/**
This test captures loopback device audio to test that a media element produces audiooutput soon after a setSinkId() call after looping. In bug 1838756,
incorrect timekeeping caused silence in the output as long as the duration of
loops completed.
**/
add_task(async () => {
const audio = new Audio(); audio.src = "sin-441-1s-44100.flac"; audio.loop = true; audio.controls = true;
// Mute initially so that delayed audio from before setSinkId does not
// trigger a false pass. audio.muted = true;
document.body.appendChild(audio);
const canplaythroughPromise = new Promise(r => audio.oncanplaythrough = r);
// Let the audio loop at least twice, which would result in 2 extra seconds
// of silence with bug 1838756.
let count = 0;
const loopedPromise = new Promise(r => audio.onseeked = () => {
if (++count == 2) {
r();
}
});
await loopedPromise;
await audio.setSinkId(outputDeviceInfo.deviceId); audio.muted = false;
// Use a new ScriptProcessor so that the first audioprocess event provides
// the rendering thread time after unmuting.
const processor2 = ac.createScriptProcessor(4096, 1, 0);
loopbackNode.connect(processor2);
let seenAudioCount = 0;
let lastSample, firstTime;
while (seenAudioCount < ac.sampleRate) {
const event = await new Promise(r => processor2.onaudioprocess = r);
let samples = event.inputBuffer.getChannelData(0);
for (const sample of samples) {
if (!seenAudioCount) {
if (!firstTime) {
firstTime = event.playbackTime;
}
if (sample != 0.0) {
seenAudioCount = 1;
} else {
const delay = event.playbackTime - firstTime;
if (delay > 1.0) {
ok(false, `${delay} seconds passed without receiving audio`);
return;
}
}
} else if (sample != 0.0) {
++seenAudioCount;
} else if (lastSample == 0.0) {
ok(false, "should not have two consecutive zero sample in audio");
return;
}
lastSample = sample;
}
}
ok(true, "have one continuous second of audio");
} finally {
if (loopbackNode) {
loopbackNode.disconnect();
} audio.pause();
loopbackStream.getTracks()[0].stop();
}
});
</script>
</html>
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