/* Copyright (c) the JPEG XL Project Authors. All rights reserved. * * Use of this source code is governed by a BSD-style * license that can be found in the LICENSE file.
*/
/** @addtogroup libjxl_encoder * @{ * @file encode.h * @brief Encoding API for JPEG XL.
*/
/** * Encoder library version. * * @return the encoder library version as an integer: * MAJOR_VERSION * 1000000 + MINOR_VERSION * 1000 + PATCH_VERSION. For example, * version 1.2.3 would return 1002003.
*/
JXL_EXPORT uint32_t JxlEncoderVersion(void);
/** * Opaque structure that holds the JPEG XL encoder. * * Allocated and initialized with @ref JxlEncoderCreate(). * Cleaned up and deallocated with @ref JxlEncoderDestroy().
*/ typedefstruct JxlEncoderStruct JxlEncoder;
/** * Settings and metadata for a single image frame. This includes encoder options * for a frame such as compression quality and speed. * * Allocated and initialized with @ref JxlEncoderFrameSettingsCreate(). * Cleaned up and deallocated when the encoder is destroyed with * @ref JxlEncoderDestroy().
*/ typedefstruct JxlEncoderFrameSettingsStruct JxlEncoderFrameSettings;
/** * Return value for multiple encoder functions.
*/ typedefenum { /** Function call finished successfully, or encoding is finished and there is * nothing more to be done.
*/
JXL_ENC_SUCCESS = 0,
/** An error occurred, for example out of memory.
*/
JXL_ENC_ERROR = 1,
/** The encoder needs more output buffer to continue encoding.
*/
JXL_ENC_NEED_MORE_OUTPUT = 2,
} JxlEncoderStatus;
/** * Error conditions: * API usage errors have the 0x80 bit set to 1 * Other errors have the 0x80 bit set to 0
*/ typedefenum { /** No error
*/
JXL_ENC_ERR_OK = 0,
/** Generic encoder error due to unspecified cause
*/
JXL_ENC_ERR_GENERIC = 1,
/** Out of memory * TODO(jon): actually catch this and return this error
*/
JXL_ENC_ERR_OOM = 2,
/** JPEG bitstream reconstruction data could not be * represented (e.g. too much tail data)
*/
JXL_ENC_ERR_JBRD = 3,
/** Input is invalid (e.g. corrupt JPEG file or ICC profile)
*/
JXL_ENC_ERR_BAD_INPUT = 4,
/** The encoder doesn't (yet) support this. Either no version of libjxl * supports this, and the API is used incorrectly, or the libjxl version * should have been checked before trying to do this.
*/
JXL_ENC_ERR_NOT_SUPPORTED = 0x80,
/** The encoder API is used in an incorrect way. * In this case, a debug build of libjxl should output a specific error * message. (if not, please open an issue about it)
*/
JXL_ENC_ERR_API_USAGE = 0x81,
} JxlEncoderError;
/** * Id of encoder options for a frame. This includes options such as setting * encoding effort/speed or overriding the use of certain coding tools, for this * frame. This does not include non-frame related encoder options such as for * boxes.
*/ typedefenum { /** Sets encoder effort/speed level without affecting decoding speed. Valid * values are, from faster to slower speed: 1:lightning 2:thunder 3:falcon * 4:cheetah 5:hare 6:wombat 7:squirrel 8:kitten 9:tortoise 10:glacier. * Default: squirrel (7).
*/
JXL_ENC_FRAME_SETTING_EFFORT = 0,
/** Sets the decoding speed tier for the provided options. Minimum is 0 * (slowest to decode, best quality/density), and maximum is 4 (fastest to * decode, at the cost of some quality/density). Default is 0.
*/
JXL_ENC_FRAME_SETTING_DECODING_SPEED = 1,
/** Sets resampling option. If enabled, the image is downsampled before * compression, and upsampled to original size in the decoder. Integer option, * use -1 for the default behavior (resampling only applied for low quality), * 1 for no downsampling (1x1), 2 for 2x2 downsampling, 4 for 4x4 * downsampling, 8 for 8x8 downsampling.
*/
JXL_ENC_FRAME_SETTING_RESAMPLING = 2,
/** Similar to ::JXL_ENC_FRAME_SETTING_RESAMPLING, but for extra channels. * Integer option, use -1 for the default behavior (depends on encoder * implementation), 1 for no downsampling (1x1), 2 for 2x2 downsampling, 4 for * 4x4 downsampling, 8 for 8x8 downsampling.
*/
JXL_ENC_FRAME_SETTING_EXTRA_CHANNEL_RESAMPLING = 3,
/** Indicates the frame added with @ref JxlEncoderAddImageFrame is already * downsampled by the downsampling factor set with @ref * JXL_ENC_FRAME_SETTING_RESAMPLING. The input frame must then be given in the * downsampled resolution, not the full image resolution. The downsampled * resolution is given by ceil(xsize / resampling), ceil(ysize / resampling) * with xsize and ysize the dimensions given in the basic info, and resampling * the factor set with ::JXL_ENC_FRAME_SETTING_RESAMPLING. * Use 0 to disable, 1 to enable. Default value is 0.
*/
JXL_ENC_FRAME_SETTING_ALREADY_DOWNSAMPLED = 4,
/** Adds noise to the image emulating photographic film noise, the higher the * given number, the grainier the image will be. As an example, a value of 100 * gives low noise whereas a value of 3200 gives a lot of noise. The default * value is 0.
*/
JXL_ENC_FRAME_SETTING_PHOTON_NOISE = 5,
/** Enables adaptive noise generation. This setting is not recommended for * use, please use ::JXL_ENC_FRAME_SETTING_PHOTON_NOISE instead. Use -1 for * the default (encoder chooses), 0 to disable, 1 to enable.
*/
JXL_ENC_FRAME_SETTING_NOISE = 6,
/** Enables or disables dots generation. Use -1 for the default (encoder * chooses), 0 to disable, 1 to enable.
*/
JXL_ENC_FRAME_SETTING_DOTS = 7,
/** Enables or disables patches generation. Use -1 for the default (encoder * chooses), 0 to disable, 1 to enable.
*/
JXL_ENC_FRAME_SETTING_PATCHES = 8,
/** Edge preserving filter level, -1 to 3. Use -1 for the default (encoder * chooses), 0 to 3 to set a strength.
*/
JXL_ENC_FRAME_SETTING_EPF = 9,
/** Enables or disables the gaborish filter. Use -1 for the default (encoder * chooses), 0 to disable, 1 to enable.
*/
JXL_ENC_FRAME_SETTING_GABORISH = 10,
/** Enables modular encoding. Use -1 for default (encoder * chooses), 0 to enforce VarDCT mode (e.g. for photographic images), 1 to * enforce modular mode (e.g. for lossless images).
*/
JXL_ENC_FRAME_SETTING_MODULAR = 11,
/** Enables or disables preserving color of invisible pixels. Use -1 for the * default (1 if lossless, 0 if lossy), 0 to disable, 1 to enable.
*/
JXL_ENC_FRAME_SETTING_KEEP_INVISIBLE = 12,
/** Determines the order in which 256x256 regions are stored in the codestream * for progressive rendering. Use -1 for the encoder * default, 0 for scanline order, 1 for center-first order.
*/
JXL_ENC_FRAME_SETTING_GROUP_ORDER = 13,
/** Determines the horizontal position of center for the center-first group * order. Use -1 to automatically use the middle of the image, 0..xsize to * specifically set it.
*/
JXL_ENC_FRAME_SETTING_GROUP_ORDER_CENTER_X = 14,
/** Determines the center for the center-first group order. Use -1 to * automatically use the middle of the image, 0..ysize to specifically set it.
*/
JXL_ENC_FRAME_SETTING_GROUP_ORDER_CENTER_Y = 15,
/** Enables or disables progressive encoding for modular mode. Use -1 for the * encoder default, 0 to disable, 1 to enable.
*/
JXL_ENC_FRAME_SETTING_RESPONSIVE = 16,
/** Set the progressive mode for the AC coefficients of VarDCT, using spectral * progression from the DCT coefficients. Use -1 for the encoder default, 0 to * disable, 1 to enable.
*/
JXL_ENC_FRAME_SETTING_PROGRESSIVE_AC = 17,
/** Set the progressive mode for the AC coefficients of VarDCT, using * quantization of the least significant bits. Use -1 for the encoder default, * 0 to disable, 1 to enable.
*/
JXL_ENC_FRAME_SETTING_QPROGRESSIVE_AC = 18,
/** Set the progressive mode using lower-resolution DC images for VarDCT. Use * -1 for the encoder default, 0 to disable, 1 to have an extra 64x64 lower * resolution pass, 2 to have a 512x512 and 64x64 lower resolution pass.
*/
JXL_ENC_FRAME_SETTING_PROGRESSIVE_DC = 19,
/** Use Global channel palette if the amount of colors is smaller than this * percentage of range. Use 0-100 to set an explicit percentage, -1 to use the * encoder default. Used for modular encoding.
*/
JXL_ENC_FRAME_SETTING_CHANNEL_COLORS_GLOBAL_PERCENT = 20,
/** Use Local (per-group) channel palette if the amount of colors is smaller * than this percentage of range. Use 0-100 to set an explicit percentage, -1 * to use the encoder default. Used for modular encoding.
*/
JXL_ENC_FRAME_SETTING_CHANNEL_COLORS_GROUP_PERCENT = 21,
/** Use color palette if amount of colors is smaller than or equal to this * amount, or -1 to use the encoder default. Used for modular encoding.
*/
JXL_ENC_FRAME_SETTING_PALETTE_COLORS = 22,
/** Enables or disables delta palette. Use -1 for the default (encoder * chooses), 0 to disable, 1 to enable. Used in modular mode.
*/
JXL_ENC_FRAME_SETTING_LOSSY_PALETTE = 23,
/** Color transform for internal encoding: -1 = default, 0=XYB, 1=none (RGB), * 2=YCbCr. The XYB setting performs the forward XYB transform. None and * YCbCr both perform no transform, but YCbCr is used to indicate that the * encoded data losslessly represents YCbCr values.
*/
JXL_ENC_FRAME_SETTING_COLOR_TRANSFORM = 24,
/** Reversible color transform for modular encoding: -1=default, 0-41=RCT * index, e.g. index 0 = none, index 6 = YCoCg. * If this option is set to a non-default value, the RCT will be globally * applied to the whole frame. * The default behavior is to try several RCTs locally per modular group, * depending on the speed and distance setting.
*/
JXL_ENC_FRAME_SETTING_MODULAR_COLOR_SPACE = 25,
/** Group size for modular encoding: -1=default, 0=128, 1=256, 2=512, 3=1024.
*/
JXL_ENC_FRAME_SETTING_MODULAR_GROUP_SIZE = 26,
/** Fraction of pixels used to learn MA trees as a percentage. -1 = default, * 0 = no MA and fast decode, 50 = default value, 100 = all, values above * 100 are also permitted. Higher values use more encoder memory.
*/
JXL_ENC_FRAME_SETTING_MODULAR_MA_TREE_LEARNING_PERCENT = 28,
/** Number of extra (previous-channel) MA tree properties to use. -1 = * default, 0-11 = valid values. Recommended values are in the range 0 to 3, * or 0 to amount of channels minus 1 (including all extra channels, and * excluding color channels when using VarDCT mode). Higher value gives slower * encoding and slower decoding.
*/
JXL_ENC_FRAME_SETTING_MODULAR_NB_PREV_CHANNELS = 29,
/** Prepare the frame for indexing in the frame index box. * 0 = ignore this frame (same as not setting a value), * 1 = index this frame within the Frame Index Box. * If any frames are indexed, the first frame needs to * be indexed, too. If the first frame is not indexed, and * a later frame is attempted to be indexed, ::JXL_ENC_ERROR will occur. * If non-keyframes, i.e., frames with cropping, blending or patches are * attempted to be indexed, ::JXL_ENC_ERROR will occur.
*/
JXL_ENC_FRAME_INDEX_BOX = 31,
/** Sets brotli encode effort for use in JPEG recompression and * compressed metadata boxes (brob). Can be -1 (default) or 0 (fastest) to 11 * (slowest). Default is based on the general encode effort in case of JPEG * recompression, and 4 for brob boxes.
*/
JXL_ENC_FRAME_SETTING_BROTLI_EFFORT = 32,
/** Enables or disables brotli compression of metadata boxes derived from * a JPEG frame when using @ref JxlEncoderAddJPEGFrame. This has no effect on * boxes added using @ref JxlEncoderAddBox. -1 = default, 0 = disable * compression, 1 = enable compression.
*/
JXL_ENC_FRAME_SETTING_JPEG_COMPRESS_BOXES = 33,
/** Control what kind of buffering is used, when using chunked image frames. * -1 = default (let the encoder decide) * 0 = buffers everything, basically the same as non-streamed code path (mainly for testing) * 1 = buffers everything for images that are smaller than 2048 x 2048, and * uses streaming input and output for larger images * 2 = uses streaming input and output for all images that are larger than * one group, i.e. 256 x 256 pixels by default * 3 = currently same as 2 * * When using streaming input and output the encoder minimizes memory usage at * the cost of compression density. Also note that images produced with * streaming mode might not be progressively decodeable.
*/
JXL_ENC_FRAME_SETTING_BUFFERING = 34,
/** Keep or discard Exif metadata boxes derived from a JPEG frame when using * @ref JxlEncoderAddJPEGFrame. This has no effect on boxes added using * @ref JxlEncoderAddBox. When @ref JxlEncoderStoreJPEGMetadata is set to 1, * this option cannot be set to 0. Even when Exif metadata is discarded, the * orientation will still be applied. 0 = discard Exif metadata, 1 = keep Exif * metadata (default).
*/
JXL_ENC_FRAME_SETTING_JPEG_KEEP_EXIF = 35,
/** Keep or discard XMP metadata boxes derived from a JPEG frame when using * @ref JxlEncoderAddJPEGFrame. This has no effect on boxes added using * @ref JxlEncoderAddBox. When @ref JxlEncoderStoreJPEGMetadata is set to 1, * this option cannot be set to 0. 0 = discard XMP metadata, 1 = keep XMP * metadata (default).
*/
JXL_ENC_FRAME_SETTING_JPEG_KEEP_XMP = 36,
/** Keep or discard JUMBF metadata boxes derived from a JPEG frame when using * @ref JxlEncoderAddJPEGFrame. This has no effect on boxes added using * @ref JxlEncoderAddBox. 0 = discard JUMBF metadata, 1 = keep JUMBF metadata * (default).
*/
JXL_ENC_FRAME_SETTING_JPEG_KEEP_JUMBF = 37,
/** If this mode is disabled, the encoder will not make any image quality * decisions that are computed based on the full image, but stored only once * (e.g. the X quant multiplier in the frame header). Used mainly for testing * equivalence of streaming and non-streaming code. * 0 = disabled, 1 = enabled (default)
*/
JXL_ENC_FRAME_SETTING_USE_FULL_IMAGE_HEURISTICS = 38,
/** Enum value not to be used as an option. This value is added to force the * C compiler to have the enum to take a known size.
*/
JXL_ENC_FRAME_SETTING_FILL_ENUM = 65535,
} JxlEncoderFrameSettingId;
/** * Creates an instance of @ref JxlEncoder and initializes it. * * @p memory_manager will be used for all the library dynamic allocations made * from this instance. The parameter may be NULL, in which case the default * allocator will be used. See jpegxl/memory_manager.h for details. * * @param memory_manager custom allocator function. It may be NULL. The memory * manager will be copied internally. * @return @c NULL if the instance can not be allocated or initialized * @return pointer to initialized @ref JxlEncoder otherwise
*/
JXL_EXPORT JxlEncoder* JxlEncoderCreate(const JxlMemoryManager* memory_manager);
/** * Re-initializes a @ref JxlEncoder instance, so it can be re-used for encoding * another image. All state and settings are reset as if the object was * newly created with @ref JxlEncoderCreate, but the memory manager is kept. * * @param enc instance to be re-initialized.
*/
JXL_EXPORT void JxlEncoderReset(JxlEncoder* enc);
/** * Deinitializes and frees a @ref JxlEncoder instance. * * @param enc instance to be cleaned up and deallocated.
*/
JXL_EXPORT void JxlEncoderDestroy(JxlEncoder* enc);
/** * Sets the color management system (CMS) that will be used for color conversion * (if applicable) during encoding. May only be set before starting encoding. If * left unset, the default CMS implementation will be used. * * @param enc encoder object. * @param cms structure representing a CMS implementation. See @ref * JxlCmsInterface for more details.
*/
JXL_EXPORT void JxlEncoderSetCms(JxlEncoder* enc, JxlCmsInterface cms);
/** * Set the parallel runner for multithreading. May only be set before starting * encoding. * * @param enc encoder object. * @param parallel_runner function pointer to runner for multithreading. It may * be NULL to use the default, single-threaded, runner. A multithreaded * runner should be set to reach fast performance. * @param parallel_runner_opaque opaque pointer for parallel_runner. * @return ::JXL_ENC_SUCCESS if the runner was set, ::JXL_ENC_ERROR * otherwise (the previous runner remains set).
*/
JXL_EXPORT JxlEncoderStatus
JxlEncoderSetParallelRunner(JxlEncoder* enc, JxlParallelRunner parallel_runner, void* parallel_runner_opaque);
/** * Get the (last) error code in case ::JXL_ENC_ERROR was returned. * * @param enc encoder object. * @return the @ref JxlEncoderError that caused the (last) ::JXL_ENC_ERROR to * be returned.
*/
JXL_EXPORT JxlEncoderError JxlEncoderGetError(JxlEncoder* enc);
/** * Encodes a JPEG XL file using the available bytes. @p *avail_out indicates how * many output bytes are available, and @p *next_out points to the input bytes. * *avail_out will be decremented by the amount of bytes that have been * processed by the encoder and *next_out will be incremented by the same * amount, so *next_out will now point at the amount of *avail_out unprocessed * bytes. * * The returned status indicates whether the encoder needs more output bytes. * When the return value is not ::JXL_ENC_ERROR or ::JXL_ENC_SUCCESS, the * encoding requires more @ref JxlEncoderProcessOutput calls to continue. * * The caller must guarantee that *avail_out >= 32 when calling * @ref JxlEncoderProcessOutput; otherwise, ::JXL_ENC_NEED_MORE_OUTPUT will * be returned. It is guaranteed that, if *avail_out >= 32, at least one byte of * output will be written. * * This encodes the frames and/or boxes added so far. If the last frame or last * box has been added, @ref JxlEncoderCloseInput, @ref JxlEncoderCloseFrames * and/or @ref JxlEncoderCloseBoxes must be called before the next * @ref JxlEncoderProcessOutput call, or the codestream won't be encoded * correctly. * * @param enc encoder object. * @param next_out pointer to next bytes to write to. * @param avail_out amount of bytes available starting from *next_out. * @return ::JXL_ENC_SUCCESS when encoding finished and all events handled. * @return ::JXL_ENC_ERROR when encoding failed, e.g. invalid input. * @return ::JXL_ENC_NEED_MORE_OUTPUT more output buffer is necessary.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderProcessOutput(JxlEncoder* enc,
uint8_t** next_out,
size_t* avail_out);
/** * Sets the frame information for this frame to the encoder. This includes * animation information such as frame duration to store in the frame header. * The frame header fields represent the frame as passed to the encoder, but not * necessarily the exact values as they will be encoded file format: the encoder * could change crop and blending options of a frame for more efficient encoding * or introduce additional internal frames. Animation duration and time code * information is not altered since those are immutable metadata of the frame. * * It is not required to use this function, however if have_animation is set * to true in the basic info, then this function should be used to set the * time duration of this individual frame. By default individual frames have a * time duration of 0, making them form a composite still. See @ref * JxlFrameHeader for more information. * * This information is stored in the @ref JxlEncoderFrameSettings and so is used * for any frame encoded with these @ref JxlEncoderFrameSettings. It is ok to * change between @ref JxlEncoderAddImageFrame calls, each added image frame * will have the frame header that was set in the options at the time of calling * @ref JxlEncoderAddImageFrame. * * The is_last and name_length fields of the @ref JxlFrameHeader are ignored, * use * @ref JxlEncoderCloseFrames to indicate last frame, and @ref * JxlEncoderSetFrameName to indicate the name and its length instead. * Calling this function will clear any name that was previously set with @ref * JxlEncoderSetFrameName. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param frame_header frame header data to set. Object owned by the caller and * does not need to be kept in memory, its information is copied internally. * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
*/
JXL_EXPORT JxlEncoderStatus
JxlEncoderSetFrameHeader(JxlEncoderFrameSettings* frame_settings, const JxlFrameHeader* frame_header);
/** * Sets blend info of an extra channel. The blend info of extra channels is set * separately from that of the color channels, the color channels are set with * @ref JxlEncoderSetFrameHeader. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param index index of the extra channel to use. * @param blend_info blend info to set for the extra channel * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelBlendInfo(
JxlEncoderFrameSettings* frame_settings, size_t index, const JxlBlendInfo* blend_info);
/** * Sets the name of the animation frame. This function is optional, frames are * not required to have a name. This setting is a part of the frame header, and * the same principles as for @ref JxlEncoderSetFrameHeader apply. The * name_length field of @ref JxlFrameHeader is ignored by the encoder, this * function determines the name length instead as the length in bytes of the C * string. * * The maximum possible name length is 1071 bytes (excluding terminating null * character). * * Calling @ref JxlEncoderSetFrameHeader clears any name that was * previously set. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param frame_name name of the next frame to be encoded, as a UTF-8 encoded C * string (zero terminated). Owned by the caller, and copied internally. * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetFrameName(
JxlEncoderFrameSettings* frame_settings, constchar* frame_name);
/** * Sets the bit depth of the input buffer. * * For float pixel formats, only the default @ref JXL_BIT_DEPTH_FROM_PIXEL_FORMAT * setting is allowed, while for unsigned pixel formats, * ::JXL_BIT_DEPTH_FROM_CODESTREAM setting is also allowed. See the comment on * @ref JxlEncoderAddImageFrame for the effects of the bit depth setting.
* @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param bit_depth the bit depth setting of the pixel input * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetFrameBitDepth(
JxlEncoderFrameSettings* frame_settings, const JxlBitDepth* bit_depth);
/** * Sets the buffer to read JPEG encoded bytes from for the next frame to encode. * * If @ref JxlEncoderSetBasicInfo has not yet been called, calling * @ref JxlEncoderAddJPEGFrame will implicitly call it with the parameters of * the added JPEG frame. * * If @ref JxlEncoderSetColorEncoding or @ref JxlEncoderSetICCProfile has not * yet been called, calling @ref JxlEncoderAddJPEGFrame will implicitly call it * with the parameters of the added JPEG frame. * * If the encoder is set to store JPEG reconstruction metadata using @ref * JxlEncoderStoreJPEGMetadata and a single JPEG frame is added, it will be * possible to losslessly reconstruct the JPEG codestream. * * If this is the last frame, @ref JxlEncoderCloseInput or @ref * JxlEncoderCloseFrames must be called before the next * @ref JxlEncoderProcessOutput call. * * Note, this can only be used to add JPEG frames for lossless compression. To * encode with lossy compression, the JPEG must be decoded manually and a pixel * buffer added using JxlEncoderAddImageFrame. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param buffer bytes to read JPEG from. Owned by the caller and its contents * are copied internally. * @param size size of buffer in bytes. * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
*/
JXL_EXPORT JxlEncoderStatus
JxlEncoderAddJPEGFrame(const JxlEncoderFrameSettings* frame_settings, const uint8_t* buffer, size_t size);
/** * Sets the buffer to read pixels from for the next image to encode. Must call * @ref JxlEncoderSetBasicInfo before @ref JxlEncoderAddImageFrame. * * Currently only some data types for pixel formats are supported: * - ::JXL_TYPE_UINT8, with range 0..255 * - ::JXL_TYPE_UINT16, with range 0..65535 * - ::JXL_TYPE_FLOAT16, with nominal range 0..1 * - ::JXL_TYPE_FLOAT, with nominal range 0..1 * * Note: the sample data type in pixel_format is allowed to be different from * what is described in the @ref JxlBasicInfo. The type in pixel_format, * together with an optional @ref JxlBitDepth parameter set by @ref * JxlEncoderSetFrameBitDepth describes the format of the uncompressed pixel * buffer. The bits_per_sample and exponent_bits_per_sample in the @ref * JxlBasicInfo describes what will actually be encoded in the JPEG XL * codestream. For example, to encode a 12-bit image, you would set * bits_per_sample to 12, while the input frame buffer can be in the following * formats: * - if pixel format is in ::JXL_TYPE_UINT16 with default bit depth setting * (i.e. ::JXL_BIT_DEPTH_FROM_PIXEL_FORMAT), input sample values are * rescaled to 16-bit, i.e. multiplied by 65535/4095; * - if pixel format is in ::JXL_TYPE_UINT16 with @ref * JXL_BIT_DEPTH_FROM_CODESTREAM bit depth setting, input sample values are * provided unscaled; * - if pixel format is in ::JXL_TYPE_FLOAT, input sample values are * rescaled to 0..1, i.e. multiplied by 1.f/4095.f. While it is allowed, it is * obviously not recommended to use a pixel_format with lower precision than * what is specified in the @ref JxlBasicInfo. * * We support interleaved channels as described by the @ref JxlPixelFormat * "JxlPixelFormat": * - single-channel data, e.g. grayscale * - single-channel + alpha * - trichromatic, e.g. RGB * - trichromatic + alpha * * Extra channels not handled here need to be set by @ref * JxlEncoderSetExtraChannelBuffer. * If the image has alpha, and alpha is not passed here, it will implicitly be * set to all-opaque (an alpha value of 1.0 everywhere). * * The pixels are assumed to be encoded in the original profile that is set with * @ref JxlEncoderSetColorEncoding or @ref JxlEncoderSetICCProfile. If none of * these functions were used, the pixels are assumed to be nonlinear sRGB for * integer data types (::JXL_TYPE_UINT8, ::JXL_TYPE_UINT16), and linear * sRGB for floating point data types (::JXL_TYPE_FLOAT16, @ref * JXL_TYPE_FLOAT). * * Sample values in floating-point pixel formats are allowed to be outside the * nominal range, e.g. to represent out-of-sRGB-gamut colors in the * uses_original_profile=false case. They are however not allowed to be NaN or * +-infinity. * * If this is the last frame, @ref JxlEncoderCloseInput or @ref * JxlEncoderCloseFrames must be called before the next * @ref JxlEncoderProcessOutput call. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param pixel_format format for pixels. Object owned by the caller and its * contents are copied internally. * @param buffer buffer type to input the pixel data from. Owned by the caller * and its contents are copied internally. * @param size size of buffer in bytes. This size should match what is implied * by the frame dimensions and the pixel format. * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderAddImageFrame( const JxlEncoderFrameSettings* frame_settings, const JxlPixelFormat* pixel_format, constvoid* buffer, size_t size);
/** * The @ref JxlEncoderOutputProcessor structure provides an interface for the * encoder's output processing. Users of the library, who want to do streaming * encoding, should implement the required callbacks for buffering, writing, * seeking (if supported), and setting a finalized position during the encoding * process. * * At a high level, the processor can be in one of two states: * - With an active buffer: This indicates that a buffer has been acquired using * `get_buffer` and encoded data can be written to it. * - Without an active buffer: In this state, no data can be written. A new * buffer must be acquired after releasing any previously active buffer. * * The library will not acquire more than one buffer at a given time. * * The state of the processor includes `position` and `finalized position`, * which have the following meaning. * * - position: Represents the current position, in bytes, within the output * stream where the encoded data will be written next. This position moves * forward with each `release_buffer` call as data is written, and can also be * adjusted through the optional seek callback, if provided. At this position * the next write will occur. * * - finalized position: A position in the output stream that ensures all bytes * before this point are finalized and won't be changed by later writes. * * All fields but `seek` are required, `seek` is optional and can be NULL.
*/ struct JxlEncoderOutputProcessor { /** * Required. * An opaque pointer that the client can use to store custom data. * This data will be passed to the associated callback functions.
*/ void* opaque;
/** * Required. * Acquires a buffer at the current position into which the library will write * the output data. * * If the `size` argument points to 0 and the returned value is NULL, this * will be interpreted as asking the output writing to stop. In such a case, * the library will return an error. The client is expected to set the size of * the returned buffer based on the suggested `size` when this function is * called. * * @param opaque user supplied parameters to the callback * @param size points to a suggested buffer size when called; must be set to * the size of the returned buffer once the function returns. * @return a pointer to the acquired buffer or NULL to indicate a stop * condition.
*/ void* (*get_buffer)(void* opaque, size_t* size);
/** * Required. * Notifies the user of library that the current buffer's data has been * written and can be released. This function should advance the current * position of the buffer by `written_bytes` number of bytes. * * @param opaque user supplied parameters to the callback * @param written_bytes the number of bytes written to the buffer.
*/ void (*release_buffer)(void* opaque, size_t written_bytes);
/** * Optional, can be NULL * Seeks to a specific position in the output. This function is optional and * can be set to NULL if the output doesn't support seeking. Can only be done * when there is no buffer. Cannot be used to seek before the finalized * position. * * @param opaque user supplied parameters to the callback * @param position the position to seek to, in bytes.
*/ void (*seek)(void* opaque, uint64_t position);
/** * Required. * Sets a finalized position on the output data, at a specific position. * Seeking will never request a position before the finalized position. * * Will only be called if there is no active buffer. * * @param opaque user supplied parameters to the callback * @param finalized_position the position, in bytes, where the finalized * position should be set.
*/ void (*set_finalized_position)(void* opaque, uint64_t finalized_position);
};
/** * Sets the output processor for the encoder. This processor determines how the * encoder will handle buffering, writing, seeking (if supported), and * setting a finalized position during the encoding process. * * This should not be used when using @ref JxlEncoderProcessOutput. * * @param enc encoder object. * @param output_processor the struct containing the callbacks for managing * output. * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetOutputProcessor(
JxlEncoder* enc, struct JxlEncoderOutputProcessor output_processor);
/** * Flushes any buffered input in the encoder, ensuring that all available input * data has been processed and written to the output. * * This function can only be used after @ref JxlEncoderSetOutputProcessor. * Before making the last call to @ref JxlEncoderFlushInput, users should call * @ref JxlEncoderCloseInput to signal the end of input data. * * This should not be used when using @ref JxlEncoderProcessOutput. * * @param enc encoder object. * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderFlushInput(JxlEncoder* enc);
/** * This struct provides callback functions to pass pixel data in a streaming * manner instead of requiring the entire frame data in memory at once.
*/ struct JxlChunkedFrameInputSource { /** * A pointer to any user-defined data or state. This can be used to pass * information to the callback functions.
*/ void* opaque;
/** * Get the pixel format that color channel data will be provided in. * When called, `pixel_format` points to a suggested pixel format; if * color channel data can be given in this pixel format, processing might * be more efficient. * * This function will be called exactly once, before any call to * get_color_channel_at. * * @param opaque user supplied parameters to the callback * @param pixel_format format for pixels
*/ void (*get_color_channels_pixel_format)(void* opaque,
JxlPixelFormat* pixel_format);
/** * Callback to retrieve a rectangle of color channel data at a specific * location. It is guaranteed that xpos and ypos are multiples of 8. xsize, * ysize will be multiples of 8, unless the resulting rectangle would be out * of image bounds. Moreover, xsize and ysize will be at most 2048. The * returned data will be assumed to be in the format returned by the * (preceding) call to get_color_channels_pixel_format, except the `align` * parameter of the pixel format will be ignored. Instead, the `i`-th row will * be assumed to start at position `return_value + i * *row_offset`, with the * value of `*row_offset` decided by the callee. * * Note that multiple calls to `get_color_channel_data_at` may happen before a * call to `release_buffer`. * * @param opaque user supplied parameters to the callback * @param xpos horizontal position for the data. * @param ypos vertical position for the data. * @param xsize horizontal size of the requested rectangle of data. * @param ysize vertical size of the requested rectangle of data. * @param row_offset pointer to a the byte offset between consecutive rows of * the retrieved pixel data. * @return pointer to the retrieved pixel data.
*/ constvoid* (*get_color_channel_data_at)(void* opaque, size_t xpos,
size_t ypos, size_t xsize,
size_t ysize, size_t* row_offset);
/** * Get the pixel format that extra channel data will be provided in. * When called, `pixel_format` points to a suggested pixel format; if * extra channel data can be given in this pixel format, processing might * be more efficient. * * This function will be called exactly once per index, before any call to * get_extra_channel_data_at with that given index. * * @param opaque user supplied parameters to the callback * @param ec_index zero-indexed index of the extra channel * @param pixel_format format for extra channel data
*/ void (*get_extra_channel_pixel_format)(void* opaque, size_t ec_index,
JxlPixelFormat* pixel_format);
/** * Callback to retrieve a rectangle of extra channel `ec_index` data at a * specific location. It is guaranteed that xpos and ypos are multiples of * 8. xsize, ysize will be multiples of 8, unless the resulting rectangle * would be out of image bounds. Moreover, xsize and ysize will be at most * 2048. The returned data will be assumed to be in the format returned by the * (preceding) call to get_extra_channels_pixel_format_at with the * corresponding extra channel index `ec_index`, except the `align` parameter * of the pixel format will be ignored. Instead, the `i`-th row will be * assumed to start at position `return_value + i * *row_offset`, with the * value of `*row_offset` decided by the callee. * * Note that multiple calls to `get_extra_channel_data_at` may happen before a * call to `release_buffer`. * * @param opaque user supplied parameters to the callback * @param xpos horizontal position for the data. * @param ypos vertical position for the data. * @param xsize horizontal size of the requested rectangle of data. * @param ysize vertical size of the requested rectangle of data. * @param row_offset pointer to a the byte offset between consecutive rows of * the retrieved pixel data. * @return pointer to the retrieved pixel data.
*/ constvoid* (*get_extra_channel_data_at)(void* opaque, size_t ec_index,
size_t xpos, size_t ypos,
size_t xsize, size_t ysize,
size_t* row_offset);
/** * Releases the buffer `buf` (obtained through a call to * `get_color_channel_data_at` or `get_extra_channel_data_at`). This function * will be called exactly once per call to `get_color_channel_data_at` or * `get_extra_channel_data_at`. * * @param opaque user supplied parameters to the callback * @param buf pointer returned by `get_color_channel_data_at` or * `get_extra_channel_data_at`
*/ void (*release_buffer)(void* opaque, constvoid* buf);
};
/** * @brief Adds a frame to the encoder using a chunked input source. * * This function gives a way to encode a frame by providing pixel data in a * chunked or streaming manner, which can be especially useful when dealing with * large images that may not fit entirely in memory or when trying to optimize * memory usage. The input data is provided through callbacks defined in the * @ref JxlChunkedFrameInputSource struct. Once the frame data has been * completely retrieved, this function will flush the input and close it if it * is the last frame. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param is_last_frame indicates if this is the last frame. * @param chunked_frame_input struct providing callback methods for retrieving * pixel data in chunks. * * @return Returns a status indicating the success or failure of adding the * frame.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderAddChunkedFrame( const JxlEncoderFrameSettings* frame_settings, JXL_BOOL is_last_frame, struct JxlChunkedFrameInputSource chunked_frame_input);
/** * Sets the buffer to read pixels from for an extra channel at a given index. * The index must be smaller than the num_extra_channels in the associated * @ref JxlBasicInfo. Must call @ref JxlEncoderSetExtraChannelInfo before @ref * JxlEncoderSetExtraChannelBuffer. * * TODO(firsching): mention what data types in pixel formats are supported. * * It is required to call this function for every extra channel, except for the * alpha channel if that was already set through @ref JxlEncoderAddImageFrame. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param pixel_format format for pixels. Object owned by the caller and its * contents are copied internally. The num_channels value is ignored, since the * number of channels for an extra channel is always assumed to be one. * @param buffer buffer type to input the pixel data from. Owned by the caller * and its contents are copied internally. * @param size size of buffer in bytes. This size should match what is implied * by the frame dimensions and the pixel format. * @param index index of the extra channel to use. * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelBuffer( const JxlEncoderFrameSettings* frame_settings, const JxlPixelFormat* pixel_format, constvoid* buffer, size_t size,
uint32_t index);
/** Adds a metadata box to the file format. @ref JxlEncoderProcessOutput must be * used to effectively write the box to the output. @ref JxlEncoderUseBoxes must * be enabled before using this function. * * Boxes allow inserting application-specific data and metadata (Exif, XML/XMP, * JUMBF and user defined boxes). * * The box format follows ISO BMFF and shares features and box types with other * image and video formats, including the Exif, XML and JUMBF boxes. The box * format for JPEG XL is specified in ISO/IEC 18181-2. * * Boxes in general don't contain other boxes inside, except a JUMBF superbox. * Boxes follow each other sequentially and are byte-aligned. If the container * format is used, the JXL stream consists of concatenated boxes. * It is also possible to use a direct codestream without boxes, but in that * case metadata cannot be added. * * Each box generally has the following byte structure in the file: * - 4 bytes: box size including box header (Big endian. If set to 0, an * 8-byte 64-bit size follows instead). * - 4 bytes: type, e.g. "JXL " for the signature box, "jxlc" for a codestream * box. * - N bytes: box contents. * * Only the box contents are provided to the contents argument of this function, * the encoder encodes the size header itself. Most boxes are written * automatically by the encoder as needed ("JXL ", "ftyp", "jxll", "jxlc", * "jxlp", "jxli", "jbrd"), and this function only needs to be called to add * optional metadata when encoding from pixels (using @ref * JxlEncoderAddImageFrame). When recompressing JPEG files (using @ref * JxlEncoderAddJPEGFrame), if the input JPEG contains EXIF, XMP or JUMBF * metadata, the corresponding boxes are already added automatically. * * Box types are given by 4 characters. The following boxes can be added with * this function: * - "Exif": a box with EXIF metadata, can be added by libjxl users, or is * automatically added when needed for JPEG reconstruction. The contents of * this box must be prepended by a 4-byte tiff header offset, which may * be 4 zero bytes in case the tiff header follows immediately. * The EXIF metadata must be in sync with what is encoded in the JPEG XL * codestream, specifically the image orientation. While this is not * recommended in practice, in case of conflicting metadata, the JPEG XL * codestream takes precedence. * - "xml ": a box with XML data, in particular XMP metadata, can be added by * libjxl users, or is automatically added when needed for JPEG reconstruction * - "jumb": a JUMBF superbox, which can contain boxes with different types of * metadata inside. This box type can be added by the encoder transparently, * and other libraries to create and handle JUMBF content exist. * - Application-specific boxes. Their typename should not begin with "jxl" or * "JXL" or conflict with other existing typenames, and they should be * registered with MP4RA (mp4ra.org). * * These boxes can be stored uncompressed or Brotli-compressed (using a "brob" * box), depending on the compress_box parameter. * * @param enc encoder object. * @param type the box type, e.g. "Exif" for EXIF metadata, "xml " for XMP or * IPTC metadata, "jumb" for JUMBF metadata. * @param contents the full contents of the box, for example EXIF * data. ISO BMFF box header must not be included, only the contents. Owned by * the caller and its contents are copied internally. * @param size size of the box contents. * @param compress_box Whether to compress this box as a "brob" box. Requires * Brotli support. * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error, such as * when using this function without @ref JxlEncoderUseContainer, or adding a box * type that would result in an invalid file format.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderAddBox(JxlEncoder* enc, const JxlBoxType type, const uint8_t* contents,
size_t size,
JXL_BOOL compress_box);
/** * Indicates the intention to add metadata boxes. This allows @ref * JxlEncoderAddBox to be used. When using this function, then it is required * to use @ref JxlEncoderCloseBoxes at the end. * * By default the encoder assumes no metadata boxes will be added. * * This setting can only be set at the beginning, before encoding starts. * * @param enc encoder object.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderUseBoxes(JxlEncoder* enc);
/** * Declares that no further boxes will be added with @ref JxlEncoderAddBox. * This function must be called after the last box is added so the encoder knows * the stream will be finished. It is not necessary to use this function if * @ref JxlEncoderUseBoxes is not used. Further frames may still be added. * * Must be called between @ref JxlEncoderAddBox of the last box * and the next call to @ref JxlEncoderProcessOutput, or @ref * JxlEncoderProcessOutput won't output the last box correctly. * * NOTE: if you don't need to close frames and boxes at separate times, you can * use @ref JxlEncoderCloseInput instead to close both at once. * * @param enc encoder object.
*/
JXL_EXPORT void JxlEncoderCloseBoxes(JxlEncoder* enc);
/** * Declares that no frames will be added and @ref JxlEncoderAddImageFrame and * @ref JxlEncoderAddJPEGFrame won't be called anymore. Further metadata boxes * may still be added. This function or @ref JxlEncoderCloseInput must be called * after adding the last frame and the next call to * @ref JxlEncoderProcessOutput, or the frame won't be properly marked as last. * * NOTE: if you don't need to close frames and boxes at separate times, you can * use @ref JxlEncoderCloseInput instead to close both at once. * * @param enc encoder object.
*/
JXL_EXPORT void JxlEncoderCloseFrames(JxlEncoder* enc);
/** * Closes any input to the encoder, equivalent to calling @ref * JxlEncoderCloseFrames as well as calling @ref JxlEncoderCloseBoxes if needed. * No further input of any kind may be given to the encoder, but further @ref * JxlEncoderProcessOutput calls should be done to create the final output. * * The requirements of both @ref JxlEncoderCloseFrames and @ref * JxlEncoderCloseBoxes apply to this function. Either this function or the * other two must be called after the final frame and/or box, and the next * @ref JxlEncoderProcessOutput call, or the codestream won't be encoded * correctly. * * @param enc encoder object.
*/
JXL_EXPORT void JxlEncoderCloseInput(JxlEncoder* enc);
/** * Sets the original color encoding of the image encoded by this encoder. This * is an alternative to @ref JxlEncoderSetICCProfile and only one of these two * must be used. This one sets the color encoding as a @ref JxlColorEncoding, * while the other sets it as ICC binary data. Must be called after @ref * JxlEncoderSetBasicInfo. * * @param enc encoder object. * @param color color encoding. Object owned by the caller and its contents are * copied internally. * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref * JXL_ENC_ERROR otherwise
*/
JXL_EXPORT JxlEncoderStatus
JxlEncoderSetColorEncoding(JxlEncoder* enc, const JxlColorEncoding* color);
/** * Sets the original color encoding of the image encoded by this encoder as an * ICC color profile. This is an alternative to @ref JxlEncoderSetColorEncoding * and only one of these two must be used. This one sets the color encoding as * ICC binary data, while the other defines it as a @ref JxlColorEncoding. Must * be called after @ref JxlEncoderSetBasicInfo. * * @param enc encoder object. * @param icc_profile bytes of the original ICC profile * @param size size of the icc_profile buffer in bytes * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref * JXL_ENC_ERROR otherwise
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetICCProfile(JxlEncoder* enc, const uint8_t* icc_profile,
size_t size);
/** * Initializes a @ref JxlBasicInfo struct to default values. * For forwards-compatibility, this function has to be called before values * are assigned to the struct fields. * The default values correspond to an 8-bit RGB image, no alpha or any * other extra channels. * * @param info global image metadata. Object owned by the caller.
*/
JXL_EXPORT void JxlEncoderInitBasicInfo(JxlBasicInfo* info);
/** * Initializes a @ref JxlFrameHeader struct to default values. * For forwards-compatibility, this function has to be called before values * are assigned to the struct fields. * The default values correspond to a frame with no animation duration and the * 'replace' blend mode. After using this function, For animation duration must * be set, for composite still blend settings must be set. * * @param frame_header frame metadata. Object owned by the caller.
*/
JXL_EXPORT void JxlEncoderInitFrameHeader(JxlFrameHeader* frame_header);
/** * Initializes a @ref JxlBlendInfo struct to default values. * For forwards-compatibility, this function has to be called before values * are assigned to the struct fields. * * @param blend_info blending info. Object owned by the caller.
*/
JXL_EXPORT void JxlEncoderInitBlendInfo(JxlBlendInfo* blend_info);
/** * Sets the global metadata of the image encoded by this encoder. * * If the @ref JxlBasicInfo contains information of extra channels beyond an * alpha channel, then @ref JxlEncoderSetExtraChannelInfo must be called between * @ref JxlEncoderSetBasicInfo and @ref JxlEncoderAddImageFrame. In order to * indicate extra channels, the value of `info.num_extra_channels` should be set * to the number of extra channels, also counting the alpha channel if present. * * @param enc encoder object. * @param info global image metadata. Object owned by the caller and its * contents are copied internally. * @return ::JXL_ENC_SUCCESS if the operation was successful, * ::JXL_ENC_ERROR otherwise
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetBasicInfo(JxlEncoder* enc, const JxlBasicInfo* info);
/** * Sets the upsampling method the decoder will use in case there are frames * with ::JXL_ENC_FRAME_SETTING_RESAMPLING set. This is useful in combination * with the ::JXL_ENC_FRAME_SETTING_ALREADY_DOWNSAMPLED option, to control * the type of upsampling that will be used. * * @param enc encoder object. * @param factor upsampling factor to configure (1, 2, 4 or 8; for 1 this * function has no effect at all) * @param mode upsampling mode to use for this upsampling: * -1: default (good for photographic images, no signaling overhead) * 0: nearest neighbor (good for pixel art) * 1: 'pixel dots' (same as NN for 2x, diamond-shaped 'pixel dots' for 4x/8x) * @return ::JXL_ENC_SUCCESS if the operation was successful, * ::JXL_ENC_ERROR otherwise
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetUpsamplingMode(JxlEncoder* enc,
int64_t factor,
int64_t mode);
/** * Initializes a @ref JxlExtraChannelInfo struct to default values. * For forwards-compatibility, this function has to be called before values * are assigned to the struct fields. * The default values correspond to an 8-bit channel of the provided type. * * @param type type of the extra channel. * @param info global extra channel metadata. Object owned by the caller and its * contents are copied internally.
*/
JXL_EXPORT void JxlEncoderInitExtraChannelInfo(JxlExtraChannelType type,
JxlExtraChannelInfo* info);
/** * Sets information for the extra channel at the given index. The index * must be smaller than num_extra_channels in the associated @ref JxlBasicInfo. * * @param enc encoder object * @param index index of the extra channel to set. * @param info global extra channel metadata. Object owned by the caller and its * contents are copied internally. * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelInfo(
JxlEncoder* enc, size_t index, const JxlExtraChannelInfo* info);
/** * Sets the name for the extra channel at the given index in UTF-8. The index * must be smaller than the num_extra_channels in the associated @ref * JxlBasicInfo. * * TODO(lode): remove size parameter for consistency with * @ref JxlEncoderSetFrameName * * @param enc encoder object * @param index index of the extra channel to set. * @param name buffer with the name of the extra channel. * @param size size of the name buffer in bytes, not counting the terminating * character. * @return JXL_ENC_SUCCESS on success, JXL_ENC_ERROR on error
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelName(JxlEncoder* enc,
size_t index, constchar* name,
size_t size);
/** * Sets a frame-specific option of integer type to the encoder options. * The @ref JxlEncoderFrameSettingId argument determines which option is set. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param option ID of the option to set. * @param value Integer value to set for this option. * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref * JXL_ENC_ERROR in case of an error, such as invalid or unknown option id, or * invalid integer value for the given option. If an error is returned, the * state of the * @ref JxlEncoderFrameSettings object is still valid and is the same as before * this function was called.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderFrameSettingsSetOption(
JxlEncoderFrameSettings* frame_settings, JxlEncoderFrameSettingId option,
int64_t value);
/** * Sets a frame-specific option of float type to the encoder options. * The @ref JxlEncoderFrameSettingId argument determines which option is set. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param option ID of the option to set. * @param value Float value to set for this option. * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref * JXL_ENC_ERROR in case of an error, such as invalid or unknown option id, or * invalid integer value for the given option. If an error is returned, the * state of the * @ref JxlEncoderFrameSettings object is still valid and is the same as before * this function was called.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderFrameSettingsSetFloatOption(
JxlEncoderFrameSettings* frame_settings, JxlEncoderFrameSettingId option, float value);
/** Forces the encoder to use the box-based container format (BMFF) even * when not necessary. * * When using @ref JxlEncoderUseBoxes, @ref JxlEncoderStoreJPEGMetadata or @ref * JxlEncoderSetCodestreamLevel with level 10, the encoder will automatically * also use the container format, it is not necessary to use * @ref JxlEncoderUseContainer for those use cases. * * By default this setting is disabled. * * This setting can only be set at the beginning, before encoding starts. * * @param enc encoder object. * @param use_container true if the encoder should always output the JPEG XL * container format, false to only output it when necessary. * @return JXL_ENC_SUCCESS if the operation was successful, JXL_ENC_ERROR * otherwise.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderUseContainer(JxlEncoder* enc,
JXL_BOOL use_container);
/** * Configure the encoder to store JPEG reconstruction metadata in the JPEG XL * container. * * If this is set to true and a single JPEG frame is added, it will be * possible to losslessly reconstruct the JPEG codestream. * * This setting can only be set at the beginning, before encoding starts. * * @param enc encoder object. * @param store_jpeg_metadata true if the encoder should store JPEG metadata. * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref * JXL_ENC_ERROR otherwise.
*/
JXL_EXPORT JxlEncoderStatus
JxlEncoderStoreJPEGMetadata(JxlEncoder* enc, JXL_BOOL store_jpeg_metadata);
/** Sets the feature level of the JPEG XL codestream. Valid values are 5 and * 10, or -1 (to choose automatically). Using the minimum required level, or * level 5 in most cases, is recommended for compatibility with all decoders. * * Level 5: for end-user image delivery, this level is the most widely * supported level by image decoders and the recommended level to use unless a * level 10 feature is absolutely necessary. Supports a maximum resolution * 268435456 pixels total with a maximum width or height of 262144 pixels, * maximum 16-bit color channel depth, maximum 120 frames per second for * animation, maximum ICC color profile size of 4 MiB, it allows all color * models and extra channel types except CMYK and the JXL_CHANNEL_BLACK * extra channel, and a maximum of 4 extra channels in addition to the 3 color * channels. It also sets boundaries to certain internally used coding tools. * * Level 10: this level removes or increases the bounds of most of the level * 5 limitations, allows CMYK color and up to 32 bits per color channel, but * may be less widely supported. * * The default value is -1. This means the encoder will automatically choose * between level 5 and level 10 based on what information is inside the @ref * JxlBasicInfo structure. Do note that some level 10 features, particularly * those used by animated JPEG XL codestreams, might require level 10, even * though the @ref JxlBasicInfo only suggests level 5. In this case, the level * must be explicitly set to 10, otherwise the encoder will return an error. * The encoder will restrict internal encoding choices to those compatible with * the level setting. * * This setting can only be set at the beginning, before encoding starts. * * @param enc encoder object. * @param level the level value to set, must be -1, 5, or 10. * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref * JXL_ENC_ERROR otherwise.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetCodestreamLevel(JxlEncoder* enc, int level);
/** Returns the codestream level required to support the currently configured * settings and basic info. This function can only be used at the beginning, * before encoding starts, but after setting basic info. * * This does not support per-frame settings, only global configuration, such as * the image dimensions, that are known at the time of writing the header of * the JPEG XL file. * * If this returns 5, nothing needs to be done and the codestream can be * compatible with any decoder. If this returns 10, @ref * JxlEncoderSetCodestreamLevel has to be used to set the codestream level to * 10, or the encoder can be configured differently to allow using the more * compatible level 5. * * @param enc encoder object. * @return -1 if no level can support the configuration (e.g. image dimensions * larger than even level 10 supports), 5 if level 5 is supported, 10 if setting * the codestream level to 10 is required. *
*/
JXL_EXPORT int JxlEncoderGetRequiredCodestreamLevel(const JxlEncoder* enc);
/** * Enables lossless encoding. * * This is not an option like the others on itself, but rather while enabled it * overrides a set of existing options (such as distance, modular mode and * color transform) that enables bit-for-bit lossless encoding. * * When disabled, those options are not overridden, but since those options * could still have been manually set to a combination that operates losslessly, * using this function with lossless set to ::JXL_FALSE does not * guarantee lossy encoding, though the default set of options is lossy. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param lossless whether to override options for lossless mode * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref * JXL_ENC_ERROR otherwise.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetFrameLossless(
JxlEncoderFrameSettings* frame_settings, JXL_BOOL lossless);
/** * Sets the distance level for lossy compression: target max butteraugli * distance, lower = higher quality. Range: 0 .. 25. * 0.0 = mathematically lossless (however, use @ref JxlEncoderSetFrameLossless * instead to use true lossless, as setting distance to 0 alone is not the only * requirement). 1.0 = visually lossless. Recommended range: 0.5 .. 3.0. Default * value: 1.0. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param distance the distance value to set. * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref * JXL_ENC_ERROR otherwise.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetFrameDistance(
JxlEncoderFrameSettings* frame_settings, float distance);
/** * Sets the distance level for lossy compression of extra channels. * The distance is as in @ref JxlEncoderSetFrameDistance (lower = higher * quality). If not set, or if set to the special value -1, the distance that * was set with * @ref JxlEncoderSetFrameDistance will be used. * * @param frame_settings set of options and metadata for this frame. Also * includes reference to the encoder object. * @param index index of the extra channel to set a distance value for. * @param distance the distance value to set. * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref * JXL_ENC_ERROR otherwise.
*/
JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelDistance(
JxlEncoderFrameSettings* frame_settings, size_t index, float distance);
/** * Maps JPEG-style quality factor to distance. * * This function takes in input a JPEG-style quality factor `quality` and * produces as output a `distance` value suitable to be used with @ref * JxlEncoderSetFrameDistance and @ref JxlEncoderSetExtraChannelDistance. * * The `distance` value influences the level of compression, with lower values * indicating higher quality: * - 0.0 implies lossless compression (however, note that calling @ref * JxlEncoderSetFrameLossless is required). * - 1.0 represents a visually lossy compression, which is also the default * setting. * * The `quality` parameter, ranging up to 100, is inversely related to * 'distance': * - A `quality` of 100.0 maps to a `distance` of 0.0 (lossless). * - A `quality` of 90.0 corresponds to a `distance` of 1.0. * * Recommended Range: * - `distance`: 0.5 to 3.0. * - corresponding `quality`: approximately 96 to 68. * * Allowed Range: * - `distance`: 0.0 to 25.0.
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