive(Debug)]
pub struct OpusSpecificBox {
 pub version: u8,
 output_channel_count: u8,
 pre_skip: u16,
 input_sample_rate: u32,
 output_gain: i16,
 channel_mapping_family: u8,
 channel_mapping_table: Option<ChannelMappingTable>,
}

/// Represent an ALACSpecificBox 'alac'
#[derive(Debug)]
pub struct ALACSpecificBox {
 #[allow(dead_code)] // See https://github.com/mozilla/mp4parse-rust/issues/340
 version: u8,
 pub data: TryVec<u8>,
}

#[derive(Debug)]
pub struct MovieExtendsBox {
 pub fragment_duration: Option<MediaScaledTime>,
}

pub type ByteData = TryVec<u8>;

#[derive(Debug, Default)]
pub struct ProtectionSystemSpecificHeaderBox {
 pub system_id: ByteData,
 pub kid: TryVec<ByteData>,
 pub data: ByteData,

 // The entire pssh box (include header) required by Gecko.
 pub box_content: ByteData,
}

#[derive(Debug, Default, Clone)]
pub struct SchemeTypeBox {
 pub scheme_type: FourCC,
 pub scheme_version: u32,
}

#[derive(Debug, Default)]
pub struct TrackEncryptionBox {
 pub is_encrypted: u8,
 pub iv_size: u8,
 pub kid: TryVec<u8>,
 // Members for pattern encryption schemes
 pub crypt_byte_block_count: Option<u8>,
 pub skip_byte_block_count: Option<u8>,
 pub constant_iv: Option<TryVec<u8>>,
 // End pattern encryption scheme members
}

#[derive(Debug, Default)]
pub struct ProtectionSchemeInfoBox {
 pub original_format: FourCC,
 pub scheme_type: Option<SchemeTypeBox>,
 pub tenc: Option<TrackEncryptionBox>,
}

/// Represents a userdata box 'udta'.
/// Currently, only the metadata atom 'meta'
/// is parsed.
#[derive(Debug, Default)]
pub struct UserdataBox {
 pub meta: Option<MetadataBox>,
}

/// Represents possible contents of the
/// ©gen or gnre atoms within a metadata box.
/// 'udta.meta.ilst' may only have either a
/// standard genre box 'gnre' or a custom
/// genre box '©gen', but never both at once.
#[derive(Debug, PartialEq)]
pub enum Genre {
 /// A standard ID3v1 numbered genre.
 StandardGenre(u8),
 /// Any custom genre string.
 CustomGenre(TryString),
}

/// Represents the contents of a 'stik'
/// atom that indicates content types within
/// iTunes.
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum MediaType {
 /// Movie is stored as 0 in a 'stik' atom.
 Movie, // 0
 /// Normal is stored as 1 in a 'stik' atom.
 Normal, // 1
 /// AudioBook is stored as 2 in a 'stik' atom.
 AudioBook, // 2
 /// WhackedBookmark is stored as 5 in a 'stik' atom.
 WhackedBookmark, // 5
 /// MusicVideo is stored as 6 in a 'stik' atom.
 MusicVideo, // 6
 /// ShortFilm is stored as 9 in a 'stik' atom.
 ShortFilm, // 9
 /// TVShow is stored as 10 in a 'stik' atom.
 TVShow, // 10
 /// Booklet is stored as 11 in a 'stik' atom.
 Booklet, // 11
 /// An unknown 'stik' value.
 Unknown(u8),
}

/// Represents the parental advisory rating on the track,
/// stored within the 'rtng' atom.
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum AdvisoryRating {
 /// Clean is always stored as 2 in an 'rtng' atom.
 Clean, // 2
 /// A value of 0 in an 'rtng' atom indicates 'Inoffensive'
 Inoffensive, // 0
 /// Any non 2 or 0 value in 'rtng' indicates the track is explicit.
 Explicit(u8),
}

/// Represents the contents of 'ilst' atoms within
/// a metadata box 'meta', parsed as iTunes metadata using
/// the conventional tags.
#[derive(Debug, Default)]
pub struct MetadataBox {
 /// The album name, '©alb'
 pub album: Option<TryString>,
 /// The artist name '©art' or '©ART'
 pub artist: Option<TryString>,
 /// The album artist 'aART'
 pub album_artist: Option<TryString>,
 /// Track comments '©cmt'
 pub comment: Option<TryString>,
 /// The date or year field '©day'
 ///
 /// This is stored as an arbitrary string,
 /// and may not necessarily be in a valid date
 /// format.
 pub year: Option<TryString>,
 /// The track title '©nam'
 pub title: Option<TryString>,
 /// The track genre '©gen' or 'gnre'.
 pub genre: Option<Genre>,
 /// The track number 'trkn'.
 pub track_number: Option<u8>,
 /// The disc number 'disk'
 pub disc_number: Option<u8>,
 /// The total number of tracks on the disc,
 /// stored in 'trkn'
 pub total_tracks: Option<u8>,
 /// The total number of discs in the album,
 /// stored in 'disk'
 pub total_discs: Option<u8>,
 /// The composer of the track '©wrt'
 pub composer: Option<TryString>,
 /// The encoder used to create this track '©too'
 pub encoder: Option<TryString>,
 /// The encoded-by settingo this track '©enc'
 pub encoded_by: Option<TryString>,
 /// The tempo or BPM of the track 'tmpo'
 pub beats_per_minute: Option<u8>,
 /// Copyright information of the track 'cprt'
 pub copyright: Option<TryString>,
 /// Whether or not this track is part of a compilation 'cpil'
 pub compilation: Option<bool>,
 /// The advisory rating of this track 'rtng'
 pub advisory: Option<AdvisoryRating>,
 /// The personal rating of this track, 'rate'.
 ///
 /// This is stored in the box as string data, but
 /// the format is an integer percentage from 0 - 100,
 /// where 100 is displayed as 5 stars out of 5.
 pub rating: Option<TryString>,
 /// The grouping this track belongs to '©grp'
 pub grouping: Option<TryString>,
 /// The media type of this track 'stik'
 pub media_type: Option<MediaType>, // stik
 /// Whether or not this track is a podcast 'pcst'
 pub podcast: Option<bool>,
 /// The category of ths track 'catg'
 pub category: Option<TryString>,
 /// The podcast keyword 'keyw'
 pub keyword: Option<TryString>,
 /// The podcast url 'purl'
 pub podcast_url: Option<TryString>,
 /// The podcast episode GUID 'egid'
 pub podcast_guid: Option<TryString>,
 /// The description of the track 'desc'
 pub description: Option<TryString>,
 /// The long description of the track 'ldes'.
 ///
 /// Unlike other string fields, the long description field
 /// can be longer than 256 characters.
 pub long_description: Option<TryString>,
 /// The lyrics of the track '©lyr'.
 ///
 /// Unlike other string fields, the lyrics field
 /// can be longer than 256 characters.
 pub lyrics: Option<TryString>,
 /// The name of the TV network this track aired on 'tvnn'.
 pub tv_network_name: Option<TryString>,
 /// The name of the TV Show for this track 'tvsh'.
 pub tv_show_name: Option<TryString>,
 /// The name of the TV Episode for this track 'tven'.
 pub tv_episode_name: Option<TryString>,
 /// The number of the TV Episode for this track 'tves'.
 pub tv_episode_number: Option<u8>,
 /// The season of the TV Episode of this track 'tvsn'.
 pub tv_season: Option<u8>,
 /// The date this track was purchased 'purd'.
 pub purchase_date: Option<TryString>,
 /// Whether or not this track supports gapless playback 'pgap'
 pub gapless_playback: Option<bool>,
 /// Any cover artwork attached to this track 'covr'
 ///
 /// 'covr' is unique in that it may contain multiple 'data' sub-entries,
 /// each an image file. Here, each subentry's raw binary data is exposed,
 /// which may contain image data in JPEG or PNG format.
 pub cover_art: Option<TryVec<TryVec<u8>>>,
 /// The owner of the track 'ownr'
 pub owner: Option<TryString>,
 /// Whether or not this track is HD Video 'hdvd'
 pub hd_video: Option<bool>,
 /// The name of the track to sort by 'sonm'
 pub sort_name: Option<TryString>,
 /// The name of the album to sort by 'soal'
 pub sort_album: Option<TryString>,
 /// The name of the artist to sort by 'soar'
 pub sort_artist: Option<TryString>,
 /// The name of the album artist to sort by 'soaa'
 pub sort_album_artist: Option<TryString>,
 /// The name of the composer to sort by 'soco'
 pub sort_composer: Option<TryString>,
 /// Metadata
 #[cfg(feature = "meta-xml")]
 pub xml: Option<XmlBox>,
}

/// See ISOBMFF (ISO 14496-12:2020) § 8.11.2.1
#[cfg(feature = "meta-xml")]
#[derive(Debug)]
pub enum XmlBox {
 /// XML metadata
 StringXmlBox(TryString),
 /// Binary XML metadata
 BinaryXmlBox(TryVec<u8>),
}

/// Internal data structures.
#[derive(Debug, Default)]
pub struct MediaContext {
 pub timescale: Option<MediaTimeScale>,
 /// Tracks found in the file.
 pub tracks: TryVec<Track>,
 pub mvex: Option<MovieExtendsBox>,
 pub psshs: TryVec<ProtectionSystemSpecificHeaderBox>,
 pub userdata: Option<Result<UserdataBox>>,
 #[cfg(feature = "meta-xml")]
 pub metadata: Option<Result<MetadataBox>>,
}

/// An ISOBMFF item as described by an iloc box. For the sake of avoiding copies,
/// this can either be represented by the `Location` variant, which indicates
/// where the data exists within a `DataBox` stored separately, or the `Data`
/// variant which owns the data. Unfortunately, it's not simple to represent
/// this as a [`std::borrow::Cow`], or other reference-based type, because
/// multiple instances may references different parts of the same [`DataBox`]
/// and we want to avoid the copy that splitting the storage would entail.
enum IsobmffItem {
 MdatLocation(Extent),
 IdatLocation(Extent),
 Data(TryVec<u8>),
}

impl fmt::Debug for IsobmffItem {
 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 match &self {
 IsobmffItem::MdatLocation(extent) | IsobmffItem::IdatLocation(extent) => f
 .debug_struct("IsobmffItem::Location")
 .field("0", &format_args!("{extent:?}"))
 .finish(),
 IsobmffItem::Data(data) => f
 .debug_struct("IsobmffItem::Data")
 .field("0", &format_args!("{} bytes", data.len()))
 .finish(),
 }
 }
}

#[derive(Debug)]
struct AvifItem {
 /// The `item_ID` from ISOBMFF (ISO 14496-12:2020) § 8.11.3
 ///
 /// See [`read_iloc`]
 id: ItemId,

 /// AV1 Image Item per <https://aomediacodec.github.io/av1-avif/#image-item>
 image_data: IsobmffItem,
}

impl AvifItem {
 fn with_inline_data(id: ItemId) -> Self {
 Self {
 id,
 image_data: IsobmffItem::Data(TryVec::new()),
 }
 }
}

#[derive(Default, Debug)]
pub struct AvifContext {
 /// Level of deviation from the specification before failing the parse
 strictness: ParseStrictness,
 /// Storage elements which can be located anywhere within the "file" identified by
 /// [`BoxType::ItemLocationBox`]es using [`ConstructionMethod::File`].
 /// Referred to by the [`IsobmffItem`]`::*Location` variants of the `AvifItem`s in this struct
 media_storage: TryVec<DataBox>,
 /// Similar to `media_storage`, but for a single optional chunk of storage within the
 /// MetaBox itentified by [`BoxType::ItemLocationBox`]es using [`ConstructionMethod::Idat`].
 item_data_box: Option<DataBox>,
 /// The item indicated by the `pitm` box, See ISOBMFF (ISO 14496-12:2020) § 8.11.4
 /// May be `None` in the pure image sequence case.
 primary_item: Option<AvifItem>,
 /// Associated alpha channel for the primary item, if any
 alpha_item: Option<AvifItem>,
 /// If true, divide RGB values by the alpha value.
 /// See `prem` in MIAF (ISO 23000-22:2019) § 7.3.5.2
 pub premultiplied_alpha: bool,
 /// All properties associated with `primary_item` or `alpha_item`
 item_properties: ItemPropertiesBox,
 /// Should probably only ever be [`AVIF_BRAND`] or [`AVIS_BRAND`], but other values
 /// are legal as long as one of the two is the `compatible_brand` list.
 pub major_brand: FourCC,
 /// Information on the sequence contained in the image, or None if not present
 pub sequence: Option<MediaContext>,
 /// A collection of unsupported features encountered during the parse
 pub unsupported_features: UnsupportedFeatures,
}

impl AvifContext {
 pub fn primary_item_is_present(&self) -> bool {
 self.primary_item.is_some()
 }

 pub fn primary_item_coded_data(&self) -> Option<&[u8]> {
 self.primary_item
 .as_ref()
 .map(|item| self.item_as_slice(item))
 }

 pub fn primary_item_bits_per_channel(&self) -> Option<Result<&[u8]>> {
 self.primary_item
 .as_ref()
 .map(|item| self.image_bits_per_channel(item.id))
 }

 pub fn alpha_item_is_present(&self) -> bool {
 self.alpha_item.is_some()
 }

 pub fn alpha_item_coded_data(&self) -> Option<&[u8]> {
 self.alpha_item
 .as_ref()
 .map(|item| self.item_as_slice(item))
 }

 pub fn alpha_item_bits_per_channel(&self) -> Option<Result<&[u8]>> {
 self.alpha_item
 .as_ref()
 .map(|item| self.image_bits_per_channel(item.id))
 }

 fn image_bits_per_channel(&self, item_id: ItemId) -> Result<&[u8]> {
 match self
 .item_properties
 .get(item_id, BoxType::PixelInformationBox)?
 {
 Some(ItemProperty::Channels(pixi)) => Ok(pixi.bits_per_channel.as_slice()),
 Some(other_property) => panic!("property key mismatch: {:?}", other_property),
 None => Ok(&[]),
 }
 }

 pub fn spatial_extents_ptr(&self) -> Result<*const ImageSpatialExtentsProperty> {
 if let Some(primary_item) = &self.primary_item {
 match self
 .item_properties
 .get(primary_item.id, BoxType::ImageSpatialExtentsProperty)?
 {
 Some(ItemProperty::ImageSpatialExtents(ispe)) => Ok(ispe),
 Some(other_property) => panic!("property key mismatch: {:?}", other_property),
 None => {
 fail_with_status_if(
 self.strictness != ParseStrictness::Permissive,
 Status::IspeMissing,
 )?;
 Ok(std::ptr::null())
 }
 }
 } else {
 Ok(std::ptr::null())
 }
 }

 /// Returns None if there is no primary item or it has no associated NCLX colour boxes.
 pub fn nclx_colour_information_ptr(&self) -> Option<Result<*const NclxColourInformation>> {
 if let Some(primary_item) = &self.primary_item {
 match self.item_properties.get_multiple(primary_item.id, |prop| {
 matches!(prop, ItemProperty::Colour(ColourInformation::Nclx(_)))
 }) {
 Ok(nclx_colr_boxes) => match *nclx_colr_boxes.as_slice() {
 [] => None,
 [ItemProperty::Colour(ColourInformation::Nclx(nclx)), ..] => {
 if nclx_colr_boxes.len() > 1 {
 warn!("Multiple nclx colr boxes, using first");
 }
 Some(Ok(nclx))
 }
 _ => unreachable!("Expect only ColourInformation::Nclx(_) matches"),
 },
 Err(e) => Some(Err(e)),
 }
 } else {
 None
 }
 }

 /// Returns None if there is no primary item or it has no associated ICC colour boxes.
 pub fn icc_colour_information(&self) -> Option<Result<&[u8]>> {
 if let Some(primary_item) = &self.primary_item {
 match self.item_properties.get_multiple(primary_item.id, |prop| {
 matches!(prop, ItemProperty::Colour(ColourInformation::Icc(_, _)))
 }) {
 Ok(icc_colr_boxes) => match *icc_colr_boxes.as_slice() {
 [] => None,
 [ItemProperty::Colour(ColourInformation::Icc(icc, _)), ..] => {
 if icc_colr_boxes.len() > 1 {
 warn!("Multiple ICC profiles in colr boxes, using first");
 }
 Some(Ok(icc.bytes.as_slice()))
 }
 _ => unreachable!("Expect only ColourInformation::Icc(_) matches"),
 },
 Err(e) => Some(Err(e)),
 }
 } else {
 None
 }
 }

 pub fn image_rotation(&self) -> Result<ImageRotation> {
 if let Some(primary_item) = &self.primary_item {
 match self
 .item_properties
 .get(primary_item.id, BoxType::ImageRotation)?
 {
 Some(ItemProperty::Rotation(irot)) => Ok(*irot),
 Some(other_property) => panic!("property key mismatch: {:?}", other_property),
 None => Ok(ImageRotation::D0),
 }
 } else {
 Ok(ImageRotation::D0)
 }
 }

 pub fn image_mirror_ptr(&self) -> Result<*const ImageMirror> {
 if let Some(primary_item) = &self.primary_item {
 match self
 .item_properties
 .get(primary_item.id, BoxType::ImageMirror)?
 {
 Some(ItemProperty::Mirroring(imir)) => Ok(imir),
 Some(other_property) => panic!("property key mismatch: {:?}", other_property),
 None => Ok(std::ptr::null()),
 }
 } else {
 Ok(std::ptr::null())
 }
 }

 pub fn pixel_aspect_ratio_ptr(&self) -> Result<*const PixelAspectRatio> {
 if let Some(primary_item) = &self.primary_item {
 match self
 .item_properties
 .get(primary_item.id, BoxType::PixelAspectRatioBox)?
 {
 Some(ItemProperty::PixelAspectRatio(pasp)) => Ok(pasp),
 Some(other_property) => panic!("property key mismatch: {:?}", other_property),
 None => Ok(std::ptr::null()),
 }
 } else {
 Ok(std::ptr::null())
 }
 }

 /// A helper for the various `AvifItem`s to expose a reference to the
 /// underlying data while avoiding copies.
 fn item_as_slice<'a>(&'a self, item: &'a AvifItem) -> &'a [u8] {
 match &item.image_data {
 IsobmffItem::MdatLocation(extent) => {
 for mdat in &self.media_storage {
 if let Some(slice) = mdat.get(extent) {
 return slice;
 }
 }
 unreachable!(
 "IsobmffItem::MdatLocation requires the location exists in AvifContext::media_storage"
 );
 }
 IsobmffItem::IdatLocation(extent) => {
 self.item_data_box
 .as_ref()
 .and_then(|idat| idat.get(extent))
 .unwrap_or_else(|| unreachable!("IsobmffItem::IdatLocation equires the location exists in AvifContext::item_data_box"))
 }
 IsobmffItem::Data(data) => data.as_slice(),
 }
 }
}

struct AvifMeta {
 item_references: TryVec<SingleItemTypeReferenceBox>,
 item_properties: ItemPropertiesBox,
 /// Required for AvifImageType::Primary, but optional otherwise
 /// See HEIF (ISO/IEC 23008-12:2017) § 7.1, 10.2.1
 primary_item_id: Option<ItemId>,
 item_infos: TryVec<ItemInfoEntry>,
 iloc_items: TryHashMap<ItemId, ItemLocationBoxItem>,
 item_data_box: Option<DataBox>,
}

#[derive(Debug)]
enum DataBoxMetadata {
 Idat,
 Mdat {
 /// Offset of `data` from the beginning of the "file". See ConstructionMethod::File.
 /// Note: the file may not be an actual file, read_avif supports any `&mut impl Read`
 /// source for input. However we try to match the terminology used in the spec.
 file_offset: u64,
 },
}

/// Represents either an Item Data Box (ISOBMFF (ISO 14496-12:2020) § 8.11.11)
/// Or a Media Data Box (ISOBMFF (ISO 14496-12:2020) § 8.1.1)
struct DataBox {
 metadata: DataBoxMetadata,
 data: TryVec<u8>,
}

impl fmt::Debug for DataBox {
 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 f.debug_struct("DataBox")
 .field("metadata", &self.metadata)
 .field("data", &format_args!("{} bytes", self.data.len()))
 .finish()
 }
}

fn u64_to_usize_logged(x: u64) -> Option<usize> {
 match x.try_into() {
 Ok(x) => Some(x),
 Err(e) => {
 error!("{:?} converting {:?}", e, x);
 None
 }
 }
}

impl DataBox {
 fn from_mdat(file_offset: u64, data: TryVec<u8>) -> Self {
 Self {
 metadata: DataBoxMetadata::Mdat { file_offset },
 data,
 }
 }

 fn from_idat(data: TryVec<u8>) -> Self {
 Self {
 metadata: DataBoxMetadata::Idat,
 data,
 }
 }

 fn data(&self) -> &[u8] {
 &self.data
 }

 /// Convert an absolute offset to an offset relative to the beginning of the
 /// slice [`DataBox::data`] returns. Returns None if the offset would be
 /// negative or if the offset would overflow a `usize`.
 fn start(&self, offset: u64) -> Option<usize> {
 match self.metadata {
 DataBoxMetadata::Idat => u64_to_usize_logged(offset),
 DataBoxMetadata::Mdat { file_offset } => {
 let start = offset.checked_sub(file_offset);
 if start.is_none() {
 error!("Overflow subtracting {} + {}", offset, file_offset);
 }
 u64_to_usize_logged(start?)
 }
 }
 }

 /// Returns an appropriate variant of [`IsobmffItem`] to describe the extent
 /// referencing data within this type of box.
 fn location(&self, extent: &Extent) -> IsobmffItem {
 match self.metadata {
 DataBoxMetadata::Idat => IsobmffItem::IdatLocation(extent.clone()),
 DataBoxMetadata::Mdat { .. } => IsobmffItem::MdatLocation(extent.clone()),
 }
 }

 /// Return a slice from the DataBox specified by the provided `extent`.
 /// Returns `None` if the extent isn't fully contained by the DataBox or if
 /// either the offset or length (if the extent is bounded) of the slice
 /// would overflow a `usize`.
 fn get<'a>(&'a self, extent: &'a Extent) -> Option<&'a [u8]> {
 match extent {
 Extent::WithLength { offset, len } => {
 let start = self.start(*offset)?;
 let end = start.checked_add(*len);
 if end.is_none() {
 error!("Overflow adding {} + {}", start, len);
 }
 self.data().get(start..end?)
 }
 Extent::ToEnd { offset } => {
 let start = self.start(*offset)?;
 self.data().get(start..)
 }
 }
 }
}

#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
struct PropertyIndex(u16);
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, PartialOrd)]
struct ItemId(u32);

impl ItemId {
 fn read(src: &mut impl ReadBytesExt, version: u8) -> Result<ItemId> {
 Ok(ItemId(if version == 0 {
 be_u16(src)?.into()
 } else {
 be_u32(src)?
 }))
 }
}

/// Used for 'infe' boxes within 'iinf' boxes
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.6
/// Only versions {2, 3} are supported
#[derive(Debug)]
struct ItemInfoEntry {
 item_id: ItemId,
 item_type: u32,
}

/// See ISOBMFF (ISO 14496-12:2020) § 8.11.12
#[derive(Debug)]
struct SingleItemTypeReferenceBox {
 item_type: FourCC,
 from_item_id: ItemId,
 to_item_id: ItemId,
}

/// Potential sizes (in bytes) of variable-sized fields of the 'iloc' box
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.3
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum IlocFieldSize {
 Zero,
 Four,
 Eight,
}

impl IlocFieldSize {
 fn as_bits(&self) -> u8 {
 match self {
 IlocFieldSize::Zero => 0,
 IlocFieldSize::Four => 32,
 IlocFieldSize::Eight => 64,
 }
 }
}

impl TryFrom<u8> for IlocFieldSize {
 type Error = Error;

 fn try_from(value: u8) -> Result<Self> {
 match value {
 0 => Ok(Self::Zero),
 4 => Ok(Self::Four),
 8 => Ok(Self::Eight),
 _ => Status::IlocBadFieldSize.into(),
 }
 }
}

#[derive(Debug, PartialEq, Eq)]
enum IlocVersion {
 Zero,
 One,
 Two,
}

impl TryFrom<u8> for IlocVersion {
 type Error = Error;

 fn try_from(value: u8) -> Result<Self> {
 match value {
 0 => Ok(Self::Zero),
 1 => Ok(Self::One),
 2 => Ok(Self::Two),
 _ => Err(Error::Unsupported("unsupported version in 'iloc' box")),
 }
 }
}

/// Used for 'iloc' boxes
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.3
/// `base_offset` is omitted since it is integrated into the ranges in `extents`
/// `data_reference_index` is omitted, since only 0 (i.e., this file) is supported
#[derive(Debug)]
struct ItemLocationBoxItem {
 construction_method: ConstructionMethod,
 /// Unused for ConstructionMethod::Idat
 extents: TryVec<Extent>,
}

/// See ISOBMFF (ISO 14496-12:2020) § 8.11.3
///
/// Note: per MIAF (ISO 23000-22:2019) § 7.2.1.7: 
/// > MIAF image items are constrained as follows: 
/// > — `construction_method` shall be equal to 0 for MIAF image items that are coded image items. 
/// > — `construction_method` shall be equal to 0 or 1 for MIAF image items that are derived image items.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
enum ConstructionMethod {
 File = 0,
 Idat = 1,
 Item = 2,
}

/// Describes a region where a item specified by an `ItemLocationBoxItem` is stored.
/// The offset is `u64` since that's the maximum possible size and since the relative
/// nature of `DataBox` means this can still possibly succeed even in the case
/// that the raw value exceeds std::usize::MAX on platforms where that type is smaller
/// than u64. However, `len` is stored as a `usize` since no value larger than
/// `std::usize::MAX` can be used in a successful indexing operation in rust.
/// `extent_index` is omitted since it's only used for ConstructionMethod::Item which
/// is currently not implemented.
#[derive(Clone, Debug)]
enum Extent {
 WithLength { offset: u64, len: usize },
 ToEnd { offset: u64 },
}

#[derive(Debug, PartialEq, Eq, Default)]
pub enum TrackType {
 Audio,
 Video,
 Picture,
 AuxiliaryVideo,
 Metadata,
 #[default]
 Unknown,
}

// This type is used by mp4parse_capi since it needs to be passed from FFI consumers
// The C-visible struct is renamed via mp4parse_capi/cbindgen.toml to match naming conventions
#[repr(C)]
#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
pub enum ParseStrictness {
 Permissive, // Error only on ambiguous inputs
 #[default]
 Normal, // Error on "shall" directives, log warnings for "should"
 Strict, // Error on "should" directives
}

fn fail_with_status_if(violation: bool, status: Status) -> Result<()> {
 let error = Error::from(status);
 if violation {
 Err(error)
 } else {
 warn!("{:?}", error);
 Ok(())
 }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum CodecType {
 #[default]
 Unknown,
 MP3,
 AAC,
 FLAC,
 Opus,
 H264, // 14496-10
 MP4V, // 14496-2
 AV1,
 VP9,
 VP8,
 EncryptedVideo,
 EncryptedAudio,
 LPCM, // QT
 ALAC,
 H263,
 HEVC, // 23008-2
 #[cfg(feature = "3gpp")]
 AMRNB,
 #[cfg(feature = "3gpp")]
 AMRWB,
}

/// The media's global (mvhd) timescale in units per second.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct MediaTimeScale(pub u64);

/// A time to be scaled by the media's global (mvhd) timescale.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct MediaScaledTime(pub u64);

/// The track's local (mdhd) timescale.
/// Members are timescale units per second and the track id.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct TrackTimeScale<T: Num>(pub T, pub usize);

/// A time to be scaled by the track's local (mdhd) timescale.
/// Members are time in scale units and the track id.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct TrackScaledTime<T>(pub T, pub usize);

impl<T> std::ops::Add for TrackScaledTime<T>
where
 T: num_traits::CheckedAdd,
{
 type Output = Option<Self>;

 fn add(self, other: TrackScaledTime<T>) -> Self::Output {
 self.0.checked_add(&other.0).map(|sum| Self(sum, self.1))
 }
}

#[derive(Debug, Default)]
pub struct Track {
 pub id: usize,
 pub track_type: TrackType,
 pub looped: Option<bool>,
 pub empty_duration: Option<MediaScaledTime>,
 pub edited_duration: Option<MediaScaledTime>,
 pub media_time: Option<TrackScaledTime<u64>>,
 pub timescale: Option<TrackTimeScale<u64>>,
 pub duration: Option<TrackScaledTime<u64>>,
 pub track_id: Option<u32>,
 pub tkhd: Option<TrackHeaderBox>, // TODO(kinetik): find a nicer way to export this.
 pub stsd: Option<SampleDescriptionBox>,
 pub stts: Option<TimeToSampleBox>,
 pub stsc: Option<SampleToChunkBox>,
 pub stsz: Option<SampleSizeBox>,
 pub stco: Option<ChunkOffsetBox>, // It is for stco or co64.
 pub stss: Option<SyncSampleBox>,
 pub ctts: Option<CompositionOffsetBox>,
 pub tref: Option<TrackReferenceBox>,
}

impl Track {
 fn new(id: usize) -> Track {
 Track {
 id,
 ..Default::default()
 }
 }
}

/// See ISOBMFF (ISO 14496-12:2020) § 4.2
struct BMFFBox<'a, T: 'a> {
 head: BoxHeader,
 content: Take<&'a mut T>,
}

struct BoxIter<'a, T: 'a> {
 src: &'a mut T,
}

impl<'a, T: Read> BoxIter<'a, T> {
 fn new(src: &mut T) -> BoxIter<T> {
 BoxIter { src }
 }

 fn next_box(&mut self) -> Result<Option<BMFFBox<T>>> {
 let r = read_box_header(self.src);
 match r {
 Ok(h) => Ok(Some(BMFFBox {
 head: h,
 content: self.src.take(h.size.saturating_sub(h.offset)),
 })),
 Err(Error::UnexpectedEOF) => Ok(None),
 Err(e) => Err(e),
 }
 }
}

impl<'a, T: Read> Read for BMFFBox<'a, T> {
 fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
 self.content.read(buf)
 }
}

impl<'a, T: Read> TryRead for BMFFBox<'a, T> {
 fn try_read_to_end(&mut self, buf: &mut TryVec<u8>) -> std::io::Result<usize> {
 fallible_collections::try_read_up_to(self, self.bytes_left(), buf)
 }
}

impl<'a, T: Offset> Offset for BMFFBox<'a, T> {
 fn offset(&self) -> u64 {
 self.content.get_ref().offset()
 }
}

impl<'a, T: Read> BMFFBox<'a, T> {
 fn bytes_left(&self) -> u64 {
 self.content.limit()
 }

 fn get_header(&self) -> &BoxHeader {
 &self.head
 }

 fn box_iter<'b>(&'b mut self) -> BoxIter<BMFFBox<'a, T>> {
 BoxIter::new(self)
 }
}

impl<'a, T> Drop for BMFFBox<'a, T> {
 fn drop(&mut self) {
 if self.content.limit() > 0 {
 let name: FourCC = From::from(self.head.name);
 debug!("Dropping {} bytes in '{}'", self.content.limit(), name);
 }
 }
}

/// Read and parse a box header.
///
/// Call this first to determine the type of a particular mp4 box
/// and its length. Used internally for dispatching to specific
/// parsers for the internal content, or to get the length to
/// skip unknown or uninteresting boxes.
///
/// See ISOBMFF (ISO 14496-12:2020) § 4.2
fn read_box_header<T: ReadBytesExt>(src: &mut T) -> Result<BoxHeader> {
 let size32 = match be_u32(src) {
 Ok(v) => v,
 Err(error) => return Err(error),
 };
 let name = BoxType::from(be_u32(src)?);
 let size = match size32 {
 // valid only for top-level box and indicates it's the last box in the file. usually mdat.
 0 => {
 if name == BoxType::MediaDataBox {
 0
 } else {
 return Err(Error::Unsupported("unknown sized box"));
 }
 }
 1 => be_u64(src)?,
 _ => u64::from(size32),
 };
 trace!("read_box_header: name: {:?}, size: {}", name, size);
 let mut offset = match size32 {
 1 => BoxHeader::MIN_LARGE_SIZE,
 _ => BoxHeader::MIN_SIZE,
 };
 let uuid = if name == BoxType::UuidBox {
 if size >= offset + 16 {
 let mut buffer = [0u8; 16];
 let count = src.read(&mut buffer)?;
 offset += count.to_u64();
 if count == 16 {
 Some(buffer)
 } else {
 debug!("malformed uuid (short read)");
 return Err(Error::UnexpectedEOF);
 }
 } else {
 None
 }
 } else {
 None
 };
 match size32 {
 0 => (),
 1 if offset > size => return Err(Error::from(Status::BoxBadWideSize)),
 _ if offset > size => return Err(Error::from(Status::BoxBadSize)),
 _ => (),
 }
 Ok(BoxHeader {
 name,
 size,
 offset,
 uuid,
 })
}

/// Parse the extra header fields for a full box.
fn read_fullbox_extra<T: ReadBytesExt>(src: &mut T) -> Result<(u8, u32)> {
 let version = src.read_u8()?;
 let flags_a = src.read_u8()?;
 let flags_b = src.read_u8()?;
 let flags_c = src.read_u8()?;
 Ok((
 version,
 u32::from(flags_a) << 16 | u32::from(flags_b) << 8 | u32::from(flags_c),
 ))
}

// Parse the extra fields for a full box whose flag fields must be zero.
fn read_fullbox_version_no_flags<T: ReadBytesExt>(src: &mut T) -> Result<u8> {
 let (version, flags) = read_fullbox_extra(src)?;

 if flags != 0 {
 return Err(Error::Unsupported("expected flags to be 0"));
 }

 Ok(version)
}

/// Skip over the entire contents of a box.
fn skip_box_content<T: Read>(src: &mut BMFFBox<T>) -> Result<()> {
 // Skip the contents of unknown chunks.
 let to_skip = {
 let header = src.get_header();
 debug!("{:?} (skipped)", header);
 header
 .size
 .checked_sub(header.offset)
 .ok_or(Error::Unsupported("Skipping past unknown sized box"))?
 };
 assert_eq!(to_skip, src.bytes_left());
 skip(src, to_skip)
}

/// Skip over the remain data of a box.
fn skip_box_remain<T: Read>(src: &mut BMFFBox<T>) -> Result<()> {
 let remain = {
 let header = src.get_header();
 let len = src.bytes_left();
 debug!("remain {} (skipped) in {:?}", len, header);
 len
 };
 skip(src, remain)
}

#[derive(Debug)]
enum AvifImageType {
 Primary,
 Sequence,
 Both,
}

impl AvifImageType {
 fn has_primary(&self) -> bool {
 match self {
 Self::Primary | Self::Both => true,
 Self::Sequence => false,
 }
 }

 fn has_sequence(&self) -> bool {
 match self {
 Self::Primary => false,
 Self::Sequence | Self::Both => true,
 }
 }
}

/// Read the contents of an AVIF file
pub fn read_avif<T: Read>(f: &mut T, strictness: ParseStrictness) -> Result<AvifContext> {
 debug!("read_avif(strictness: {:?})", strictness);

 let mut f = OffsetReader::new(f);
 let mut iter = BoxIter::new(&mut f);
 let expected_image_type;
 let mut unsupported_features = UnsupportedFeatures::new();

 // 'ftyp' box must occur first; see ISOBMFF (ISO 14496-12:2020) § 4.3.1
 let major_brand = if let Some(mut b) = iter.next_box()? {
 if b.head.name == BoxType::FileTypeBox {
 let ftyp = read_ftyp(&mut b)?;

 let has_avif_brand = ftyp.contains(&AVIF_BRAND);
 let has_avis_brand = ftyp.contains(&AVIS_BRAND);
 let has_mif1_brand = ftyp.contains(&MIF1_BRAND);
 let has_msf1_brand = ftyp.contains(&MSF1_BRAND);

 let primary_image_expected = has_mif1_brand || has_avif_brand;
 let image_sequence_expected = has_msf1_brand || has_avis_brand;

 expected_image_type = if primary_image_expected && image_sequence_expected {
 AvifImageType::Both
 } else if primary_image_expected {
 AvifImageType::Primary
 } else if image_sequence_expected {
 AvifImageType::Sequence
 } else {
 return Status::NoImage.into();
 };
 debug!("expected_image_type: {:?}", expected_image_type);

 if primary_image_expected && !has_mif1_brand {
 fail_with_status_if(
 strictness == ParseStrictness::Strict,
 Status::MissingMif1Brand,
 )?;
 }

 if !has_avif_brand && !has_avis_brand {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::MissingAvifOrAvisBrand,
 )?;
 }

 ftyp.major_brand
 } else {
 return Status::FtypNotFirst.into();
 }
 } else {
 return Status::FtypNotFirst.into();
 };

 let mut meta = None;
 let mut image_sequence = None;
 let mut media_storage = TryVec::new();

 loop {
 let mut b = match iter.next_box() {
 Ok(Some(b)) => b,
 Ok(_) => break,
 Err(Error::UnexpectedEOF) => {
 if strictness == ParseStrictness::Strict {
 return Err(Error::UnexpectedEOF);
 }
 break;
 }
 Err(error) => return Err(error),
 };

 trace!("read_avif parsing {:?} box", b.head.name);
 match b.head.name {
 BoxType::MetadataBox => {
 if meta.is_some() {
 return Status::MetaBadQuantity.into();
 }
 meta = Some(read_avif_meta(
 &mut b,
 strictness,
 &mut unsupported_features,
 )?);
 }
 BoxType::MovieBox if expected_image_type.has_sequence() => {
 if image_sequence.is_some() {
 return Status::MoovBadQuantity.into();
 }
 image_sequence = Some(read_moov(&mut b, None)?);
 }
 BoxType::MediaDataBox => {
 let file_offset = b.offset();
 let data = if b.head.size == 0 {
 // Unknown sized `mdat`, read in chunks until EOF.
 const BUF_SIZE: usize = 64 * 1024;
 let mut data = TryVec::with_capacity(BUF_SIZE)?;
 loop {
 let got = fallible_collections::try_read_up_to(
 b.content.get_mut(),
 BUF_SIZE as u64,
 &mut data,
 )?;
 if got == 0 {
 // Mark `content` as consumed.
 b.content.set_limit(0);
 break;
 }
 }
 data
 } else {
 b.read_into_try_vec()?
 };
 media_storage.push(DataBox::from_mdat(file_offset, data))?;
 }
 _ => {
 let result = skip_box_content(&mut b);
 // Allow garbage at EOF if we aren't in strict mode.
 if b.bytes_left() > 0 && strictness != ParseStrictness::Strict {
 break;
 }
 result?;
 }
 }

 check_parser_state!(b.content);
 }

 let AvifMeta {
 item_references,
 item_properties,
 primary_item_id,
 item_infos,
 iloc_items,
 item_data_box,
 } = meta.ok_or_else(|| Error::from(Status::MetaBadQuantity))?;

 let (alpha_item_id, premultiplied_alpha) = if let Some(primary_item_id) = primary_item_id {
 let mut alpha_item_ids = item_references
 .iter()
 // Auxiliary image for the primary image
 .filter(|iref| {
 iref.to_item_id == primary_item_id
 && iref.from_item_id != primary_item_id
 && iref.item_type == b"auxl"
 })
 .map(|iref| iref.from_item_id)
 // which has the alpha property
 .filter(|&item_id| item_properties.is_alpha(item_id));
 let alpha_item_id = alpha_item_ids.next();
 if alpha_item_ids.next().is_some() {
 return Status::MultipleAlpha.into();
 }

 let premultiplied_alpha = alpha_item_id.map_or(false, |alpha_item_id| {
 item_references.iter().any(|iref| {
 iref.from_item_id == primary_item_id
 && iref.to_item_id == alpha_item_id
 && iref.item_type == b"prem"
 })
 });

 (alpha_item_id, premultiplied_alpha)
 } else {
 (None, false)
 };

 debug!("primary_item_id: {:?}", primary_item_id);
 debug!("alpha_item_id: {:?}", alpha_item_id);
 let mut primary_item = None;
 let mut alpha_item = None;

 // store data or record location of relevant items
 for (item_id, loc) in iloc_items {
 let item = if Some(item_id) == primary_item_id {
 &mut primary_item
 } else if Some(item_id) == alpha_item_id {
 &mut alpha_item
 } else {
 continue;
 };

 assert!(item.is_none());

 // If our item is spread over multiple extents, we'll need to copy it
 // into a contiguous buffer. Otherwise, we can just store the extent
 // and return a pointer into the mdat/idat later to avoid the copy.
 if loc.extents.len() > 1 {
 *item = Some(AvifItem::with_inline_data(item_id))
 }

 trace!(
 "{:?} construction_method: {:?}",
 item_id,
 loc.construction_method
 );

 // Generalize the process of connecting items to their data; returns
 // true if the extent is successfully added to the AvifItem
 let mut find_and_add_to_item = |extent: &Extent, dat: &DataBox| -> Result<bool> {
 if let Some(extent_slice) = dat.get(extent) {
 match item {
 None => {
 trace!("Using IsobmffItem::Location");
 *item = Some(AvifItem {
 id: item_id,
 image_data: dat.location(extent),
 });
 }
 Some(AvifItem {
 image_data: IsobmffItem::Data(bytes),
 ..
 }) => {
 trace!("Using IsobmffItem::Data");
 // We could potentially optimize memory usage by trying to avoid reading
 // or storing dat boxes which aren't used by our API, but for now it seems
 // like unnecessary complexity
 bytes.extend_from_slice(extent_slice)?;
 }
 _ => unreachable!(),
 }
 return Ok(true);
 }
 Ok(false)
 };

 match loc.construction_method {
 ConstructionMethod::File => {
 for extent in loc.extents {
 let mut found = false;
 // try to find an mdat which contains the extent
 for mdat in media_storage.iter() {
 if find_and_add_to_item(&extent, mdat)? {
 found = true;
 break;
 }
 }

 if !found {
 return Status::IlocNotFound.into();
 }
 }
 }
 ConstructionMethod::Idat => {
 if let Some(idat) = &item_data_box {
 for extent in loc.extents {
 let found = find_and_add_to_item(&extent, idat)?;
 if !found {
 return Status::IlocNotFound.into();
 }
 }
 } else {
 return Status::IdatMissing.into();
 }
 }
 ConstructionMethod::Item => {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::ConstructionMethod,
 )?;
 }
 }

 assert!(item.is_some());
 }

 if (primary_item_id.is_some() && primary_item.is_none())
 || (alpha_item_id.is_some() && alpha_item.is_none())
 {
 fail_with_status_if(strictness == ParseStrictness::Strict, Status::PitmNotFound)?;
 }

 assert!(primary_item.is_none() || primary_item_id.is_some());
 assert!(alpha_item.is_none() || alpha_item_id.is_some());

 if expected_image_type.has_primary() && primary_item_id.is_none() {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::PitmMissing,
 )?;
 }

 // Lacking a brand that requires them, it's fine for moov boxes to exist in
 // BMFF files; they're simply ignored
 if expected_image_type.has_sequence() && image_sequence.is_none() {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::MoovMissing,
 )?;
 }

 // Returns true iff `id` is `Some` and there is no corresponding property for it
 let missing_property_for = |id: Option<ItemId>, property: BoxType| -> bool {
 id.map_or(false, |id| {
 item_properties
 .get(id, property)
 .map_or(true, |opt| opt.is_none())
 })
 };

 // Generalize the property checks so we can apply them to primary and alpha items
 let mut check_image_item = |item: &mut Option<AvifItem>| -> Result<()> {
 let item_id = item.as_ref().map(|item| item.id);
 let item_type = item_id.and_then(|item_id| {
 item_infos
 .iter()
 .find(|item_info| item_id == item_info.item_id)
 .map(|item_info| item_info.item_type)
 });

 match item_type.map(u32::to_be_bytes).as_ref() {
 Some(b"av01") => {
 if missing_property_for(item_id, BoxType::AV1CodecConfigurationBox) {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::Av1cMissing,
 )?;
 }

 if missing_property_for(item_id, BoxType::PixelInformationBox) {
 // The requirement to include pixi is in the process of being changed
 // to allowing its omission to imply a default value. In anticipation
 // of that, only give an error in strict mode
 // See https://github.com/MPEGGroup/MIAF/issues/9
 fail_with_status_if(
 if cfg!(feature = "missing-pixi-permitted") {
 strictness == ParseStrictness::Strict
 } else {
 strictness != ParseStrictness::Permissive
 },
 Status::PixiMissing,
 )?;
 }

 if missing_property_for(item_id, BoxType::ImageSpatialExtentsProperty) {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::IspeMissing,
 )?;
 }
 }
 Some(b"grid") => {
 // TODO: https://github.com/mozilla/mp4parse-rust/issues/198
 unsupported_features.insert(Feature::Grid);
 *item = None;
 }
 Some(_other_type) => return Status::ImageItemType.into(),
 None => {
 if item.is_some() {
 return Status::ItemTypeMissing.into();
 }
 }
 }

 if let Some(AvifItem { id, .. }) = item {
 if item_properties.forbidden_items.contains(id) {
 error!("Not processing item id {:?} since it is associated with essential, but unsupported properties", id);
 *item = None;
 }
 }

 Ok(())
 };

 check_image_item(&mut primary_item)?;
 check_image_item(&mut alpha_item)?;

 Ok(AvifContext {
 strictness,
 media_storage,
 item_data_box,
 primary_item,
 alpha_item,
 premultiplied_alpha,
 item_properties,
 major_brand,
 sequence: image_sequence,
 unsupported_features,
 })
}

/// Parse a metadata box in the context of an AVIF
/// Currently requires the primary item to be an av01 item type and generates
/// an error otherwise.
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.1
fn read_avif_meta<T: Read + Offset>(
 src: &mut BMFFBox<T>,
 strictness: ParseStrictness,
 unsupported_features: &mut UnsupportedFeatures,
) -> Result<AvifMeta> {
 let version = read_fullbox_version_no_flags(src)?;

 if version != 0 {
 return Err(Error::Unsupported("unsupported meta version"));
 }

 let mut read_handler_box = false;
 let mut primary_item_id = None;
 let mut item_infos = None;
 let mut iloc_items = None;
 let mut item_references = None;
 let mut item_properties = None;
 let mut item_data_box = None;

 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 trace!("read_avif_meta parsing {:?} box", b.head.name);

 if !read_handler_box && b.head.name != BoxType::HandlerBox {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::HdlrNotFirst,
 )?;
 }

 match b.head.name {
 BoxType::HandlerBox => {
 if read_handler_box {
 return Status::HdrlBadQuantity.into();
 }
 let HandlerBox { handler_type } = read_hdlr(&mut b, strictness)?;
 if handler_type != b"pict" {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::HdlrTypeNotPict,
 )?;
 }
 read_handler_box = true;
 }
 BoxType::ItemInfoBox => {
 if item_infos.is_some() {
 return Status::IinfBadQuantity.into();
 }
 item_infos = Some(read_iinf(&mut b, strictness, unsupported_features)?);
 }
 BoxType::ItemLocationBox => {
 if iloc_items.is_some() {
 return Status::IlocBadQuantity.into();
 }
 iloc_items = Some(read_iloc(&mut b)?);
 }
 BoxType::PrimaryItemBox => {
 if primary_item_id.is_some() {
 return Status::PitmBadQuantity.into();
 }
 primary_item_id = Some(read_pitm(&mut b)?);
 }
 BoxType::ItemReferenceBox => {
 if item_references.is_some() {
 return Status::IrefBadQuantity.into();
 }
 item_references = Some(read_iref(&mut b)?);
 }
 BoxType::ItemPropertiesBox => {
 if item_properties.is_some() {
 return Status::IprpBadQuantity.into();
 }
 item_properties = Some(read_iprp(
 &mut b,
 MIF1_BRAND,
 strictness,
 unsupported_features,
 )?);
 }
 BoxType::ItemDataBox => {
 if item_data_box.is_some() {
 return Status::IdatBadQuantity.into();
 }
 let data = b.read_into_try_vec()?;
 item_data_box = Some(DataBox::from_idat(data));
 }
 _ => skip_box_content(&mut b)?,
 }

 check_parser_state!(b.content);
 }

 Ok(AvifMeta {
 item_properties: item_properties.unwrap_or_default(),
 item_references: item_references.unwrap_or_default(),
 primary_item_id,
 item_infos: item_infos.unwrap_or_default(),
 iloc_items: iloc_items.unwrap_or_default(),
 item_data_box,
 })
}

/// Parse a Primary Item Box
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.4
fn read_pitm<T: Read>(src: &mut BMFFBox<T>) -> Result<ItemId> {
 let version = read_fullbox_version_no_flags(src)?;

 let item_id = ItemId(match version {
 0 => be_u16(src)?.into(),
 1 => be_u32(src)?,
 _ => return Err(Error::Unsupported("unsupported pitm version")),
 });

 Ok(item_id)
}

/// Parse an Item Information Box
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.6
fn read_iinf<T: Read>(
 src: &mut BMFFBox<T>,
 strictness: ParseStrictness,
 unsupported_features: &mut UnsupportedFeatures,
) -> Result<TryVec<ItemInfoEntry>> {
 let version = read_fullbox_version_no_flags(src)?;

 match version {
 0 | 1 => (),
 _ => return Err(Error::Unsupported("unsupported iinf version")),
 }

 let entry_count = if version == 0 {
 be_u16(src)?.to_usize()
 } else {
 be_u32(src)?.to_usize()
 };
 let mut item_infos = TryVec::with_capacity(entry_count)?;

 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 if b.head.name != BoxType::ItemInfoEntry {
 return Status::IinfBadChild.into();
 }

 if let Some(infe) = read_infe(&mut b, strictness, unsupported_features)? {
 item_infos.push(infe)?;
 }

 check_parser_state!(b.content);
 }

 Ok(item_infos)
}

/// A simple wrapper to interpret a u32 as a 4-byte string in big-endian
/// order without requiring any allocation.
struct U32BE(u32);

impl std::fmt::Display for U32BE {
 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 match std::str::from_utf8(&self.0.to_be_bytes()) {
 Ok(s) => f.write_str(s),
 Err(_) => write!(f, "{:x?}", self.0),
 }
 }
}

/// Parse an Item Info Entry
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.6.2
fn read_infe<T: Read>(
 src: &mut BMFFBox<T>,
 strictness: ParseStrictness,
 unsupported_features: &mut UnsupportedFeatures,
) -> Result<Option<ItemInfoEntry>> {
 let (version, flags) = read_fullbox_extra(src)?;

 // According to the standard, it seems the flags field shall be 0, but at
 // least one sample AVIF image has a nonzero value.
 // See https://github.com/AOMediaCodec/av1-avif/issues/146
 if flags != 0 {
 fail_with_status_if(
 strictness == ParseStrictness::Strict,
 Status::InfeFlagsNonzero,
 )?;
 }

 // mif1 brand (see HEIF (ISO 23008-12:2017) § 10.2.1) only requires v2 and 3
 let item_id = ItemId(match version {
 2 => be_u16(src)?.into(),
 3 => be_u32(src)?,
 _ => return Err(Error::Unsupported("unsupported version in 'infe' box")),
 });

 let item_protection_index = be_u16(src)?;

 let item_type = be_u32(src)?;
 debug!("infe {:?} item_type: {}", item_id, U32BE(item_type));

 // There are some additional fields here, but they're not of interest to us
 skip_box_remain(src)?;

 if item_protection_index != 0 {
 unsupported_features.insert(Feature::Ipro);
 Ok(None)
 } else {
 Ok(Some(ItemInfoEntry { item_id, item_type }))
 }
}

/// Parse an Item Reference Box
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.12
fn read_iref<T: Read>(src: &mut BMFFBox<T>) -> Result<TryVec<SingleItemTypeReferenceBox>> {
 let mut item_references = TryVec::new();
 let version = read_fullbox_version_no_flags(src)?;
 if version > 1 {
 return Err(Error::Unsupported("iref version"));
 }

 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 trace!("read_iref parsing {:?} referenceType", b.head.name);
 let from_item_id = ItemId::read(&mut b, version)?;
 let reference_count = be_u16(&mut b)?;
 item_references.reserve(reference_count.to_usize())?;
 for _ in 0..reference_count {
 let to_item_id = ItemId::read(&mut b, version)?;
 if from_item_id == to_item_id {
 return Status::IrefRecursion.into();
 }
 item_references.push(SingleItemTypeReferenceBox {
 item_type: b.head.name.into(),
 from_item_id,
 to_item_id,
 })?;
 }
 check_parser_state!(b.content);
 }

 trace!("read_iref -> {:#?}", item_references);

 Ok(item_references)
}

/// Parse an Item Properties Box
///
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.14)
///
/// Note: HEIF (ISO 23008-12:2017) § 9.3.1 also defines the `iprp` box and
/// related types, but lacks additional requirements specified in 14496-12:2020.
///
/// Note: Currently HEIF (ISO 23008-12:2017) § 6.5.5.1 specifies "At most one"
/// `colr` box per item, but this is being amended in [DIS 23008-12](https://www.iso.org/standard/83650.html).
/// The new text is likely to be "At most one for a given value of `colour_type`",
/// so this implementation adheres to that language for forward compatibility.
fn read_iprp<T: Read>(
 src: &mut BMFFBox<T>,
 brand: FourCC,
 strictness: ParseStrictness,
 unsupported_features: &mut UnsupportedFeatures,
) -> Result<ItemPropertiesBox> {
 let mut iter = src.box_iter();

 let properties = match iter.next_box()? {
 Some(mut b) if b.head.name == BoxType::ItemPropertyContainerBox => {
 read_ipco(&mut b, strictness)
 }
 Some(_) => Status::IprpBadChild.into(),
 None => Err(Error::UnexpectedEOF),
 }?;

 let mut ipma_version_and_flag_values_seen = TryVec::with_capacity(1)?;
 let mut association_entries = TryVec::<ItemPropertyAssociationEntry>::new();
 let mut forbidden_items = TryVec::new();

 while let Some(mut b) = iter.next_box()? {
 if b.head.name != BoxType::ItemPropertyAssociationBox {
 return Status::IprpBadChild.into();
 }

 let (version, flags) = read_fullbox_extra(&mut b)?;
 if ipma_version_and_flag_values_seen.contains(&(version, flags)) {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::IpmaBadQuantity,
 )?;
 }
 if flags != 0 && properties.len() <= 127 {
 fail_with_status_if(
 strictness == ParseStrictness::Strict,
 Status::IpmaFlagsNonzero,
 )?;
 }
 ipma_version_and_flag_values_seen.push((version, flags))?;
 for association_entry in read_ipma(&mut b, strictness, version, flags)? {
 if forbidden_items.contains(&association_entry.item_id) {
 warn!(
 "Skipping {:?} since the item referenced shall not be processed",
 association_entry
 );
 }

 if let Some(previous_entry) = association_entries
 .iter()
 .find(|e| association_entry.item_id == e.item_id)
 {
 error!(
 "Duplicate ipma entries for item_id\n1: {:?}\n2: {:?}",
 previous_entry, association_entry
 );
 // It's technically possible to make sense of this situation by merging ipma
 // boxes, but this is a "shall" requirement, so we'd only do it in
 // ParseStrictness::Permissive mode, and this hasn't shown up in the wild
 return Status::IpmaDuplicateItemId.into();
 }

 const TRANSFORM_ORDER: &[BoxType] = &[
 BoxType::ImageSpatialExtentsProperty,
 BoxType::CleanApertureBox,
 BoxType::ImageRotation,
 BoxType::ImageMirror,
 ];
 let mut prev_transform_index = None;
 // Realistically, there should only ever be 1 nclx and 1 icc
 let mut colour_type_indexes: TryHashMap<FourCC, PropertyIndex> =
 TryHashMap::with_capacity(2)?;

 for a in &association_entry.associations {
 if a.property_index == PropertyIndex(0) {
 if a.essential {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::IpmaIndexZeroNoEssential,
 )?;
 }
 continue;
 }

 if let Some(property) = properties.get(&a.property_index) {
 assert!(brand == MIF1_BRAND);

 let feature = Feature::try_from(property);
 let property_supported = match feature {
 Ok(feature) => {
 if feature.supported() {
 true
 } else {
 unsupported_features.insert(feature);
 false
 }
 }
 Err(_) => false,
 };

 if !property_supported {
 if a.essential && strictness != ParseStrictness::Permissive {
 error!("Unsupported essential property {:?}", property);
 forbidden_items.push(association_entry.item_id)?;
 } else {
 debug!(
 "Ignoring unknown {} property {:?}",
 if a.essential {
 "essential"
 } else {
 "non-essential"
 },
 property
 );
 }
 }

 // Check additional requirements on specific properties
 match property {
 ItemProperty::AV1Config(_)
 | ItemProperty::CleanAperture
 | ItemProperty::Mirroring(_)
 | ItemProperty::Rotation(_) => {
 if !a.essential {
 warn!("{:?} is missing required 'essential' bit", property);
 // This is a "shall", but it is likely to change, so only
 // fail if using strict parsing.
 // See https://github.com/mozilla/mp4parse-rust/issues/284
 fail_with_status_if(
 strictness == ParseStrictness::Strict,
 Status::TxformNoEssential,
 )?;
 }
 }

 // NOTE: this is contrary to the published specification; see doc comment
 // at the beginning of this function for more details
 ItemProperty::Colour(colr) => {
 let colour_type = colr.colour_type();
 if let Some(prev_colr_index) = colour_type_indexes.get(&colour_type) {
 warn!(
 "Multiple '{}' type colr associations with {:?}: {:?} and {:?}",
 colour_type,
 association_entry.item_id,
 a.property_index,
 prev_colr_index
 );
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::ColrBadQuantity,
 )?;
 } else {
 colour_type_indexes.insert(colour_type, a.property_index)?;
 }
 }

 // The following properties are unsupported, but we still enforce that
 // they've been correctly marked as essential or not.
 ItemProperty::LayeredImageIndexing => {
 assert!(feature.is_ok() && unsupported_features.contains(feature?));
 if a.essential {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::A1lxEssential,
 )?;
 }
 }

 ItemProperty::LayerSelection => {
 assert!(feature.is_ok() && unsupported_features.contains(feature?));
 if a.essential {
 assert!(
 forbidden_items.contains(&association_entry.item_id)
 || strictness == ParseStrictness::Permissive
 );
 } else {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::LselNoEssential,
 )?;
 }
 }

 ItemProperty::OperatingPointSelector => {
 assert!(feature.is_ok() && unsupported_features.contains(feature?));
 if a.essential {
 assert!(
 forbidden_items.contains(&association_entry.item_id)
 || strictness == ParseStrictness::Permissive
 );
 } else {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::A1opNoEssential,
 )?;
 }
 }

 other_property => {
 trace!("No additional checks for {:?}", other_property);
 }
 }

 if let Some(transform_index) = TRANSFORM_ORDER
 .iter()
 .position(|t| *t == BoxType::from(property))
 {
 if let Some(prev) = prev_transform_index {
 if prev >= transform_index {
 error!(
 "Invalid property order: {:?} after {:?}",
 TRANSFORM_ORDER[transform_index], TRANSFORM_ORDER[prev]
 );
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 if TRANSFORM_ORDER[transform_index]
 == BoxType::ImageSpatialExtentsProperty
 {
 Status::TxformBeforeIspe
 } else {
 Status::TxformOrder
 },
 )?;
 }
 }
 prev_transform_index = Some(transform_index);
 }
 } else {
 error!(
 "Missing property at {:?} for {:?}",
 a.property_index, association_entry.item_id
 );
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::IpmaBadIndex,
 )?;
 }
 }
 association_entries.push(association_entry)?
 }

 check_parser_state!(b.content);
 }

 let iprp = ItemPropertiesBox {
 properties,
 association_entries,
 forbidden_items,
 };
 trace!("read_iprp -> {:#?}", iprp);
 Ok(iprp)
}

/// See ISOBMFF (ISO 14496-12:2020) § 8.11.14.1
/// Variants with no associated data are recognized but not necessarily supported.
/// See [`Feature`] to determine support.
#[derive(Debug)]
pub enum ItemProperty {
 AuxiliaryType(AuxiliaryTypeProperty),
 AV1Config(AV1ConfigBox),
 Channels(PixelInformation),
 CleanAperture,
 Colour(ColourInformation),
 ImageSpatialExtents(ImageSpatialExtentsProperty),
 LayeredImageIndexing,
 LayerSelection,
 Mirroring(ImageMirror),
 OperatingPointSelector,
 PixelAspectRatio(PixelAspectRatio),
 Rotation(ImageRotation),
 /// Necessary to validate property indices in read_iprp
 Unsupported(BoxType),
}

impl From<&ItemProperty> for BoxType {
 fn from(item_property: &ItemProperty) -> Self {
 match item_property {
 ItemProperty::AuxiliaryType(_) => BoxType::AuxiliaryTypeProperty,
 ItemProperty::AV1Config(_) => BoxType::AV1CodecConfigurationBox,
 ItemProperty::CleanAperture => BoxType::CleanApertureBox,
 ItemProperty::Colour(_) => BoxType::ColourInformationBox,
 ItemProperty::LayeredImageIndexing => BoxType::AV1LayeredImageIndexingProperty,
 ItemProperty::LayerSelection => BoxType::LayerSelectorProperty,
 ItemProperty::Mirroring(_) => BoxType::ImageMirror,
 ItemProperty::OperatingPointSelector => BoxType::OperatingPointSelectorProperty,
 ItemProperty::PixelAspectRatio(_) => BoxType::PixelAspectRatioBox,
 ItemProperty::Rotation(_) => BoxType::ImageRotation,
 ItemProperty::ImageSpatialExtents(_) => BoxType::ImageSpatialExtentsProperty,
 ItemProperty::Channels(_) => BoxType::PixelInformationBox,
 ItemProperty::Unsupported(box_type) => *box_type,
 }
 }
}

#[derive(Debug)]
struct ItemPropertyAssociationEntry {
 item_id: ItemId,
 associations: TryVec<Association>,
}

/// For storing ItemPropertyAssociation data
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.14.1
#[derive(Debug)]
struct Association {
 essential: bool,
 property_index: PropertyIndex,
}

/// See ISOBMFF (ISO 14496-12:2020) § 8.11.14.1
///
/// The properties themselves are stored in `properties`, but the items they're
/// associated with are stored in `association_entries`. It's necessary to
/// maintain this indirection because multiple items can reference the same
/// property. For example, both the primary item and alpha item can share the
/// same [`ImageSpatialExtentsProperty`].
#[derive(Debug, Default)]
pub struct ItemPropertiesBox {
 /// `ItemPropertyContainerBox property_container` in the spec
 properties: TryHashMap<PropertyIndex, ItemProperty>,
 /// `ItemPropertyAssociationBox association[]` in the spec
 association_entries: TryVec<ItemPropertyAssociationEntry>,
 /// Items that shall not be processed due to unsupported properties that
 /// have been marked essential.
 /// See HEIF (ISO/IEC 23008-12:2017) § 9.3.1
 forbidden_items: TryVec<ItemId>,
}

impl ItemPropertiesBox {
 /// For displayable images `av1C`, `pixi` and `ispe` are mandatory, `colr`
 /// is typically included too, so we might as well use an even power of 2.
 const MIN_PROPERTIES: usize = 4;

 fn is_alpha(&self, item_id: ItemId) -> bool {
 match self.get(item_id, BoxType::AuxiliaryTypeProperty) {
 Ok(Some(ItemProperty::AuxiliaryType(urn))) => {
 urn.aux_type.as_slice() == "urn:mpeg:mpegB:cicp:systems:auxiliary:alpha".as_bytes()
 }
 Ok(Some(other_property)) => panic!("property key mismatch: {:?}", other_property),
 Ok(None) => false,
 Err(e) => {
 error!(
 "is_alpha: Error checking AuxiliaryTypeProperty ({}), returning false",
 e
 );
 false
 }
 }
 }

 fn get(&self, item_id: ItemId, property_type: BoxType) -> Result<Option<&ItemProperty>> {
 match self
 .get_multiple(item_id, |prop| BoxType::from(prop) == property_type)?
 .as_slice()
 {
 &[] => Ok(None),
 &[single_value] => Ok(Some(single_value)),
 multiple_values => {
 error!(
 "Multiple values for {:?}: {:?}",
 property_type, multiple_values
 );
 // TODO: add test
 Status::IprpConflict.into()
 }
 }
 }

 fn get_multiple(
 &self,
 item_id: ItemId,
 filter: impl Fn(&ItemProperty) -> bool,
 ) -> Result<TryVec<&ItemProperty>> {
 let mut values = TryVec::new();
 for entry in &self.association_entries {
 for a in &entry.associations {
 if entry.item_id == item_id {
 match self.properties.get(&a.property_index) {
 Some(ItemProperty::Unsupported(_)) => {}
 Some(property) if filter(property) => values.push(property)?,
 _ => {}
 }
 }
 }
 }

 Ok(values)
 }
}

/// An upper bound which can be used to check overflow at compile time
trait UpperBounded {
 const MAX: u64;
}

/// Implement type $name as a newtype wrapper around an unsigned int which
/// implements the UpperBounded trait.
macro_rules! impl_bounded {
 ( $name:ident, $inner:ty ) => {
 #[derive(Clone, Copy)]
 pub struct $name($inner);

 impl $name {
 pub const fn new(n: $inner) -> Self {
 Self(n)
 }

 #[allow(dead_code)]
 pub fn get(self) -> $inner {
 self.0
 }
 }

 impl UpperBounded for $name {
 const MAX: u64 = <$inner>::MAX as u64;
 }
 };
}

/// Implement type $name as a type representing the product of two unsigned ints
/// which implements the UpperBounded trait.
macro_rules! impl_bounded_product {
 ( $name:ident, $multiplier:ty, $multiplicand:ty, $inner:ty) => {
 #[derive(Clone, Copy)]
 pub struct $name($inner);

 impl $name {
 pub fn new(value: $inner) -> Self {
 assert!(value <= Self::MAX);
 Self(value)
 }

 pub fn get(self) -> $inner {
 self.0
 }
 }

 impl UpperBounded for $name {
 const MAX: u64 = <$multiplier>::MAX * <$multiplicand>::MAX;
 }
 };
}

mod bounded_uints {
 use crate::UpperBounded;

 impl_bounded!(U8, u8);
 impl_bounded!(U16, u16);
 impl_bounded!(U32, u32);
 impl_bounded!(U64, u64);

 impl_bounded_product!(U32MulU8, U32, U8, u64);
 impl_bounded_product!(U32MulU16, U32, U16, u64);

 impl UpperBounded for std::num::NonZeroU8 {
 const MAX: u64 = u8::MAX as u64;
 }
}

use crate::bounded_uints::*;

/// Implement the multiplication operator for $lhs * $rhs giving $output, which
/// is internally represented as $inner. The operation is statically checked
/// to ensure the product won't overflow $inner, nor exceed <$output>::MAX.
macro_rules! impl_mul {
 ( ($lhs:ty , $rhs:ty) => ($output:ty, $inner:ty) ) => {
 impl std::ops::Mul<$rhs> for $lhs {
 type Output = $output;

 fn mul(self, rhs: $rhs) -> Self::Output {
 static_assertions::const_assert!(
 <$output as UpperBounded>::MAX <= <$inner>::MAX as u64
 );
 static_assertions::const_assert!(
 <$lhs as UpperBounded>::MAX * <$rhs as UpperBounded>::MAX
 <= <$output as UpperBounded>::MAX
 );

 let lhs: $inner = self.get().into();
 let rhs: $inner = rhs.get().into();
 Self::Output::new(lhs.checked_mul(rhs).expect("infallible"))
 }
 }
 };
}

impl_mul!((U8, std::num::NonZeroU8) => (U16, u16));
impl_mul!((U32, std::num::NonZeroU8) => (U32MulU8, u64));
impl_mul!((U32, U16) => (U32MulU16, u64));

impl std::ops::Add<U32MulU16> for U32MulU8 {
 type Output = U64;

 fn add(self, rhs: U32MulU16) -> Self::Output {
 static_assertions::const_assert!(U32MulU8::MAX + U32MulU16::MAX < U64::MAX);
 let lhs: u64 = self.get();
 let rhs: u64 = rhs.get();
 Self::Output::new(lhs.checked_add(rhs).expect("infallible"))
 }
}

const MAX_IPMA_ASSOCIATION_COUNT: U8 = U8::new(u8::MAX);

/// After reading only the `entry_count` field of an ipma box, we can check its
/// basic validity and calculate (assuming validity) the number of associations
/// which will be contained (allowing preallocation of the storage).
/// All the arithmetic is compile-time verified to not overflow via supporting
/// types implementing the UpperBounded trait. Types are declared explicitly to
/// show there isn't any accidental inference to primitive types.
///
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.14.1
fn calculate_ipma_total_associations(
 version: u8,
 bytes_left: u64,
 entry_count: U32,
 num_association_bytes: std::num::NonZeroU8,
) -> Result<usize> {
 let min_entry_bytes =
 std::num::NonZeroU8::new(1 /* association_count */ + if version == 0 { 2 } else { 4 })
 .unwrap();

 let total_non_association_bytes: U32MulU8 = entry_count * min_entry_bytes;
 let total_association_bytes: u64 =
 if let Some(difference) = bytes_left.checked_sub(total_non_association_bytes.get()) {
 // All the storage for the `essential` and `property_index` parts (assuming a valid ipma box size)
 difference
 } else {
 return Status::IpmaTooSmall.into();
 };

 let max_association_bytes_per_entry: U16 = MAX_IPMA_ASSOCIATION_COUNT * num_association_bytes;
 let max_total_association_bytes: U32MulU16 = entry_count * max_association_bytes_per_entry;
 let max_bytes_left: U64 = total_non_association_bytes + max_total_association_bytes;

 if bytes_left > max_bytes_left.get() {
 return Status::IpmaTooBig.into();
 }

 let total_associations: u64 = total_association_bytes / u64::from(num_association_bytes.get());

 Ok(total_associations.try_into()?)
}

/// Parse an ItemPropertyAssociation box
///
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.14.1
fn read_ipma<T: Read>(
 src: &mut BMFFBox<T>,
 strictness: ParseStrictness,
 version: u8,
 flags: u32,
) -> Result<TryVec<ItemPropertyAssociationEntry>> {
 let entry_count = be_u32(src)?;
 let num_association_bytes =
 std::num::NonZeroU8::new(if flags & 1 == 1 { 2 } else { 1 }).unwrap();

 let total_associations = calculate_ipma_total_associations(
 version,
 src.bytes_left(),
 U32::new(entry_count),
 num_association_bytes,
 )?;
 // Assuming most items will have at least `MIN_PROPERTIES` and knowing the
 // total number of item -> property associations (`total_associations`),
 // we can provide a good estimate for how many elements we'll need in this
 // vector, even though we don't know precisely how many items there will be
 // properties for.
 let mut entries = TryVec::<ItemPropertyAssociationEntry>::with_capacity(
 total_associations / ItemPropertiesBox::MIN_PROPERTIES,
 )?;

 for _ in 0..entry_count {
 let item_id = ItemId::read(src, version)?;

 if let Some(previous_association) = entries.last() {
 #[allow(clippy::comparison_chain)]
 if previous_association.item_id > item_id {
 return Status::IpmaBadItemOrder.into();
 } else if previous_association.item_id == item_id {
 return Status::IpmaDuplicateItemId.into();
 }
 }

 let association_count = src.read_u8()?;
 let mut associations = TryVec::with_capacity(association_count.to_usize())?;
 for _ in 0..association_count {
 let association = src
 .take(num_association_bytes.get().into())
 .read_into_try_vec()?;
 let mut association = BitReader::new(association.as_slice());
 let essential = association.read_bool()?;
 let property_index =
 PropertyIndex(association.read_u16(association.remaining().try_into()?)?);
 associations.push(Association {
 essential,
 property_index,
 })?;
 }

 entries.push(ItemPropertyAssociationEntry {
 item_id,
 associations,
 })?;
 }

 check_parser_state!(src.content);

 if version != 0 {
 if let Some(ItemPropertyAssociationEntry {
 item_id: max_item_id,
 ..
 }) = entries.last()
 {
 if *max_item_id <= ItemId(u16::MAX.into()) {
 fail_with_status_if(
 strictness == ParseStrictness::Strict,
 Status::IpmaBadVersion,
 )?;
 }
 }
 }

 trace!("read_ipma -> {:#?}", entries);

 Ok(entries)
}

/// Parse an ItemPropertyContainerBox
///
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.14.1
fn read_ipco<T: Read>(
 src: &mut BMFFBox<T>,
 strictness: ParseStrictness,
) -> Result<TryHashMap<PropertyIndex, ItemProperty>> {
 let mut properties = TryHashMap::with_capacity(ItemPropertiesBox::MIN_PROPERTIES)?;

 let mut index = PropertyIndex(1); // ipma uses 1-based indexing
 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 let property = match b.head.name {
 BoxType::AuxiliaryTypeProperty => ItemProperty::AuxiliaryType(read_auxc(&'color:red'>mut b)?),
 BoxType::AV1CodecConfigurationBox => ItemProperty::AV1Config(read_av1c(&mut b)?),
 BoxType::ColourInformationBox => ItemProperty::Colour(read_colr(&mut b, strictness)?),
 BoxType::ImageMirror => ItemProperty::Mirroring(read_imir(&mut b)?),
 BoxType::ImageRotation => ItemProperty::Rotation(read_irot(&mut b)?),
 BoxType::ImageSpatialExtentsProperty => {
 ItemProperty::ImageSpatialExtents(read_ispe(&mut b)?)
 }
 BoxType::PixelAspectRatioBox => ItemProperty::PixelAspectRatio(read_pasp(&='color:red'>mut b)?),
 BoxType::PixelInformationBox => ItemProperty::Channels(read_pixi(&mut b)?),

 other_box_type => {
 // Even if we didn't do anything with other property types, we still store
 // a record at the index to identify invalid indices in ipma boxes
 skip_box_remain(&mut b)?;
 let item_property = match other_box_type {
 BoxType::AV1LayeredImageIndexingProperty => ItemProperty::LayeredImageIndexing,
 BoxType::CleanApertureBox => ItemProperty::CleanAperture,
 BoxType::LayerSelectorProperty => ItemProperty::LayerSelection,
 BoxType::OperatingPointSelectorProperty => ItemProperty::OperatingPointSelector,
 _ => {
 warn!("No ItemProperty variant for {:?}", other_box_type);
 ItemProperty::Unsupported(other_box_type)
 }
 };
 debug!("Storing empty record {:?}", item_property);
 item_property
 }
 };
 properties.insert(index, property)?;

 index = PropertyIndex(
 index
 .0
 .checked_add(1) // must include ignored properties to have correct indexes
 .ok_or_else(|| Error::from(Status::IpcoIndexOverflow))?,
 );

 check_parser_state!(b.content);
 }

 Ok(properties)
}

#[repr(C)]
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct ImageSpatialExtentsProperty {
 image_width: u32,
 image_height: u32,
}

/// Parse image spatial extents property
///
/// See HEIF (ISO 23008-12:2017) § 6.5.3.1
fn read_ispe<T: Read>(src: &mut BMFFBox<T>) -> Result<ImageSpatialExtentsProperty> {
 if read_fullbox_version_no_flags(src)? != 0 {
 return Err(Error::Unsupported("ispe version"));
 }

 let image_width = be_u32(src)?;
 let image_height = be_u32(src)?;

 Ok(ImageSpatialExtentsProperty {
 image_width,
 image_height,
 })
}

#[repr(C)]
#[derive(Debug)]
pub struct PixelAspectRatio {
 h_spacing: u32,
 v_spacing: u32,
}

/// Parse pixel aspect ratio property
///
/// See HEIF (ISO 23008-12:2017) § 6.5.4.1
/// See ISOBMFF (ISO 14496-12:2020) § 12.1.4.2
fn read_pasp<T: Read>(src: &mut BMFFBox<T>) -> Result<PixelAspectRatio> {
 let h_spacing = be_u32(src)?;
 let v_spacing = be_u32(src)?;

 Ok(PixelAspectRatio {
 h_spacing,
 v_spacing,
 })
}

#[derive(Debug)]
pub struct PixelInformation {
 bits_per_channel: TryVec<u8>,
}

/// Parse pixel information
/// See HEIF (ISO 23008-12:2017) § 6.5.6
fn read_pixi<T: Read>(src: &mut BMFFBox<T>) -> Result<PixelInformation> {
 let version = read_fullbox_version_no_flags(src)?;
 if version != 0 {
 return Err(Error::Unsupported("pixi version"));
 }

 let num_channels = src.read_u8()?;
 let mut bits_per_channel = TryVec::with_capacity(num_channels.to_usize())?;
 let num_channels_read = src.try_read_to_end(&mut bits_per_channel)?;

 if u8::try_from(num_channels_read)? != num_channels {
 return Status::PixiBadChannelCount.into();
 }

 check_parser_state!(src.content);
 Ok(PixelInformation { bits_per_channel })
}

/// Despite [Rec. ITU-T H.273] (12/2016) defining the CICP fields as having a
/// range of 0-255, and only a small fraction of those values being used,
/// ISOBMFF (ISO 14496-12:2020) § 12.1.5 defines them as 16-bit values in the
/// `colr` box. Since we have no use for the additional range, and it would
/// complicate matters later, we fallibly convert before storing the input.
///
/// [Rec. ITU-T H.273]: https://www.itu.int/rec/T-REC-H.273-201612-I/en
#[repr(C)]
#[derive(Debug)]
pub struct NclxColourInformation {
 colour_primaries: u8,
 transfer_characteristics: u8,
 matrix_coefficients: u8,
 full_range_flag: bool,
}

/// The raw bytes of the ICC profile
#[repr(C)]
pub struct IccColourInformation {
 bytes: TryVec<u8>,
}

impl fmt::Debug for IccColourInformation {
 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 f.debug_struct("IccColourInformation")
 .field("data", &format_args!("{} bytes", self.bytes.len()))
 .finish()
 }
}

#[repr(C)]
#[derive(Debug)]
pub enum ColourInformation {
 Nclx(NclxColourInformation),
 Icc(IccColourInformation, FourCC),
}

impl ColourInformation {
 fn colour_type(&self) -> FourCC {
 match self {
 Self::Nclx(_) => FourCC::from(*b"nclx"),
 Self::Icc(_, colour_type) => colour_type.clone(),
 }
 }
}

/// Parse colour information
/// See ISOBMFF (ISO 14496-12:2020) § 12.1.5
fn read_colr<T: Read>(
 src: &mut BMFFBox<T>,
 strictness: ParseStrictness,
) -> Result<ColourInformation> {
 let colour_type = be_u32(src)?.to_be_bytes();

 match &colour_type {
 b"nclx" => {
 const NUM_RESERVED_BITS: u8 = 7;
 let colour_primaries = be_u16(src)?.try_into()?;
 let transfer_characteristics = be_u16(src)?.try_into()?;
 let matrix_coefficients = be_u16(src)?.try_into()?;
 let bytes = src.read_into_try_vec()?;
 let mut bit_reader = BitReader::new(&bytes);
 let full_range_flag = bit_reader.read_bool()?;
 if bit_reader.remaining() != NUM_RESERVED_BITS.into() {
 error!(
 "read_colr expected {} reserved bits, found {}",
 NUM_RESERVED_BITS,
 bit_reader.remaining()
 );
 return Status::ColrBadSize.into();
 }
 if bit_reader.read_u8(NUM_RESERVED_BITS)? != 0 {
 fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::ColrReservedNonzero,
 )?;
 }

 Ok(ColourInformation::Nclx(NclxColourInformation {
 colour_primaries,
 transfer_characteristics,
 matrix_coefficients,
 full_range_flag,
 }))
 }
 b"rICC" | b"prof" => Ok(ColourInformation::Icc(
 IccColourInformation {
 bytes: src.read_into_try_vec()?,
 },
 FourCC::from(colour_type),
 )),
 _ => {
 error!("read_colr colour_type: {:?}", colour_type);
 Status::ColrBadType.into()
 }
 }
}

#[repr(C)]
#[derive(Clone, Copy, Debug)]
/// Rotation in the positive (that is, anticlockwise) direction
/// Visualized in terms of starting with (⥠) UPWARDS HARPOON WITH BARB LEFT FROM BAR
/// similar to a DIGIT ONE (1)
pub enum ImageRotation {
 /// ⥠ UPWARDS HARPOON WITH BARB LEFT FROM BAR
 D0,
 /// ⥞ LEFTWARDS HARPOON WITH BARB DOWN FROM BAR
 D90,
 /// ⥝ DOWNWARDS HARPOON WITH BARB RIGHT FROM BAR
 D180,
 /// ⥛ RIGHTWARDS HARPOON WITH BARB UP FROM BAR
 D270,
}

/// Parse image rotation box
/// See HEIF (ISO 23008-12:2017) § 6.5.10
fn read_irot<T: Read>(src: &mut BMFFBox<T>) -> Result<ImageRotation> {
 let irot = src.read_into_try_vec()?;
 let mut irot = BitReader::new(&irot);
 let _reserved = irot.read_u8(6)?;
 let image_rotation = match irot.read_u8(2)? {
 0 => ImageRotation::D0,
 1 => ImageRotation::D90,
 2 => ImageRotation::D180,
 3 => ImageRotation::D270,
 _ => unreachable!(),
 };

 check_parser_state!(src.content);

 Ok(image_rotation)
}

/// The axis about which the image is mirrored (opposite of flip)
/// Visualized in terms of starting with (⥠) UPWARDS HARPOON WITH BARB LEFT FROM BAR
/// similar to a DIGIT ONE (1)
#[repr(C)]
#[derive(Debug)]
pub enum ImageMirror {
 /// top and bottom parts exchanged
 /// ⥡ DOWNWARDS HARPOON WITH BARB LEFT FROM BAR
 TopBottom,
 /// left and right parts exchanged
 /// ⥜ UPWARDS HARPOON WITH BARB RIGHT FROM BAR
 LeftRight,
}

/// Parse image mirroring box
/// See HEIF (ISO 23008-12:2017) § 6.5.12 
/// Note: [ISO/IEC 23008-12:2017/DAmd 2](https://www.iso.org/standard/81688.html)
/// reverses the interpretation of the 'imir' box in § 6.5.12.3:
/// > `axis` specifies a vertical (`axis` = 0) or horizontal (`axis` = 1) axis
/// > for the mirroring operation.
///
/// is replaced with:
/// > `mode` specifies how the mirroring is performed: 0 indicates that the top
/// > and bottom parts of the image are exchanged; 1 specifies that the left and
/// > right parts are exchanged.
/// >
/// > NOTE: In Exif, orientation tag can be used to signal mirroring operations.
/// > Exif orientation tag 4 corresponds to `mode` = 0 of `ImageMirror`, and
/// > Exif orientation tag 2 corresponds to `mode` = 1 accordingly.
///
/// This implementation conforms to the text in Draft Amendment 2, which is the
/// opposite of the published standard as of 4 June 2021.
fn read_imir<T: Read>(src: &mut BMFFBox<T>) -> Result<ImageMirror> {
 let imir = src.read_into_try_vec()?;
 let mut imir = BitReader::new(&imir);
 let _reserved = imir.read_u8(7)?;
 let image_mirror = match imir.read_u8(1)? {
 0 => ImageMirror::TopBottom,
 1 => ImageMirror::LeftRight,
 _ => unreachable!(),
 };

 check_parser_state!(src.content);

 Ok(image_mirror)
}

/// See HEIF (ISO 23008-12:2017) § 6.5.8
#[derive(Debug, PartialEq)]
pub struct AuxiliaryTypeProperty {
 aux_type: TryString,
 aux_subtype: TryString,
}

/// Parse image properties for auxiliary images
/// See HEIF (ISO 23008-12:2017) § 6.5.8
fn read_auxc<T: Read>(src: &mut BMFFBox<T>) -> Result<AuxiliaryTypeProperty> {
 let version = read_fullbox_version_no_flags(src)?;
 if version != 0 {
 return Err(Error::Unsupported("auxC version"));
 }

 let mut aux = TryString::new();
 src.try_read_to_end(&mut aux)?;

 let (aux_type, aux_subtype): (TryString, TryVec<u8>);
 if let Some(nul_byte_pos) = aux.iter().position(|&b| b == b'\0') {
 let (a, b) = aux.as_slice().split_at(nul_byte_pos);
 aux_type = a.try_into()?;
 aux_subtype = (b[1..]).try_into()?;
 } else {
 aux_type = aux;
 aux_subtype = TryVec::new();
 }

 Ok(AuxiliaryTypeProperty {
 aux_type,
 aux_subtype,
 })
}

/// Parse an item location box inside a meta box
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.3
fn read_iloc<T: Read>(src: &mut BMFFBox<T>) -> Result<TryHashMap<ItemId, ItemLocationBoxItem>> {
 let version: IlocVersion = read_fullbox_version_no_flags(src)?.try_into()?;

 let iloc = src.read_into_try_vec()?;
 let mut iloc = BitReader::new(&iloc);

 let offset_size: IlocFieldSize = iloc.read_u8(4)?.try_into()?;
 let length_size: IlocFieldSize = iloc.read_u8(4)?.try_into()?;
 let base_offset_size: IlocFieldSize = iloc.read_u8(4)?.try_into()?;

 let index_size: Option<IlocFieldSize> = match version {
 IlocVersion::One | IlocVersion::Two => Some(iloc.read_u8(4)?.try_into()?),
 IlocVersion::Zero => {
 let _reserved = iloc.read_u8(4)?;
 None
 }
 };

 let item_count = match version {
 IlocVersion::Zero | IlocVersion::One => iloc.read_u32(16)?,
 IlocVersion::Two => iloc.read_u32(32)?,
 };

 let mut items = TryHashMap::with_capacity(item_count.to_usize())?;

 for _ in 0..item_count {
 let item_id = ItemId(match version {
 IlocVersion::Zero | IlocVersion::One => iloc.read_u32(16)?,
 IlocVersion::Two => iloc.read_u32(32)?,
 });

 // The spec isn't entirely clear how an `iloc` should be interpreted for version 0,
 // which has no `construction_method` field. It does say:
 // "For maximum compatibility, version 0 of this box should be used in preference to
 // version 1 with `construction_method==0`, or version 2 when possible."
 // We take this to imply version 0 can be interpreted as using file offsets.
 let construction_method = match version {
 IlocVersion::Zero => ConstructionMethod::File,
 IlocVersion::One | IlocVersion::Two => {
 let _reserved = iloc.read_u16(12)?;
 match iloc.read_u16(4)? {
 0 => ConstructionMethod::File,
 1 => ConstructionMethod::Idat,
 2 => ConstructionMethod::Item,
 _ => return Status::IlocBadConstructionMethod.into(),
 }
 }
 };

 let data_reference_index = iloc.read_u16(16)?;
 if data_reference_index != 0 {
 return Err(Error::Unsupported(
 "external file references (iloc.data_reference_index != 0) are not supported",
 ));
 }
 let base_offset = iloc.read_u64(base_offset_size.as_bits())?;
 let extent_count = iloc.read_u16(16)?;

 if extent_count < 1 {
 return Status::IlocBadExtentCount.into();
 }

 // "If only one extent is used (extent_count = 1) then either or both of the
 // offset and length may be implied"
 if extent_count != 1
 && (offset_size == IlocFieldSize::Zero || length_size == IlocFieldSize::Zero)
 {
 return Status::IlocBadExtent.into();
 }

 let mut extents = TryVec::with_capacity(extent_count.to_usize())?;

 for _ in 0..extent_count {
 // Parsed but currently ignored, see `Extent`
 let _extent_index = match &index_size {
 None | Some(IlocFieldSize::Zero) => None,
 Some(index_size) => {
 debug_assert!(version == IlocVersion::One || version == IlocVersion::Two);
 Some(iloc.read_u64(index_size.as_bits())?)
 }
 };

 // Per ISOBMFF (ISO 14496-12:2020) § 8.11.3.1:
 // "If the offset is not identified (the field has a length of zero), then the
 // beginning of the source (offset 0) is implied"
 // This behavior will follow from BitReader::read_u64(0) -> 0.
 let extent_offset = iloc.read_u64(offset_size.as_bits())?;
 let extent_length = iloc.read_u64(length_size.as_bits())?.try_into()?;

 // "If the length is not specified, or specified as zero, then the entire length of
 // the source is implied" (ibid)
 let offset = base_offset
 .checked_add(extent_offset)
 .ok_or_else(|| Error::from(Status::IlocOffsetOverflow))?;
 let extent = if extent_length == 0 {
 Extent::ToEnd { offset }
 } else {
 Extent::WithLength {
 offset,
 len: extent_length,
 }
 };

 extents.push(extent)?;
 }

 let loc = ItemLocationBoxItem {
 construction_method,
 extents,
 };

 if items.insert(item_id, loc)?.is_some() {
 return Status::IlocDuplicateItemId.into();
 }
 }

 if iloc.remaining() == 0 {
 Ok(items)
 } else {
 Status::IlocBadSize.into()
 }
}

/// Read the contents of a box, including sub boxes.
pub fn read_mp4<T: Read>(f: &mut T) -> Result<MediaContext> {
 let mut context = None;
 let mut found_ftyp = false;
 // TODO(kinetik): Top-level parsing should handle zero-sized boxes
 // rather than throwing an error.
 let mut iter = BoxIter::new(f);
 while let Some(mut b) = iter.next_box()? {
 // box ordering: ftyp before any variable length box (inc. moov),
 // but may not be first box in file if file signatures etc. present
 // fragmented mp4 order: ftyp, moov, pairs of moof/mdat (1-multiple), mfra

 // "special": uuid, wide (= 8 bytes)
 // isom: moov, mdat, free, skip, udta, ftyp, moof, mfra
 // iso2: pdin, meta
 // iso3: meco
 // iso5: styp, sidx, ssix, prft
 // unknown, maybe: id32

 // qt: pnot

 // possibly allow anything where all printable and/or all lowercase printable
 // "four printable characters from the ISO 8859-1 character set"
 match b.head.name {
 BoxType::FileTypeBox => {
 let ftyp = read_ftyp(&mut b)?;
 found_ftyp = true;
 debug!("{:?}", ftyp);
 }
 BoxType::MovieBox => {
 context = Some(read_moov(&mut b, context)?);
 }
 #[cfg(feature = "meta-xml")]
 BoxType::MetadataBox => {
 if let Some(ctx) = &mut context {
 ctx.metadata = Some(read_meta(&mut b));
 }
 }
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 if context.is_some() {
 debug!(
 "found moov {}, could stop pure 'moov' parser now",
 if found_ftyp {
 "and ftyp"
 } else {
 "but no ftyp"
 }
 );
 }
 }

 // XXX(kinetik): This isn't perfect, as a "moov" with no contents is
 // treated as okay but we haven't found anything useful. Needs more
 // thought for clearer behaviour here.
 context.ok_or(Error::MoovMissing)
}

/// Parse a Movie Header Box
/// See ISOBMFF (ISO 14496-12:2020) § 8.2.2
fn parse_mvhd<T: Read>(f: &mut BMFFBox<T>) -> Result<Option<MediaTimeScale>> {
 let mvhd = read_mvhd(f)?;
 debug!("{:?}", mvhd);
 if mvhd.timescale == 0 {
 return Status::MvhdBadTimescale.into();
 }
 let timescale = Some(MediaTimeScale(u64::from(mvhd.timescale)));
 Ok(timescale)
}

/// Parse a Movie Box
/// See ISOBMFF (ISO 14496-12:2020) § 8.2.1
/// Note that despite the spec indicating "exactly one" moov box should exist at
/// the file container level, we support reading and merging multiple moov boxes
/// such as with tests/test_case_1185230.mp4.
fn read_moov<T: Read>(f: &mut BMFFBox<T>, context: Option<MediaContext>) -> Result<MediaContext> {
 let MediaContext {
 mut timescale,
 mut tracks,
 mut mvex,
 mut psshs,
 mut userdata,
 #[cfg(feature = "meta-xml")]
 metadata,
 } = context.unwrap_or_default();

 let mut iter = f.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::MovieHeaderBox => {
 timescale = parse_mvhd(&mut b)?;
 }
 BoxType::TrackBox => {
 let mut track = Track::new(tracks.len());
 read_trak(&mut b, &mut track)?;
 tracks.push(track)?;
 }
 BoxType::MovieExtendsBox => {
 mvex = Some(read_mvex(&mut b)?);
 debug!("{:?}", mvex);
 }
 BoxType::ProtectionSystemSpecificHeaderBox => {
 let pssh = read_pssh(&mut b)?;
 debug!("{:?}", pssh);
 psshs.push(pssh)?;
 }
 BoxType::UserdataBox => {
 userdata = Some(read_udta(&mut b));
 debug!("{:?}", userdata);
 if let Some(Err(_)) = userdata {
 // There was an error parsing userdata. Such failures are not fatal to overall
 // parsing, just skip the rest of the box.
 skip_box_remain(&mut b)?;
 }
 }
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }

 Ok(MediaContext {
 timescale,
 tracks,
 mvex,
 psshs,
 userdata,
 #[cfg(feature = "meta-xml")]
 metadata,
 })
}

fn read_pssh<T: Read>(src: &mut BMFFBox<T>) -> Result<ProtectionSystemSpecificHeaderBox> {
 let len = src.bytes_left();
 let mut box_content = read_buf(src, len)?;
 let (system_id, kid, data) = {
 let pssh = &mut Cursor::new(&box_content);

 let (version, _) = read_fullbox_extra(pssh)?;

 let system_id = read_buf(pssh, 16)?;

 let mut kid = TryVec::<ByteData>::new();
 if version > 0 {
 const KID_ELEMENT_SIZE: usize = 16;
 let count = be_u32(pssh)?.to_usize();
 kid.reserve(
 count
 .checked_mul(KID_ELEMENT_SIZE)
 .ok_or_else(|| Error::from(Status::PsshSizeOverflow))?,
 )?;
 for _ in 0..count {
 let item = read_buf(pssh, KID_ELEMENT_SIZE.to_u64())?;
 kid.push(item)?;
 }
 }

 let data_size = be_u32(pssh)?;
 let data = read_buf(pssh, data_size.into())?;

 (system_id, kid, data)
 };

 let mut pssh_box = TryVec::new();
 write_be_u32(&mut pssh_box, src.head.size.try_into()?)?;
 pssh_box.extend_from_slice(b"pssh")?;
 pssh_box.append(&mut box_content)?;

 Ok(ProtectionSystemSpecificHeaderBox {
 system_id,
 kid,
 data,
 box_content: pssh_box,
 })
}

/// Parse a Movie Extends Box
/// See ISOBMFF (ISO 14496-12:2020) § 8.8.1
fn read_mvex<T: Read>(src: &mut BMFFBox<T>) -> Result<MovieExtendsBox> {
 let mut iter = src.box_iter();
 let mut fragment_duration = None;
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::MovieExtendsHeaderBox => {
 let duration = read_mehd(&mut b)?;
 fragment_duration = Some(duration);
 }
 _ => skip_box_content(&mut b)?,
 }
 }
 Ok(MovieExtendsBox { fragment_duration })
}

fn read_mehd<T: Read>(src: &mut BMFFBox<T>) -> Result<MediaScaledTime> {
 let (version, _) = read_fullbox_extra(src)?;
 let fragment_duration = match version {
 1 => be_u64(src)?,
 0 => u64::from(be_u32(src)?),
 _ => return Status::MehdBadVersion.into(),
 };
 Ok(MediaScaledTime(fragment_duration))
}

/// Parse a Track Box
/// See ISOBMFF (ISO 14496-12:2020) § 8.3.1.
fn read_trak<T: Read>(f: &mut BMFFBox<T>, track: &mut Track) -> Result<()> {
 let mut iter = f.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::TrackHeaderBox => {
 let tkhd = read_tkhd(&mut b)?;
 track.track_id = Some(tkhd.track_id);
 track.tkhd = Some(tkhd.clone());
 debug!("{:?}", tkhd);
 }
 BoxType::EditBox => read_edts(&mut b, track)?,
 BoxType::MediaBox => read_mdia(&mut b, track)?,
 BoxType::TrackReferenceBox => track.tref = Some(read_tref(&mut b)?),
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(())
}

fn read_edts<T: Read>(f: &mut BMFFBox<T>, track: &mut Track) -> Result<()> {
 let mut iter = f.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::EditListBox => {
 let elst = read_elst(&mut b)?;
 track.looped = Some(elst.looped);
 if elst.edits.is_empty() {
 debug!("empty edit list");
 continue;
 }
 let mut empty_duration = 0;
 let mut idx = 0;
 if elst.edits[idx].media_time == -1 {
 if elst.edits.len() < 2 {
 debug!("expected additional edit, ignoring edit list");
 continue;
 }
 empty_duration = elst.edits[idx].segment_duration;
 idx += 1;
 }
 track.empty_duration = Some(MediaScaledTime(empty_duration));
 let media_time = elst.edits[idx].media_time;
 if media_time < 0 {
 debug!("unexpected negative media time in edit");
 }
 track.edited_duration = Some(MediaScaledTime(elst.edits[idx].segment_duration));
 track.media_time = Some(TrackScaledTime::<u64>(
 std::cmp::max(0, media_time) as u64,
 track.id,
 ));
 if elst.edits.len() > 2 {
 debug!("ignoring edit list with {} entries", elst.edits.len());
 }
 debug!("{:?}", elst);
 }
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(())
}

#[allow(clippy::type_complexity)] // Allow the complex return, maybe rework in future
fn parse_mdhd<T: Read>(
 f: &mut BMFFBox<T>,
 track: &Track,
) -> Result<(
 MediaHeaderBox,
 Option<TrackScaledTime<u64>>,
 Option<TrackTimeScale<u64>>,
)> {
 let mdhd = read_mdhd(f)?;
 let duration = match mdhd.duration {
 std::u64::MAX => None,
 duration => Some(TrackScaledTime::<u64>(duration, track.id)),
 };
 if mdhd.timescale == 0 {
 return Status::MdhdBadTimescale.into();
 }
 let timescale = Some(TrackTimeScale::<u64>(u64::from(mdhd.timescale), track.id));
 Ok((mdhd, duration, timescale))
}

fn read_mdia<T: Read>(f: &mut BMFFBox<T>, track: &mut Track) -> Result<()> {
 let mut iter = f.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::MediaHeaderBox => {
 let (mdhd, duration, timescale) = parse_mdhd(&mut b, track)?;
 track.duration = duration;
 track.timescale = timescale;
 debug!("{:?}", mdhd);
 }
 BoxType::HandlerBox => {
 let hdlr = read_hdlr(&mut b, ParseStrictness::Permissive)?;

 match hdlr.handler_type.value.as_ref() {
 b"vide" => track.track_type = TrackType::Video,
 b"pict" => track.track_type = TrackType::Picture,
 b"auxv" => track.track_type = TrackType::AuxiliaryVideo,
 b"soun" => track.track_type = TrackType::Audio,
 b"meta" => track.track_type = TrackType::Metadata,
 _ => (),
 }
 debug!("{:?}", hdlr);
 }
 BoxType::MediaInformationBox => read_minf(&mut b, track)?,
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(())
}

fn read_tref<T: Read>(f: &mut BMFFBox<T>) -> Result<TrackReferenceBox> {
 // Will likely only see trefs with one auxl
 let mut references = TryVec::with_capacity(1)?;
 let mut iter = f.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::AuxiliaryBox => {
 references.push(TrackReferenceEntry::Auxiliary(read_tref_auxl(&mut b)?))?
 }
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(TrackReferenceBox { references })
}

fn read_tref_auxl<T: Read>(f: &mut BMFFBox<T>) -> Result<TrackReference> {
 let num_track_ids = (f.bytes_left() / std::mem::size_of::<u32>().to_u64()).try_into()?;
 let mut track_ids = TryVec::with_capacity(num_track_ids)?;
 for _ in 0..num_track_ids {
 track_ids.push(be_u32(f)?)?;
 }

 Ok(TrackReference { track_ids })
}

fn read_minf<T: Read>(f: &mut BMFFBox<T>, track: &mut Track) -> Result<()> {
 let mut iter = f.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::SampleTableBox => read_stbl(&mut b, track)?,
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(())
}

fn read_stbl<T: Read>(f: &mut BMFFBox<T>, track: &mut Track) -> Result<()> {
 let mut iter = f.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::SampleDescriptionBox => {
 let stsd = read_stsd(&mut b, track)?;
 debug!("{:?}", stsd);
 track.stsd = Some(stsd);
 }
 BoxType::TimeToSampleBox => {
 let stts = read_stts(&mut b)?;
 debug!("{:?}", stts);
 track.stts = Some(stts);
 }
 BoxType::SampleToChunkBox => {
 let stsc = read_stsc(&mut b)?;
 debug!("{:?}", stsc);
 track.stsc = Some(stsc);
 }
 BoxType::SampleSizeBox => {
 let stsz = read_stsz(&mut b)?;
 debug!("{:?}", stsz);
 track.stsz = Some(stsz);
 }
 BoxType::ChunkOffsetBox => {
 let stco = read_stco(&mut b)?;
 debug!("{:?}", stco);
 track.stco = Some(stco);
 }
 BoxType::ChunkLargeOffsetBox => {
 let co64 = read_co64(&mut b)?;
 debug!("{:?}", co64);
 track.stco = Some(co64);
 }
 BoxType::SyncSampleBox => {
 let stss = read_stss(&mut b)?;
 debug!("{:?}", stss);
 track.stss = Some(stss);
 }
 BoxType::CompositionOffsetBox => {
 let ctts = read_ctts(&mut b)?;
 debug!("{:?}", ctts);
 track.ctts = Some(ctts);
 }
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(())
}

/// Parse an ftyp box.
/// See ISOBMFF (ISO 14496-12:2020) § 4.3
fn read_ftyp<T: Read>(src: &mut BMFFBox<T>) -> Result<FileTypeBox> {
 let major = be_u32(src)?;
 let minor = be_u32(src)?;
 let bytes_left = src.bytes_left();
 if bytes_left % 4 != 0 {
 return Status::FtypBadSize.into();
 }
 // Is a brand_count of zero valid?
 let brand_count = bytes_left / 4;
 let mut brands = TryVec::with_capacity(brand_count.try_into()?)?;
 for _ in 0..brand_count {
 brands.push(be_u32(src)?.into())?;
 }
 Ok(FileTypeBox {
 major_brand: From::from(major),
 minor_version: minor,
 compatible_brands: brands,
 })
}

/// Parse an mvhd box.
fn read_mvhd<T: Read>(src: &mut BMFFBox<T>) -> Result<MovieHeaderBox> {
 let (version, _) = read_fullbox_extra(src)?;
 match version {
 // 64 bit creation and modification times.
 1 => {
 skip(src, 16)?;
 }
 // 32 bit creation and modification times.
 0 => {
 skip(src, 8)?;
 }
 _ => return Status::MvhdBadVersion.into(),
 }
 let timescale = be_u32(src)?;
 let duration = match version {
 1 => be_u64(src)?,
 0 => {
 let d = be_u32(src)?;
 if d == std::u32::MAX {
 std::u64::MAX
 } else {
 u64::from(d)
 }
 }
 _ => unreachable!("Should have returned Status::MvhdBadVersion"),
 };
 // Skip remaining valid fields.
 skip(src, 80)?;

 // Padding could be added in some contents.
 skip_box_remain(src)?;
 Ok(MovieHeaderBox {
 timescale,
 duration,
 })
}

/// Parse a tkhd box.
fn read_tkhd<T: Read>(src: &mut BMFFBox<T>) -> Result<TrackHeaderBox> {
 let (version, flags) = read_fullbox_extra(src)?;
 let disabled = flags & 0x1u32 == 0 || flags & 0x2u32 == 0;
 match version {
 // 64 bit creation and modification times.
 1 => {
 skip(src, 16)?;
 }
 // 32 bit creation and modification times.
 0 => {
 skip(src, 8)?;
 }
 _ => return Status::TkhdBadVersion.into(),
 }
 let track_id = be_u32(src)?;
 skip(src, 4)?;
 let duration = match version {
 1 => be_u64(src)?,
 0 => u64::from(be_u32(src)?),
 _ => unreachable!("Should have returned Status::TkhdBadVersion"),
 };
 // Skip uninteresting fields.
 skip(src, 16)?;

 let matrix = Matrix {
 a: be_i32(src)?,
 b: be_i32(src)?,
 u: be_i32(src)?,
 c: be_i32(src)?,
 d: be_i32(src)?,
 v: be_i32(src)?,
 x: be_i32(src)?,
 y: be_i32(src)?,
 w: be_i32(src)?,
 };

 let width = be_u32(src)?;
 let height = be_u32(src)?;
 Ok(TrackHeaderBox {
 track_id,
 disabled,
 duration,
 width,
 height,
 matrix,
 })
}

/// Parse a elst box.
/// See ISOBMFF (ISO 14496-12:2020) § 8.6.6
fn read_elst<T: Read>(src: &mut BMFFBox<T>) -> Result<EditListBox> {
 let (version, flags) = read_fullbox_extra(src)?;
 let edit_count = be_u32(src)?;
 let mut edits = TryVec::with_capacity(edit_count.to_usize())?;
 for _ in 0..edit_count {
 let (segment_duration, media_time) = match version {
 1 => {
 // 64 bit segment duration and media times.
 (be_u64(src)?, be_i64(src)?)
 }
 0 => {
 // 32 bit segment duration and media times.
 (u64::from(be_u32(src)?), i64::from(be_i32(src)?))
 }
 _ => return Status::ElstBadVersion.into(),
 };
 let media_rate_integer = be_i16(src)?;
 let media_rate_fraction = be_i16(src)?;
 edits.push(Edit {
 segment_duration,
 media_time,
 media_rate_integer,
 media_rate_fraction,
 })?;
 }

 // Padding could be added in some contents.
 skip_box_remain(src)?;

 Ok(EditListBox {
 looped: flags == 1,
 edits,
 })
}

/// Parse a mdhd box.
fn read_mdhd<T: Read>(src: &mut BMFFBox<T>) -> Result<MediaHeaderBox> {
 let (version, _) = read_fullbox_extra(src)?;
 let (timescale, duration) = match version {
 1 => {
 // Skip 64-bit creation and modification times.
 skip(src, 16)?;

 // 64 bit duration.
 (be_u32(src)?, be_u64(src)?)
 }
 0 => {
 // Skip 32-bit creation and modification times.
 skip(src, 8)?;

 // 32 bit duration.
 let timescale = be_u32(src)?;
 let duration = {
 // Since we convert the 32-bit duration to 64-bit by
 // upcasting, we need to preserve the special all-1s
 // ("unknown") case by hand.
 let d = be_u32(src)?;
 if d == std::u32::MAX {
 std::u64::MAX
 } else {
 u64::from(d)
 }
 };
 (timescale, duration)
 }
 _ => return Status::MdhdBadVersion.into(),
 };

 // Skip uninteresting fields.
 skip(src, 4)?;

 Ok(MediaHeaderBox {
 timescale,
 duration,
 })
}

/// Parse a stco box.
/// See ISOBMFF (ISO 14496-12:2020) § 8.7.5
fn read_stco<T: Read>(src: &mut BMFFBox<T>) -> Result<ChunkOffsetBox> {
 let (_, _) = read_fullbox_extra(src)?;
 let offset_count = be_u32(src)?;
 let mut offsets = TryVec::with_capacity(offset_count.to_usize())?;
 for _ in 0..offset_count {
 offsets.push(be_u32(src)?.into())?;
 }

 // Padding could be added in some contents.
 skip_box_remain(src)?;

 Ok(ChunkOffsetBox { offsets })
}

/// Parse a co64 box.
/// See ISOBMFF (ISO 14496-12:2020) § 8.7.5
fn read_co64<T: Read>(src: &mut BMFFBox<T>) -> Result<ChunkOffsetBox> {
 let (_, _) = read_fullbox_extra(src)?;
 let offset_count = be_u32(src)?;
 let mut offsets = TryVec::with_capacity(offset_count.to_usize())?;
 for _ in 0..offset_count {
 offsets.push(be_u64(src)?)?;
 }

 // Padding could be added in some contents.
 skip_box_remain(src)?;

 Ok(ChunkOffsetBox { offsets })
}

/// Parse a stss box.
/// See ISOBMFF (ISO 14496-12:2020) § 8.6.2
fn read_stss<T: Read>(src: &mut BMFFBox<T>) -> Result<SyncSampleBox> {
 let (_, _) = read_fullbox_extra(src)?;
 let sample_count = be_u32(src)?;
 let mut samples = TryVec::with_capacity(sample_count.to_usize())?;
 for _ in 0..sample_count {
 samples.push(be_u32(src)?)?;
 }

 // Padding could be added in some contents.
 skip_box_remain(src)?;

 Ok(SyncSampleBox { samples })
}

/// Parse a stsc box.
/// See ISOBMFF (ISO 14496-12:2020) § 8.7.4
fn read_stsc<T: Read>(src: &mut BMFFBox<T>) -> Result<SampleToChunkBox> {
 let (_, _) = read_fullbox_extra(src)?;
 let sample_count = be_u32(src)?;
 let mut samples = TryVec::with_capacity(sample_count.to_usize())?;
 for _ in 0..sample_count {
 let first_chunk = be_u32(src)?;
 let samples_per_chunk = be_u32(src)?;
 let sample_description_index = be_u32(src)?;
 samples.push(SampleToChunk {
 first_chunk,
 samples_per_chunk,
 sample_description_index,
 })?;
 }

 // Padding could be added in some contents.
 skip_box_remain(src)?;

 Ok(SampleToChunkBox { samples })
}

/// Parse a Composition Time to Sample Box
/// See ISOBMFF (ISO 14496-12:2020) § 8.6.1.3
fn read_ctts<T: Read>(src: &mut BMFFBox<T>) -> Result<CompositionOffsetBox> {
 let (version, _) = read_fullbox_extra(src)?;

 let counts = be_u32(src)?;

 if counts
 .checked_mul(8)
 .map_or(true, |bytes| u64::from(bytes) > src.bytes_left())
 {
 return Status::CttsBadSize.into();
 }

 let mut offsets = TryVec::with_capacity(counts.to_usize())?;
 for _ in 0..counts {
 let (sample_count, time_offset) = match version {
 // According to spec, Version0 shoule be used when version == 0;
 // however, some buggy contents have negative value when version == 0.
 // So we always use Version1 here.
 0..=1 => {
 let count = be_u32(src)?;
 let offset = TimeOffsetVersion::Version1(be_i32(src)?);
 (count, offset)
 }
 _ => {
 return Status::CttsBadVersion.into();
 }
 };
 offsets.push(TimeOffset {
 sample_count,
 time_offset,
 })?;
 }

 check_parser_state!(src.content);

 Ok(CompositionOffsetBox { samples: offsets })
}

/// Parse a stsz box.
/// See ISOBMFF (ISO 14496-12:2020) § 8.7.3.2
fn read_stsz<T: Read>(src: &mut BMFFBox<T>) -> Result<SampleSizeBox> {
 let (_, _) = read_fullbox_extra(src)?;
 let sample_size = be_u32(src)?;
 let sample_count = be_u32(src)?;
 let mut sample_sizes = TryVec::new();
 if sample_size == 0 {
 sample_sizes.reserve(sample_count.to_usize())?;
 for _ in 0..sample_count {
 sample_sizes.push(be_u32(src)?)?;
 }
 }

 // Padding could be added in some contents.
 skip_box_remain(src)?;

 Ok(SampleSizeBox {
 sample_size,
 sample_sizes,
 })
}

/// Parse a stts box.
/// See ISOBMFF (ISO 14496-12:2020) § 8.6.1.2
fn read_stts<T: Read>(src: &mut BMFFBox<T>) -> Result<TimeToSampleBox> {
 let (_, _) = read_fullbox_extra(src)?;
 let sample_count = be_u32(src)?;
 let mut samples = TryVec::with_capacity(sample_count.to_usize())?;
 for _ in 0..sample_count {
 let sample_count = be_u32(src)?;
 let sample_delta = be_u32(src)?;
 samples.push(Sample {
 sample_count,
 sample_delta,
 })?;
 }

 // Padding could be added in some contents.
 skip_box_remain(src)?;

 Ok(TimeToSampleBox { samples })
}

/// Parse a VPx Config Box.
fn read_vpcc<T: Read>(src: &mut BMFFBox<T>) -> Result<VPxConfigBox> {
 let (version, _) = read_fullbox_extra(src)?;
 let supported_versions = [0, 1];
 if !supported_versions.contains(&version) {
 return Err(Error::Unsupported("unknown vpcC version"));
 }

 let profile = src.read_u8()?;
 let level = src.read_u8()?;
 let (
 bit_depth,
 colour_primaries,
 chroma_subsampling,
 transfer_characteristics,
 matrix_coefficients,
 video_full_range_flag,
 ) = if version == 0 {
 let (bit_depth, colour_primaries) = {
 let byte = src.read_u8()?;
 ((byte >> 4) & 0x0f, byte & 0x0f)
 };
 // Note, transfer_characteristics was known as transfer_function in v0
 let (chroma_subsampling, transfer_characteristics, video_full_range_flag) = {
 let byte = src.read_u8()?;
 ((byte >> 4) & 0x0f, (byte >> 1) & 0x07, (byte & 1) == 1)
 };
 (
 bit_depth,
 colour_primaries,
 chroma_subsampling,
 transfer_characteristics,
 None,
 video_full_range_flag,
 )
 } else {
 let (bit_depth, chroma_subsampling, video_full_range_flag) = {
 let byte = src.read_u8()?;
 ((byte >> 4) & 0x0f, (byte >> 1) & 0x07, (byte & 1) == 1)
 };
 let colour_primaries = src.read_u8()?;
 let transfer_characteristics = src.read_u8()?;
 let matrix_coefficients = src.read_u8()?;

 (
 bit_depth,
 colour_primaries,
 chroma_subsampling,
 transfer_characteristics,
 Some(matrix_coefficients),
 video_full_range_flag,
 )
 };

 let codec_init_size = be_u16(src)?;
 let codec_init = read_buf(src, codec_init_size.into())?;

 // TODO(rillian): validate field value ranges.
 Ok(VPxConfigBox {
 profile,
 level,
 bit_depth,
 colour_primaries,
 chroma_subsampling,
 transfer_characteristics,
 matrix_coefficients,
 video_full_range_flag,
 codec_init,
 })
}

/// See [AV1-ISOBMFF § 2.3.3](https://aomediacodec.github.io/av1-isobmff/#av1codecconfigurationbox-syntax)
fn read_av1c<T: Read>(src: &mut BMFFBox<T>) -> Result<AV1ConfigBox> {
 // We want to store the raw config as well as a structured (parsed) config, so create a copy of
 // the raw config so we have it later, and then parse the structured data from that.
 let raw_config = src.read_into_try_vec()?;
 let mut raw_config_slice = raw_config.as_slice();
 let marker_byte = raw_config_slice.read_u8()?;
 if marker_byte & 0x80 != 0x80 {
 return Err(Error::Unsupported("missing av1C marker bit"));
 }
 if marker_byte & 0x7f != 0x01 {
 return Err(Error::Unsupported("missing av1C marker bit"));
 }
 let profile_byte = raw_config_slice.read_u8()?;
 let profile = (profile_byte & 0xe0) >> 5;
 let level = profile_byte & 0x1f;
 let flags_byte = raw_config_slice.read_u8()?;
 let tier = (flags_byte & 0x80) >> 7;
 let bit_depth = match flags_byte & 0x60 {
 0x60 => 12,
 0x40 => 10,
 _ => 8,
 };
 let monochrome = flags_byte & 0x10 == 0x10;
 let chroma_subsampling_x = (flags_byte & 0x08) >> 3;
 let chroma_subsampling_y = (flags_byte & 0x04) >> 2;
 let chroma_sample_position = flags_byte & 0x03;
 let delay_byte = raw_config_slice.read_u8()?;
 let initial_presentation_delay_present = (delay_byte & 0x10) == 0x10;
 let initial_presentation_delay_minus_one = if initial_presentation_delay_present {
 delay_byte & 0x0f
 } else {
 0
 };

 Ok(AV1ConfigBox {
 profile,
 level,
 tier,
 bit_depth,
 monochrome,
 chroma_subsampling_x,
 chroma_subsampling_y,
 chroma_sample_position,
 initial_presentation_delay_present,
 initial_presentation_delay_minus_one,
 raw_config,
 })
}

fn read_flac_metadata<T: Read>(src: &mut BMFFBox<T>) -> Result<FLACMetadataBlock> {
 let temp = src.read_u8()?;
 let block_type = temp & 0x7f;
 let length = be_u24(src)?.into();
 if length > src.bytes_left() {
 return Status::DflaBadMetadataBlockSize.into();
 }
 let data = read_buf(src, length)?;
 Ok(FLACMetadataBlock { block_type, data })
}

/// See MPEG-4 Systems (ISO 14496-1:2010) § 7.2.6.5
fn find_descriptor(data: &[u8], esds: &mut ES_Descriptor) -> Result<()> {
 // Tags for elementary stream description
 const ESDESCR_TAG: u8 = 0x03;
 const DECODER_CONFIG_TAG: u8 = 0x04;
 const DECODER_SPECIFIC_TAG: u8 = 0x05;

 let mut remains = data;

 // Descriptor length should be more than 2 bytes.
 while remains.len() > 2 {
 let des = &mut Cursor::new(remains);
 let tag = des.read_u8()?;

 // See MPEG-4 Systems (ISO 14496-1:2010) § 8.3.3 for interpreting size of expandable classes

 let mut end: u32 = 0; // It's u8 without declaration type that is incorrect.
 // MSB of extend_or_len indicates more bytes, up to 4 bytes.
 for _ in 0..4 {
 if des.position() == remains.len().to_u64() {
 // There's nothing more to read, the 0x80 was actually part of
 // the content, and not an extension size.
 end = des.position() as u32;
 break;
 }
 let extend_or_len = des.read_u8()?;
 end = (end << 7) + u32::from(extend_or_len & 0x7F);
 if (extend_or_len & 0b1000_0000) == 0 {
 end += des.position() as u32;
 break;
 }
 }

 if end.to_usize() > remains.len() || u64::from(end) < des.position() {
 return Status::EsdsBadDescriptor.into();
 }

 let descriptor = &remains[des.position().try_into()?..end.to_usize()];

 match tag {
 ESDESCR_TAG => {
 read_es_descriptor(descriptor, esds)?;
 }
 DECODER_CONFIG_TAG => {
 read_dc_descriptor(descriptor, esds)?;
 }
 DECODER_SPECIFIC_TAG => {
 read_ds_descriptor(descriptor, esds)?;
 }
 _ => {
 debug!("Unsupported descriptor, tag {}", tag);
 }
 }

 remains = &remains[end.to_usize()..remains.len()];
 debug!("remains.len(): {}", remains.len());
 }

 Ok(())
}

fn get_audio_object_type(bit_reader: &mut BitReader) -> Result<u16> {
 let mut audio_object_type: u16 = ReadInto::read(bit_reader, 5)?;

 // Extend audio object type, for example, HE-AAC.
 if audio_object_type == 31 {
 let audio_object_type_ext: u16 = ReadInto::read(bit_reader, 6)?;
 audio_object_type = 32 + audio_object_type_ext;
 }
 Ok(audio_object_type)
}

/// See MPEG-4 Systems (ISO 14496-1:2010) § 7.2.6.7 and probably 14496-3 somewhere?
fn read_ds_descriptor(data: &[u8], esds: &mut ES_Descriptor) -> Result<()> {
 #[cfg(feature = "mp4v")]
 // Check if we are in a Visual esda Box.
 if esds.video_codec != CodecType::Unknown {
 esds.decoder_specific_data.extend_from_slice(data)?;
 return Ok(());
 }

 // We are in an Audio esda Box.
 let frequency_table = [
 (0x0, 96000),
 (0x1, 88200),
 (0x2, 64000),
 (0x3, 48000),
 (0x4, 44100),
 (0x5, 32000),
 (0x6, 24000),
 (0x7, 22050),
 (0x8, 16000),
 (0x9, 12000),
 (0xa, 11025),
 (0xb, 8000),
 (0xc, 7350),
 ];

 let bit_reader = &mut BitReader::new(data);

 let mut audio_object_type = get_audio_object_type(bit_reader)?;

 let sample_index: u32 = ReadInto::read(bit_reader, 4)?;

 // Sample frequency could be from table, or retrieved from stream directly
 // if index is 0x0f.
 let sample_frequency = match sample_index {
 0x0F => Some(ReadInto::read(bit_reader, 24)?),
 _ => frequency_table
 .iter()
 .find(|item| item.0 == sample_index)
 .map(|x| x.1),
 };

 let channel_configuration: u16 = ReadInto::read(bit_reader, 4)?;

 let extended_audio_object_type = match audio_object_type {
 5 | 29 => Some(5),
 _ => None,
 };

 if audio_object_type == 5 || audio_object_type == 29 {
 // We have an explicit signaling for BSAC extension, should the decoder
 // decode the BSAC extension (all Gecko's AAC decoders do), then this is
 // what the stream will actually look like once decoded.
 let _extended_sample_index = ReadInto::read(bit_reader, 4)?;
 let _extended_sample_frequency: Option<u32> = match _extended_sample_index {
 0x0F => Some(ReadInto::read(bit_reader, 24)?),
 _ => frequency_table
 .iter()
 .find(|item| item.0 == sample_index)
 .map(|x| x.1),
 };
 audio_object_type = get_audio_object_type(bit_reader)?;
 let _extended_channel_configuration = match audio_object_type {
 22 => ReadInto::read(bit_reader, 4)?,
 _ => channel_configuration,
 };
 };

 match audio_object_type {
 1..=4 | 6 | 7 | 17 | 19..=23 => {
 if sample_frequency.is_none() {
 return Err(Error::Unsupported("unknown frequency"));
 }

 // parsing GASpecificConfig

 // If the sampling rate is not one of the rates listed in the right
 // column in Table 4.82, the sampling frequency dependent tables
 // (code tables, scale factor band tables etc.) must be deduced in
 // order for the bitstream payload to be parsed. Since a given
 // sampling frequency is associated with only one sampling frequency
 // table, and since maximum flexibility is desired in the range of
 // possible sampling frequencies, the following table shall be used
 // to associate an implied sampling frequency with the desired
 // sampling frequency dependent tables.
 let sample_frequency_value = match sample_frequency.unwrap() {
 0..=9390 => 8000,
 9391..=11501 => 11025,
 11502..=13855 => 12000,
 13856..=18782 => 16000,
 18783..=23003 => 22050,
 23004..=27712 => 24000,
 27713..=37565 => 32000,
 37566..=46008 => 44100,
 46009..=55425 => 48000,
 55426..=75131 => 64000,
 75132..=92016 => 88200,
 _ => 96000,
 };

 bit_reader.skip(1)?; // frameLengthFlag
 let depend_on_core_order: u8 = ReadInto::read(bit_reader, 1)?;
 if depend_on_core_order > 0 {
 bit_reader.skip(14)?; // codeCoderDelay
 }
 bit_reader.skip(1)?; // extensionFlag

 let channel_counts = match channel_configuration {
 0 => {
 debug!("Parsing program_config_element for channel counts");

 bit_reader.skip(4)?; // element_instance_tag
 bit_reader.skip(2)?; // object_type
 bit_reader.skip(4)?; // sampling_frequency_index
 let num_front_channel: u8 = ReadInto::read(bit_reader, 4)?;
 let num_side_channel: u8 = ReadInto::read(bit_reader, 4)?;
 let num_back_channel: u8 = ReadInto::read(bit_reader, 4)?;
 let num_lfe_channel: u8 = ReadInto::read(bit_reader, 2)?;
 bit_reader.skip(3)?; // num_assoc_data
 bit_reader.skip(4)?; // num_valid_cc

 let mono_mixdown_present: bool = ReadInto::read(bit_reader, 1)?;
 if mono_mixdown_present {
 bit_reader.skip(4)?; // mono_mixdown_element_number
 }

 let stereo_mixdown_present: bool = ReadInto::read(bit_reader, 1)?;
 if stereo_mixdown_present {
 bit_reader.skip(4)?; // stereo_mixdown_element_number
 }

 let matrix_mixdown_idx_present: bool = ReadInto::read(bit_reader, 1)?;
 if matrix_mixdown_idx_present {
 bit_reader.skip(2)?; // matrix_mixdown_idx
 bit_reader.skip(1)?; // pseudo_surround_enable
 }
 let mut _channel_counts = 0;
 _channel_counts += read_surround_channel_count(bit_reader, num_front_channel)?;
 _channel_counts += read_surround_channel_count(bit_reader, num_side_channel)?;
 _channel_counts += read_surround_channel_count(bit_reader, num_back_channel)?;
 _channel_counts += read_surround_channel_count(bit_reader, num_lfe_channel)?;
 _channel_counts
 }
 1..=7 => channel_configuration,
 // Amendment 4 of the AAC standard in 2013 below
 11 => 7, // 6.1 Amendment 4 of the AAC standard in 2013
 12 | 14 => 8, // 7.1 (a/d) of ITU BS.2159
 _ => {
 return Err(Error::Unsupported("invalid channel configuration"));
 }
 };

 esds.audio_object_type = Some(audio_object_type);
 esds.extended_audio_object_type = extended_audio_object_type;
 esds.audio_sample_rate = Some(sample_frequency_value);
 esds.audio_channel_count = Some(channel_counts);
 if !esds.decoder_specific_data.is_empty() {
 return Status::EsdsDecSpecificIntoTagQuantity.into();
 }
 esds.decoder_specific_data.extend_from_slice(data)?;

 Ok(())
 }
 _ => Err(Error::Unsupported("unknown aac audio object type")),
 }
}

fn read_surround_channel_count(bit_reader: &mut BitReader, channels: u8) -> Result<u16> {
 let mut count = 0;
 for _ in 0..channels {
 let is_cpe: bool = ReadInto::read(bit_reader, 1)?;
 count += if is_cpe { 2 } else { 1 };
 bit_reader.skip(4)?;
 }
 Ok(count)
}

/// See MPEG-4 Systems (ISO 14496-1:2010) § 7.2.6.6
fn read_dc_descriptor(data: &[u8], esds: &mut ES_Descriptor) -> Result<()> {
 let des = &mut Cursor::new(data);
 let object_profile = des.read_u8()?;

 #[cfg(feature = "mp4v")]
 {
 esds.video_codec = match object_profile {
 0x20..=0x24 => CodecType::MP4V,
 _ => CodecType::Unknown,
 };
 }

 // Skip uninteresting fields.
 skip(des, 12)?;

 if data.len().to_u64() > des.position() {
 find_descriptor(&data[des.position().try_into()?..data.len()], esds)?;
 }

 esds.audio_codec = match object_profile {
 0x40 | 0x66 | 0x67 => CodecType::AAC,
 0x69 | 0x6B => CodecType::MP3,
 _ => CodecType::Unknown,
 };

 debug!(
 "read_dc_descriptor: esds.audio_codec = {:?}",
 esds.audio_codec
 );

 Ok(())
}

/// See MPEG-4 Systems (ISO 14496-1:2010) § 7.2.6.5
fn read_es_descriptor(data: &[u8], esds: &mut ES_Descriptor) -> Result<()> {
 let des = &mut Cursor::new(data);

 skip(des, 2)?;

 let esds_flags = des.read_u8()?;

 // Stream dependency flag, first bit from left most.
 if esds_flags & 0x80 > 0 {
 // Skip uninteresting fields.
 skip(des, 2)?;
 }

 // Url flag, second bit from left most.
 if esds_flags & 0x40 > 0 {
 // Skip uninteresting fields.
 let skip_es_len = u64::from(des.read_u8()?) + 2;
 skip(des, skip_es_len)?;
 }

 if data.len().to_u64() > des.position() {
 find_descriptor(&data[des.position().try_into()?..data.len()], esds)?;
 }

 Ok(())
}

/// See MP4 (ISO 14496-14:2020) § 6.7.2
fn read_esds<T: Read>(src: &mut BMFFBox<T>) -> Result<ES_Descriptor> {
 let (_, _) = read_fullbox_extra(src)?;

 let esds_array = read_buf(src, src.bytes_left())?;

 let mut es_data = ES_Descriptor::default();
 find_descriptor(&esds_array, &mut es_data)?;

 es_data.codec_esds = esds_array;

 Ok(es_data)
}

/// Parse `FLACSpecificBox`.
/// See [Encapsulation of FLAC in ISO Base Media File Format](https://github.com/xiph/flac/blob/master/doc/isoflac.txt) § 3.3.2
fn read_dfla<T: Read>(src: &mut BMFFBox<T>) -> Result<FLACSpecificBox> {
 let (version, flags) = read_fullbox_extra(src)?;
 if version != 0 {
 return Err(Error::Unsupported("unknown dfLa (FLAC) version"));
 }
 if flags != 0 {
 return Status::DflaFlagsNonzero.into();
 }
 let mut blocks = TryVec::new();
 while src.bytes_left() > 0 {
 let block = read_flac_metadata(src)?;
 blocks.push(block)?;
 }
 // The box must have at least one meta block, and the first block
 // must be the METADATA_BLOCK_STREAMINFO
 if blocks.is_empty() {
 return Status::DflaMissingMetadata.into();
 } else if blocks[0].block_type != 0 {
 return Status::DflaStreamInfoNotFirst.into();
 } else if blocks[0].data.len() != 34 {
 return Status::DflaStreamInfoBadSize.into();
 }
 Ok(FLACSpecificBox { version, blocks })
}

/// Parse `OpusSpecificBox`.
fn read_dops<T: Read>(src: &mut BMFFBox<T>) -> Result<OpusSpecificBox> {
 let version = src.read_u8()?;
 if version != 0 {
 return Err(Error::Unsupported("unknown dOps (Opus) version"));
 }

 let output_channel_count = src.read_u8()?;
 let pre_skip = be_u16(src)?;
 let input_sample_rate = be_u32(src)?;
 let output_gain = be_i16(src)?;
 let channel_mapping_family = src.read_u8()?;

 let channel_mapping_table = if channel_mapping_family == 0 {
 None
 } else {
 let stream_count = src.read_u8()?;
 let coupled_count = src.read_u8()?;
 let channel_mapping = read_buf(src, output_channel_count.into())?;

 Some(ChannelMappingTable {
 stream_count,
 coupled_count,
 channel_mapping,
 })
 };

 // TODO(kinetik): validate field value ranges.
 Ok(OpusSpecificBox {
 version,
 output_channel_count,
 pre_skip,
 input_sample_rate,
 output_gain,
 channel_mapping_family,
 channel_mapping_table,
 })
}

/// Re-serialize the Opus codec-specific config data as an `OpusHead` packet.
///
/// Some decoders expect the initialization data in the format used by the
/// Ogg and WebM encapsulations. To support this we prepend the `OpusHead`
/// tag and byte-swap the data from big- to little-endian relative to the
/// dOps box.
pub fn serialize_opus_header<W: byteorder::WriteBytesExt + std::io::Write>(
 opus: &OpusSpecificBox,
 dst: &mut W,
) -> Result<()> {
 match dst.write(b"OpusHead") {
 Err(e) => return Err(Error::from(e)),
 Ok(bytes) => {
 if bytes != 8 {
 return Status::DopsOpusHeadWriteErr.into();
 }
 }
 }
 // In mp4 encapsulation, the version field is 0, but in ogg
 // it is 1. While decoders generally accept zero as well, write
 // out the version of the header we're supporting rather than
 // whatever we parsed out of mp4.
 dst.write_u8(1)?;
 dst.write_u8(opus.output_channel_count)?;
 dst.write_u16::<byteorder::LittleEndian>(opus.pre_skip)?;
 dst.write_u32::<byteorder::LittleEndian>(opus.input_sample_rate)?;
 dst.write_i16::<byteorder::LittleEndian>(opus.output_gain)?;
 dst.write_u8(opus.channel_mapping_family)?;
 match opus.channel_mapping_table {
 None => {}
 Some(ref table) => {
 dst.write_u8(table.stream_count)?;
 dst.write_u8(table.coupled_count)?;
 match dst.write(&table.channel_mapping) {
 Err(e) => return Err(Error::from(e)),
 Ok(bytes) => {
 if bytes != table.channel_mapping.len() {
 return Status::DopsChannelMappingWriteErr.into();
 }
 }
 }
 }
 };
 Ok(())
}

/// Parse `ALACSpecificBox`.
fn read_alac<T: Read>(src: &mut BMFFBox<T>) -> Result<ALACSpecificBox> {
 let (version, flags) = read_fullbox_extra(src)?;
 if version != 0 {
 return Err(Error::Unsupported("unknown alac (ALAC) version"));
 }
 if flags != 0 {
 return Status::AlacFlagsNonzero.into();
 }

 let length = match src.bytes_left() {
 x @ 24 | x @ 48 => x,
 _ => {
 return Status::AlacBadMagicCookieSize.into();
 }
 };
 let data = read_buf(src, length)?;

 Ok(ALACSpecificBox { version, data })
}

/// Parse a Handler Reference Box. 
/// See ISOBMFF (ISO 14496-12:2020) § 8.4.3 
/// See [\[ISOBMFF\]: reserved (field = 0;) handling is ambiguous](https://github.com/MPEGGroup/FileFormat/issues/36)
fn read_hdlr<T: Read>(src: &mut BMFFBox<T>, strictness: ParseStrictness) -> Result<HandlerBox> {
 if read_fullbox_version_no_flags(src)? != 0 {
 return Status::HdlrUnsupportedVersion.into();
 }

 let pre_defined = be_u32(src)?;
 if pre_defined != 0 {
 fail_with_status_if(
 strictness == ParseStrictness::Strict,
 Status::HdlrPredefinedNonzero,
 )?;
 }

 let handler_type = FourCC::from(be_u32(src)?);

 for _ in 1..=3 {
 let reserved = be_u32(src)?;
 if reserved != 0 {
 fail_with_status_if(
 strictness == ParseStrictness::Strict,
 Status::HdlrReservedNonzero,
 )?;
 }
 }

 match std::str::from_utf8(src.read_into_try_vec()?.as_slice()) {
 Ok(name) => {
 match name.bytes().position(|b| b == b'\0') {
 None => fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::HdlrNameNoNul,
 )?,
 // `name` must be nul-terminated and any trailing bytes after the first nul ignored.
 // See https://github.com/MPEGGroup/FileFormat/issues/35
 Some(_) => (),
 }
 }
 Err(_) => fail_with_status_if(
 strictness != ParseStrictness::Permissive,
 Status::HdlrNameNotUtf8,
 )?,
 }

 Ok(HandlerBox { handler_type })
}

/// Parse an video description inside an stsd box.
fn read_video_sample_entry<T: Read>(src: &mut BMFFBox<T>) -> Result<SampleEntry> {
 let name = src.get_header().name;
 let codec_type = match name {
 BoxType::AVCSampleEntry | BoxType::AVC3SampleEntry => CodecType::H264,
 BoxType::MP4VideoSampleEntry => CodecType::MP4V,
 BoxType::VP8SampleEntry => CodecType::VP8,
 BoxType::VP9SampleEntry => CodecType::VP9,
 BoxType::AV1SampleEntry => CodecType::AV1,
 BoxType::ProtectedVisualSampleEntry => CodecType::EncryptedVideo,
 BoxType::H263SampleEntry => CodecType::H263,
 BoxType::HEV1SampleEntry | BoxType::HVC1SampleEntry => CodecType::HEVC,
 _ => {
 debug!("Unsupported video codec, box {:?} found", name);
 CodecType::Unknown
 }
 };

 // Skip uninteresting fields.
 skip(src, 6)?;

 let data_reference_index = be_u16(src)?;

 // Skip uninteresting fields.
 skip(src, 16)?;

 let width = be_u16(src)?;
 let height = be_u16(src)?;

 // Skip uninteresting fields.
 skip(src, 50)?;

 // Skip clap/pasp/etc. for now.
 let mut codec_specific = None;
 let mut protection_info = TryVec::new();
 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::AVCConfigurationBox => {
 if (name != BoxType::AVCSampleEntry
 && name != BoxType::AVC3SampleEntry
 && name != BoxType::ProtectedVisualSampleEntry)
 || codec_specific.is_some()
 {
 return Status::StsdBadVideoSampleEntry.into();
 }
 let avcc_size = b
 .head
 .size
 .checked_sub(b.head.offset)
 .expect("offset invalid");
 let avcc = read_buf(&mut b.content, avcc_size)?;
 debug!("{:?} (avcc)", avcc);
 // TODO(kinetik): Parse avcC box? For now we just stash the data.
 codec_specific = Some(VideoCodecSpecific::AVCConfig(avcc));
 }
 BoxType::H263SpecificBox => {
 if (name != BoxType::H263SampleEntry) || codec_specific.is_some() {
 return Status::StsdBadVideoSampleEntry.into();
 }
 let h263_dec_spec_struc_size = b
 .head
 .size
 .checked_sub(b.head.offset)
 .expect("offset invalid");
 let h263_dec_spec_struc = read_buf(&mut b.content, h263_dec_spec_struc_size)?;
 debug!("{:?} (h263DecSpecStruc)", h263_dec_spec_struc);

 codec_specific = Some(VideoCodecSpecific::H263Config(h263_dec_spec_struc));
 }
 BoxType::VPCodecConfigurationBox => {
 // vpcC
 if (name != BoxType::VP8SampleEntry
 && name != BoxType::VP9SampleEntry
 && name != BoxType::ProtectedVisualSampleEntry)
 || codec_specific.is_some()
 {
 return Status::StsdBadVideoSampleEntry.into();
 }
 let vpcc = read_vpcc(&mut b)?;
 codec_specific = Some(VideoCodecSpecific::VPxConfig(vpcc));
 }
 BoxType::AV1CodecConfigurationBox => {
 if name != BoxType::AV1SampleEntry && name != BoxType::ProtectedVisualSampleEntry {
 return Status::StsdBadVideoSampleEntry.into();
 }
 let av1c = read_av1c(&mut b)?;
 codec_specific = Some(VideoCodecSpecific::AV1Config(av1c));
 }
 BoxType::ESDBox => {
 if name != BoxType::MP4VideoSampleEntry || codec_specific.is_some() {
 return Status::StsdBadVideoSampleEntry.into();
 }
 #[cfg(not(feature = "mp4v"))]
 {
 let (_, _) = read_fullbox_extra(&mut b.content)?;
 // Subtract 4 extra to offset the members of fullbox not
 // accounted for in head.offset
 let esds_size = b
 .head
 .size
 .checked_sub(b.head.offset + 4)
 .expect("offset invalid");
 let esds = read_buf(&mut b.content, esds_size)?;
 codec_specific = Some(VideoCodecSpecific::ESDSConfig(esds));
 }
 #[cfg(feature = "mp4v")]
 {
 // Read ES_Descriptor inside an esds box.
 // See ISOBMFF (ISO 14496-1:2010) § 7.2.6.5
 let esds = read_esds(&mut b)?;
 codec_specific =
 Some(VideoCodecSpecific::ESDSConfig(esds.decoder_specific_data));
 }
 }
 BoxType::ProtectionSchemeInfoBox => {
 if name != BoxType::ProtectedVisualSampleEntry {
 return Status::StsdBadVideoSampleEntry.into();
 }
 let sinf = read_sinf(&mut b)?;
 debug!("{:?} (sinf)", sinf);
 protection_info.push(sinf)?;
 }
 BoxType::HEVCConfigurationBox => {
 if (name != BoxType::HEV1SampleEntry
 && name != BoxType::HVC1SampleEntry
 && name != BoxType::ProtectedVisualSampleEntry)
 || codec_specific.is_some()
 {
 return Status::StsdBadVideoSampleEntry.into();
 }
 let hvcc_size = b
 .head
 .size
 .checked_sub(b.head.offset)
 .expect("offset invalid");
 let hvcc = read_buf(&mut b.content, hvcc_size)?;
 debug!("{:?} (hvcc)", hvcc);
 codec_specific = Some(VideoCodecSpecific::HEVCConfig(hvcc));
 }
 _ => {
 debug!("Unsupported video codec, box {:?} found", b.head.name);
 skip_box_content(&mut b)?;
 }
 }
 check_parser_state!(b.content);
 }

 Ok(
 codec_specific.map_or(SampleEntry::Unknown, |codec_specific| {
 SampleEntry::Video(VideoSampleEntry {
 codec_type,
 data_reference_index,
 width,
 height,
 codec_specific,
 protection_info,
 })
 }),
 )
}

fn read_qt_wave_atom<T: Read>(src: &mut BMFFBox<T>) -> Result<ES_Descriptor> {
 let mut codec_specific = None;
 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::ESDBox => {
 let esds = read_esds(&mut b)?;
 codec_specific = Some(esds);
 }
 _ => skip_box_content(&mut b)?,
 }
 }

 codec_specific.ok_or_else(|| Error::from(Status::EsdsBadAudioSampleEntry))
}

/// Parse an audio description inside an stsd box.
/// See ISOBMFF (ISO 14496-12:2020) § 12.2.3
fn read_audio_sample_entry<T: Read>(src: &mut BMFFBox<T>) -> Result<SampleEntry> {
 let name = src.get_header().name;

 // Skip uninteresting fields.
 skip(src, 6)?;

 let data_reference_index = be_u16(src)?;

 // XXX(kinetik): This is "reserved" in BMFF, but some old QT MOV variant
 // uses it, need to work out if we have to support it. Without checking
 // here and reading extra fields after samplerate (or bailing with an
 // error), the parser loses sync completely.
 let version = be_u16(src)?;

 // Skip uninteresting fields.
 skip(src, 6)?;

 let mut channelcount = u32::from(be_u16(src)?);
 let samplesize = be_u16(src)?;

 // Skip uninteresting fields.
 skip(src, 4)?;

 let mut samplerate = f64::from(be_u32(src)? >> 16); // 16.16 fixed point;

 match version {
 0 => (),
 1 => {
 // Quicktime sound sample description version 1.
 // Skip uninteresting fields.
 skip(src, 16)?;
 }
 2 => {
 // Quicktime sound sample description version 2.
 skip(src, 4)?;
 samplerate = f64::from_bits(be_u64(src)?);
 channelcount = be_u32(src)?;
 skip(src, 20)?;
 }
 _ => {
 return Err(Error::Unsupported(
 "unsupported non-isom audio sample entry",
 ))
 }
 }

 let (mut codec_type, mut codec_specific) = match name {
 BoxType::MP3AudioSampleEntry => (CodecType::MP3, Some(AudioCodecSpecific::MP3)),
 BoxType::LPCMAudioSampleEntry => (CodecType::LPCM, Some(AudioCodecSpecific::LPCM)),
 // Some mp4 file with AMR doesn't have AMRSpecificBox "damr" in followed while loop,
 // we use empty box by default.
 #[cfg(feature = "3gpp")]
 BoxType::AMRNBSampleEntry => (
 CodecType::AMRNB,
 Some(AudioCodecSpecific::AMRSpecificBox(Default::default())),
 ),
 #[cfg(feature = "3gpp")]
 BoxType::AMRWBSampleEntry => (
 CodecType::AMRWB,
 Some(AudioCodecSpecific::AMRSpecificBox(Default::default())),
 ),
 _ => (CodecType::Unknown, None),
 };
 let mut protection_info = TryVec::new();
 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::ESDBox => {
 if (name != BoxType::MP4AudioSampleEntry
 && name != BoxType::ProtectedAudioSampleEntry)
 || codec_specific.is_some()
 {
 return Status::StsdBadAudioSampleEntry.into();
 }
 let esds = read_esds(&mut b)?;
 codec_type = esds.audio_codec;
 codec_specific = Some(AudioCodecSpecific::ES_Descriptor(esds));
 }
 BoxType::FLACSpecificBox => {
 if (name != BoxType::FLACSampleEntry && name != BoxType::ProtectedAudioSampleEntry)
 || codec_specific.is_some()
 {
 return Status::StsdBadAudioSampleEntry.into();
 }
 let dfla = read_dfla(&mut b)?;
 codec_type = CodecType::FLAC;
 codec_specific = Some(AudioCodecSpecific::FLACSpecificBox(dfla));
 }
 BoxType::OpusSpecificBox => {
 if (name != BoxType::OpusSampleEntry && name != BoxType::ProtectedAudioSampleEntry)
 || codec_specific.is_some()
 {
 return Status::StsdBadAudioSampleEntry.into();
 }
 let dops = read_dops(&mut b)?;
 codec_type = CodecType::Opus;
 codec_specific = Some(AudioCodecSpecific::OpusSpecificBox(dops));
 }
 BoxType::ALACSpecificBox => {
 if name != BoxType::ALACSpecificBox || codec_specific.is_some() {
 return Status::StsdBadAudioSampleEntry.into();
 }
 let alac = read_alac(&mut b)?;
 codec_type = CodecType::ALAC;
 codec_specific = Some(AudioCodecSpecific::ALACSpecificBox(alac));
 }
 BoxType::QTWaveAtom => {
 let qt_esds = read_qt_wave_atom(&mut b)?;
 codec_type = qt_esds.audio_codec;
 codec_specific = Some(AudioCodecSpecific::ES_Descriptor(qt_esds));
 }
 BoxType::ProtectionSchemeInfoBox => {
 if name != BoxType::ProtectedAudioSampleEntry {
 return Status::StsdBadAudioSampleEntry.into();
 }
 let sinf = read_sinf(&mut b)?;
 debug!("{:?} (sinf)", sinf);
 codec_type = CodecType::EncryptedAudio;
 protection_info.push(sinf)?;
 }
 #[cfg(feature = "3gpp")]
 BoxType::AMRSpecificBox => {
 if codec_type != CodecType::AMRNB && codec_type != CodecType::AMRWB {
 return Status::StsdBadAudioSampleEntry.into();
 }
 let amr_dec_spec_struc_size = b
 .head
 .size
 .checked_sub(b.head.offset)
 .expect("offset invalid");
 let amr_dec_spec_struc = read_buf(&mut b.content, amr_dec_spec_struc_size)?;
 debug!("{:?} (AMRDecSpecStruc)", amr_dec_spec_struc);
 codec_specific = Some(AudioCodecSpecific::AMRSpecificBox(amr_dec_spec_struc));
 }
 _ => {
 debug!("Unsupported audio codec, box {:?} found", b.head.name);
 skip_box_content(&mut b)?;
 }
 }
 check_parser_state!(b.content);
 }

 Ok(
 codec_specific.map_or(SampleEntry::Unknown, |codec_specific| {
 SampleEntry::Audio(AudioSampleEntry {
 codec_type,
 data_reference_index,
 channelcount,
 samplesize,
 samplerate,
 codec_specific,
 protection_info,
 })
 }),
 )
}

/// Parse a stsd box.
/// See ISOBMFF (ISO 14496-12:2020) § 8.5.2
/// See MP4 (ISO 14496-14:2020) § 6.7.2
fn read_stsd<T: Read>(src: &mut BMFFBox<T>, track: &Track) -> Result<SampleDescriptionBox> {
 let (_, flags) = read_fullbox_extra(src)?;

 if flags != 0 {
 warn!(
 "Unexpected `flags` value for SampleDescriptionBox (stsd): {}",
 flags
 );
 }

 let description_count = be_u32(src)?.to_usize();
 let mut descriptions = TryVec::with_capacity(description_count)?;

 let mut iter = src.box_iter();
 while descriptions.len() < description_count {
 if let Some(mut b) = iter.next_box()? {
 let description = match track.track_type {
 TrackType::Video => read_video_sample_entry(&mut b),
 TrackType::Picture => read_video_sample_entry(&mut b),
 TrackType::AuxiliaryVideo => read_video_sample_entry(&mut b),
 TrackType::Audio => read_audio_sample_entry(&mut b),
 TrackType::Metadata => Err(Error::Unsupported("metadata track")),
 TrackType::Unknown => Err(Error::Unsupported("unknown track type")),
 };
 let description = match description {
 Ok(desc) => desc,
 Err(Error::Unsupported(_)) => {
 // read_{audio,video}_desc may have returned Unsupported
 // after partially reading the box content, so we can't
 // simply use skip_box_content here.
 let to_skip = b.bytes_left();
 skip(&mut b, to_skip)?;
 SampleEntry::Unknown
 }
 Err(e) => return Err(e),
 };
 descriptions.push(description)?;
 check_parser_state!(b.content);
 } else {
 break;
 }
 }

 // Padding could be added in some contents.
 skip_box_remain(src)?;

 Ok(SampleDescriptionBox { descriptions })
}

fn read_sinf<T: Read>(src: &mut BMFFBox<T>) -> Result<ProtectionSchemeInfoBox> {
 let mut sinf = ProtectionSchemeInfoBox::default();

 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::OriginalFormatBox => {
 sinf.original_format = FourCC::from(be_u32(&mut b)?);
 }
 BoxType::SchemeTypeBox => {
 sinf.scheme_type = Some(read_schm(&mut b)?);
 }
 BoxType::SchemeInformationBox => {
 // We only need tenc box in schi box so far.
 sinf.tenc = read_schi(&mut b)?;
 }
 _ => skip_box_content(&mut b)?,
 }
 check_parser_state!(b.content);
 }

 Ok(sinf)
}

fn read_schi<T: Read>(src: &mut BMFFBox<T>) -> Result<Option<TrackEncryptionBox>> {
 let mut tenc = None;
 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::TrackEncryptionBox => {
 if tenc.is_some() {
 return Status::SchiQuantity.into();
 }
 tenc = Some(read_tenc(&mut b)?);
 }
 _ => skip_box_content(&mut b)?,
 }
 }

 Ok(tenc)
}

fn read_tenc<T: Read>(src: &mut BMFFBox<T>) -> Result<TrackEncryptionBox> {
 let (version, _) = read_fullbox_extra(src)?;

 // reserved byte
 skip(src, 1)?;
 // the next byte is used to signal the default pattern in version >= 1
 let (default_crypt_byte_block, default_skip_byte_block) = match version {
 0 => {
 skip(src, 1)?;
 (None, None)
 }
 _ => {
 let pattern_byte = src.read_u8()?;
 let crypt_bytes = pattern_byte >> 4;
 let skip_bytes = pattern_byte & 0x0f;
 (Some(crypt_bytes), Some(skip_bytes))
 }
 };
 let default_is_encrypted = src.read_u8()?;
 let default_iv_size = src.read_u8()?;
 let default_kid = read_buf(src, 16)?;
 // If default_is_encrypted == 1 && default_iv_size == 0 we expect a default_constant_iv
 let default_constant_iv = match (default_is_encrypted, default_iv_size) {
 (1, 0) => {
 let default_constant_iv_size = src.read_u8()?;
 Some(read_buf(src, default_constant_iv_size.into())?)
 }
 _ => None,
 };

 Ok(TrackEncryptionBox {
 is_encrypted: default_is_encrypted,
 iv_size: default_iv_size,
 kid: default_kid,
 crypt_byte_block_count: default_crypt_byte_block,
 skip_byte_block_count: default_skip_byte_block,
 constant_iv: default_constant_iv,
 })
}

fn read_schm<T: Read>(src: &mut BMFFBox<T>) -> Result<SchemeTypeBox> {
 // Flags can be used to signal presence of URI in the box, but we don't
 // use the URI so don't bother storing the flags.
 let (_, _) = read_fullbox_extra(src)?;
 let scheme_type = FourCC::from(be_u32(src)?);
 let scheme_version = be_u32(src)?;
 // Null terminated scheme URI may follow, but we don't use it right now.
 skip_box_remain(src)?;
 Ok(SchemeTypeBox {
 scheme_type,
 scheme_version,
 })
}

/// Parse a metadata box inside a moov, trak, or mdia box.
/// See ISOBMFF (ISO 14496-12:2020) § 8.10.1.
fn read_udta<T: Read>(src: &mut BMFFBox<T>) -> Result<UserdataBox> {
 let mut iter = src.box_iter();
 let mut udta = UserdataBox { meta: None };

 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::MetadataBox => {
 let meta = read_meta(&mut b)?;
 udta.meta = Some(meta);
 }
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(udta)
}

/// Parse the meta box
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.1
fn read_meta<T: Read>(src: &mut BMFFBox<T>) -> Result<MetadataBox> {
 let (_, _) = read_fullbox_extra(src)?;
 let mut iter = src.box_iter();
 let mut meta = MetadataBox::default();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::MetadataItemListEntry => read_ilst(&mut b, &'color:red'>mut meta)?,
 #[cfg(feature = "meta-xml")]
 BoxType::MetadataXMLBox => read_xml_(&mut b, &mut meta)?,
 #[cfg(feature = "meta-xml")]
 BoxType::MetadataBXMLBox => read_bxml(&mut b, &mut meta)?,
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(meta)
}

/// Parse a XML box inside a meta box
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.2
#[cfg(feature = "meta-xml")]
fn read_xml_<T: Read>(src: &mut BMFFBox<T>, meta: &mut MetadataBox) -> Result<()> {
 if read_fullbox_version_no_flags(src)? != 0 {
 return Err(Error::Unsupported("unsupported XmlBox version"));
 }
 meta.xml = Some(XmlBox::StringXmlBox(src.read_into_try_vec()?));
 Ok(())
}

/// Parse a Binary XML box inside a meta box
/// See ISOBMFF (ISO 14496-12:2020) § 8.11.2
#[cfg(feature = "meta-xml")]
fn read_bxml<T: Read>(src: &mut BMFFBox<T>, meta: &mut MetadataBox) -> Result<()> {
 if read_fullbox_version_no_flags(src)? != 0 {
 return Err(Error::Unsupported("unsupported XmlBox version"));
 }
 meta.xml = Some(XmlBox::BinaryXmlBox(src.read_into_try_vec()?));
 Ok(())
}

/// Parse a metadata box inside a udta box
fn read_ilst<T: Read>(src: &mut BMFFBox<T>, meta: &mut MetadataBox) -> Result<()> {
 let mut iter = src.box_iter();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::AlbumEntry => meta.album = read_ilst_string_data(&mut b)?,
 BoxType::ArtistEntry | BoxType::ArtistLowercaseEntry => {
 meta.artist = read_ilst_string_data(&mut b)?
 }
 BoxType::AlbumArtistEntry => meta.album_artist = read_ilst_string_data(&mut b)?,
 BoxType::CommentEntry => meta.comment = read_ilst_string_data(&mut b)?,
 BoxType::DateEntry => meta.year = read_ilst_string_data(&mut b)?,
 BoxType::TitleEntry => meta.title = read_ilst_string_data(&mut b)?,
 BoxType::CustomGenreEntry => {
 meta.genre = read_ilst_string_data(&mut b)?.map(Genre::CustomGenre)
 }
 BoxType::StandardGenreEntry => {
 meta.genre = read_ilst_u8_data(&mut b)?
 .and_then(|gnre| Some(Genre::StandardGenre(gnre.get(1).copied()?)))
 }
 BoxType::ComposerEntry => meta.composer = read_ilst_string_data(&mut b)?,
 BoxType::EncoderEntry => meta.encoder = read_ilst_string_data(&mut b)?,
 BoxType::EncodedByEntry => meta.encoded_by = read_ilst_string_data(&mut b)?,
 BoxType::CopyrightEntry => meta.copyright = read_ilst_string_data(&mut b)?,
 BoxType::GroupingEntry => meta.grouping = read_ilst_string_data(&mut b)?,
 BoxType::CategoryEntry => meta.category = read_ilst_string_data(&mut b)?,
 BoxType::KeywordEntry => meta.keyword = read_ilst_string_data(&mut b)?,
 BoxType::PodcastUrlEntry => meta.podcast_url = read_ilst_string_data(&mut b)?,
 BoxType::PodcastGuidEntry => meta.podcast_guid = read_ilst_string_data(&mut b)?,
 BoxType::DescriptionEntry => meta.description = read_ilst_string_data(&mut b)?,
 BoxType::LongDescriptionEntry => meta.long_description = read_ilst_string_data(&tyle='color:red'>mut b)?,
 BoxType::LyricsEntry => meta.lyrics = read_ilst_string_data(&mut b)?,
 BoxType::TVNetworkNameEntry => meta.tv_network_name = read_ilst_string_data(&e='color:red'>mut b)?,
 BoxType::TVEpisodeNameEntry => meta.tv_episode_name = read_ilst_string_data(&e='color:red'>mut b)?,
 BoxType::TVShowNameEntry => meta.tv_show_name = read_ilst_string_data(&mut b)?,
 BoxType::PurchaseDateEntry => meta.purchase_date = read_ilst_string_data(&mut b)?,
 BoxType::RatingEntry => meta.rating = read_ilst_string_data(&mut b)?,
 BoxType::OwnerEntry => meta.owner = read_ilst_string_data(&mut b)?,
 BoxType::HDVideoEntry => meta.hd_video = read_ilst_bool_data(&mut b)?,
 BoxType::SortNameEntry => meta.sort_name = read_ilst_string_data(&mut b)?,
 BoxType::SortArtistEntry => meta.sort_artist = read_ilst_string_data(&mut b)?,
 BoxType::SortAlbumEntry => meta.sort_album = read_ilst_string_data(&mut b)?,
 BoxType::SortAlbumArtistEntry => {
 meta.sort_album_artist = read_ilst_string_data(&mut b)?
 }
 BoxType::SortComposerEntry => meta.sort_composer = read_ilst_string_data(&mut b)?,
 BoxType::TrackNumberEntry => {
 if let Some(trkn) = read_ilst_u8_data(&mut b)? {
 meta.track_number = trkn.get(3).copied();
 meta.total_tracks = trkn.get(5).copied();
 };
 }
 BoxType::DiskNumberEntry => {
 if let Some(disk) = read_ilst_u8_data(&mut b)? {
 meta.disc_number = disk.get(3).copied();
 meta.total_discs = disk.get(5).copied();
 };
 }
 BoxType::TempoEntry => {
 meta.beats_per_minute =
 read_ilst_u8_data(&mut b)?.and_then(|tmpo| tmpo.get(1).copied())
 }
 BoxType::CompilationEntry => meta.compilation = read_ilst_bool_data(&mut b)?,
 BoxType::AdvisoryEntry => {
 meta.advisory = read_ilst_u8_data(&mut b)?.and_then(|rtng| {
 Some(match rtng.first()? {
 2 => AdvisoryRating::Clean,
 0 => AdvisoryRating::Inoffensive,
 r => AdvisoryRating::Explicit(*r),
 })
 })
 }
 BoxType::MediaTypeEntry => {
 meta.media_type = read_ilst_u8_data(&mut b)?.and_then(|stik| {
 Some(match stik.first()? {
 0 => MediaType::Movie,
 1 => MediaType::Normal,
 2 => MediaType::AudioBook,
 5 => MediaType::WhackedBookmark,
 6 => MediaType::MusicVideo,
 9 => MediaType::ShortFilm,
 10 => MediaType::TVShow,
 11 => MediaType::Booklet,
 s => MediaType::Unknown(*s),
 })
 })
 }
 BoxType::PodcastEntry => meta.podcast = read_ilst_bool_data(&mut b)?,
 BoxType::TVSeasonNumberEntry => {
 meta.tv_season = read_ilst_u8_data(&mut b)?.and_then(|tvsn| tvsn.get(3).copied())
 }
 BoxType::TVEpisodeNumberEntry => {
 meta.tv_episode_number =
 read_ilst_u8_data(&mut b)?.and_then(|tves| tves.get(3).copied())
 }
 BoxType::GaplessPlaybackEntry => meta.gapless_playback = read_ilst_bool_data(&le='color:red'>mut b)?,
 BoxType::CoverArtEntry => meta.cover_art = read_ilst_multiple_u8_data(&mut b).ok(),
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(())
}

fn read_ilst_bool_data<T: Read>(src: &mut BMFFBox<T>) -> Result<Option<bool>> {
 Ok(read_ilst_u8_data(src)?.and_then(|d| Some(d.first()? == &1)))
}

fn read_ilst_string_data<T: Read>(src: &mut BMFFBox<T>) -> Result<Option<TryString>> {
 read_ilst_u8_data(src)
}

fn read_ilst_u8_data<T: Read>(src: &mut BMFFBox<T>) -> Result<Option<TryVec<u8>>> {
 // For all non-covr atoms, there must only be one data atom.
 Ok(read_ilst_multiple_u8_data(src)?.pop())
}

fn read_ilst_multiple_u8_data<T: Read>(src: &mut BMFFBox<T>) -> Result<TryVec<TryVec<u8>>> {
 let mut iter = src.box_iter();
 let mut data = TryVec::new();
 while let Some(mut b) = iter.next_box()? {
 match b.head.name {
 BoxType::MetadataItemDataEntry => {
 data.push(read_ilst_data(&mut b)?)?;
 }
 _ => skip_box_content(&mut b)?,
 };
 check_parser_state!(b.content);
 }
 Ok(data)
}

fn read_ilst_data<T: Read>(src: &mut BMFFBox<T>) -> Result<TryVec<u8>> {
 // Skip past the padding bytes
 skip(&mut src.content, src.head.offset)?;
 let size = src.content.limit();
 read_buf(&mut src.content, size)
}

/// Skip a number of bytes that we don't care to parse.
fn skip<T: Read>(src: &mut T, bytes: u64) -> Result<()> {
 std::io::copy(&mut src.take(bytes), &mut std::io::sink())?;
 Ok(())
}

/// Read size bytes into a Vector or return error.
fn read_buf<T: Read>(src: &mut T, size: u64) -> Result<TryVec<u8>> {
 let buf = src.take(size).read_into_try_vec()?;
 if buf.len().to_u64() != size {
 return Status::ReadBufErr.into();
 }

 Ok(buf)
}

fn be_i16<T: ReadBytesExt>(src: &mut T) -> Result<i16> {
 src.read_i16::<byteorder::BigEndian>().map_err(From::from)
}

fn be_i32<T: ReadBytesExt>(src: &mut T) -> Result<i32> {
 src.read_i32::<byteorder::BigEndian>().map_err(From::from)
}

fn be_i64<T: ReadBytesExt>(src: &mut T) -> Result<i64> {
 src.read_i64::<byteorder::BigEndian>().map_err(From::from)
}

fn be_u16<T: ReadBytesExt>(src: &mut T) -> Result<u16> {
 src.read_u16::<byteorder::BigEndian>().map_err(From::from)
}

fn be_u24<T: ReadBytesExt>(src: &mut T) -> Result<u32> {
 src.read_u24::<byteorder::BigEndian>().map_err(From::from)
}

fn be_u32<T: ReadBytesExt>(src: &mut T) -> Result<u32> {
 src.read_u32::<byteorder::BigEndian>().map_err(From::from)
}

fn be_u64<T: ReadBytesExt>(src: &mut T) -> Result<u64> {
 src.read_u64::<byteorder::BigEndian>().map_err(From::from)
}

fn write_be_u32<T: WriteBytesExt>(des: &mut T, num: u32) -> Result<()> {
 des.write_u32::<byteorder::BigEndian>(num)
 .map_err(From::from)
}

#[cfg(test)]
mod media_data_box_tests {
 use super::*;

 impl DataBox {
 fn at_offset(file_offset: u64, data: std::vec::Vec<u8>) -> Self {
 DataBox {
 metadata: DataBoxMetadata::Mdat { file_offset },
 data: data.into(),
 }
 }
 }

 #[test]
 fn extent_with_length_before_mdat_returns_none() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::WithLength { offset: 0, len: 2 };

 assert!(mdat.get(&extent).is_none());
 }

 #[test]
 fn extent_to_end_before_mdat_returns_none() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::ToEnd { offset: 0 };

 assert!(mdat.get(&extent).is_none());
 }

 #[test]
 fn extent_with_length_crossing_front_mdat_boundary_returns_none() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::WithLength { offset: 99, len: 3 };

 assert!(mdat.get(&extent).is_none());
 }

 #[test]
 fn extent_with_length_which_is_subset_of_mdat() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::WithLength {
 offset: 101,
 len: 2,
 };

 assert_eq!(mdat.get(&extent), Some(&[1, 1][..]));
 }

 #[test]
 fn extent_to_end_which_is_subset_of_mdat() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::ToEnd { offset: 101 };

 assert_eq!(mdat.get(&extent), Some(&[1, 1, 1, 1][..]));
 }

 #[test]
 fn extent_with_length_which_is_all_of_mdat() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::WithLength {
 offset: 100,
 len: 5,
 };

 assert_eq!(mdat.get(&extent), Some(mdat.data.as_slice()));
 }

 #[test]
 fn extent_to_end_which_is_all_of_mdat() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::ToEnd { offset: 100 };

 assert_eq!(mdat.get(&extent), Some(mdat.data.as_slice()));
 }

 #[test]
 fn extent_with_length_crossing_back_mdat_boundary_returns_none() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::WithLength {
 offset: 103,
 len: 3,
 };

 assert!(mdat.get(&extent).is_none());
 }

 #[test]
 fn extent_with_length_after_mdat_returns_none() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::WithLength {
 offset: 200,
 len: 2,
 };

 assert!(mdat.get(&extent).is_none());
 }

 #[test]
 fn extent_to_end_after_mdat_returns_none() {
 let mdat = DataBox::at_offset(100, vec![1; 5]);
 let extent = Extent::ToEnd { offset: 200 };

 assert!(mdat.get(&extent).is_none());
 }

 #[test]
 fn extent_with_length_which_overflows_usize() {
 let mdat = DataBox::at_offset(std::u64::MAX - 1, vec![1; 5]);
 let extent = Extent::WithLength {
 offset: std::u64::MAX,
 len: std::usize::MAX,
 };

 assert!(mdat.get(&extent).is_none());
 }

 // The end of the range would overflow `usize` if it were calculated, but
 // because the range end is unbounded, we don't calculate it.
 #[test]
 fn extent_to_end_which_overflows_usize() {
 let mdat = DataBox::at_offset(std::u64::MAX - 1, vec![1; 5]);
 let extent = Extent::ToEnd {
 offset: std::u64::MAX,
 };

 assert_eq!(mdat.get(&extent), Some(&[1, 1, 1, 1][..]));
 }
}

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