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Merge changes from v0.14.1
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Rob Walch committed Jul 13, 2020
1 parent c789bd8 commit 86c63bb
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Showing 3 changed files with 55 additions and 38 deletions.
1 change: 1 addition & 0 deletions .github/stale.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@ exemptLabels:
- pinned
- security
- Confirmed
- Chore
- Enhancement
- Feature proposal
- Question
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2 changes: 2 additions & 0 deletions src/controller/stream-controller.ts
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Expand Up @@ -967,6 +967,8 @@ export default class StreamController extends BaseStreamController implements Ne
// Avoid buffering if backtracking this fragment
if (video) {
if (level.details && _hasDroppedFrames(frag, video.dropped, level.details.startSN)) {
// Clear demuxer to reset nextAvc which could have been set for dropped frames
this.resetTransmuxer();
this.backtrack(frag, video.startPTS);
return;
} else {
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90 changes: 52 additions & 38 deletions src/remux/mp4-remuxer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -189,7 +189,7 @@ export default class MP4Remuxer implements Remuxer {
};
if (computePTSDTS) {
// remember first PTS of this demuxing context. for audio, PTS = DTS
initPTS = initDTS = audioSamples[0].pts - audioTrack.inputTimeScale * timeOffset;
initPTS = initDTS = audioSamples[0].pts - Math.round(audioTrack.inputTimeScale * timeOffset);
}
}

Expand All @@ -208,8 +208,9 @@ export default class MP4Remuxer implements Remuxer {
}
};
if (computePTSDTS) {
initPTS = Math.min(initPTS, videoSamples[0].pts - inputTimeScale * timeOffset);
initDTS = Math.min(initDTS, videoSamples[0].dts - inputTimeScale * timeOffset);
const startPTS = Math.round(inputTimeScale * timeOffset);
initPTS = Math.min(initPTS, videoSamples[0].pts - startPTS);
initDTS = Math.min(initDTS, videoSamples[0].dts - startPTS);
}
}

Expand All @@ -235,6 +236,8 @@ export default class MP4Remuxer implements Remuxer {
const initPTS: number = this._initPTS;
let nextAvcDts = this.nextAvcDts;
let offset = 8;
let minPTS: number = Number.MAX_SAFE_INTEGER;
let maxPTS: number = -Number.MAX_SAFE_INTEGER;
let mp4SampleDuration!: number;

// Safari does not like overlapping DTS on consecutive fragments. let's use nextAvcDts to overcome this if fragments are consecutive
Expand Down Expand Up @@ -262,51 +265,54 @@ export default class MP4Remuxer implements Remuxer {
inputSamples.forEach(function (sample) {
sample.pts = PTSNormalize(sample.pts - initPTS, nextAvcDts);
sample.dts = PTSNormalize(sample.dts - initPTS, nextAvcDts);
minPTS = Math.min(sample.pts, minPTS);
maxPTS = Math.max(sample.pts, maxPTS);
});

// handle broken streams with PTS < DTS, tolerance up 200ms (18000 in 90kHz timescale)
const PTSDTSshift = inputSamples.reduce((prev, curr) => Math.max(Math.min(prev, curr.pts - curr.dts), -18000), 0);
if (PTSDTSshift < 0) {
logger.log(`[mp4-remuxer]: PTS < DTS detected in video samples, shifting DTS by ${Math.round(PTSDTSshift / 90)} ms to overcome this issue`);
for (let i = 0; i < inputSamples.length; i++) {
inputSamples[i].dts += PTSDTSshift;
}
}

const firstSample = inputSamples[0];
let firstDTS = Math.max(firstSample.dts, 0);
let firstPTS = Math.max(firstSample.pts, 0);
// Get first/last DTS
let firstDTS = inputSamples[0].dts;
const lastDTS = inputSamples[inputSamples.length - 1].dts;

// Check timestamp continuity across consecutive fragments, and modify timing in order to remove gaps or overlaps.
const millisecondDelta = Math.round((firstDTS - nextAvcDts) / 90);
if (contiguous) {
if (millisecondDelta) {
if (millisecondDelta > 1) {
logger.log(`[mp4-remuxer]: AVC:${millisecondDelta} ms hole between fragments detected,filling it`);
} else if (millisecondDelta < -1) {
logger.log(`[mp4-remuxer]: AVC:${(-millisecondDelta)} ms overlapping between fragments detected`);
const delta = firstDTS - nextAvcDts;
const foundHole = delta > 2;
const foundOverlap = delta < -1;
if (foundHole || foundOverlap) {
const millisecondDelta = Math.round(delta / 90);
if (foundHole) {
logger.warn(`AVC: ${millisecondDelta}ms (${delta}dts) hole between fragments detected, filling it`);
} else {
logger.warn(`AVC: ${-millisecondDelta}ms (${delta}dts) overlapping between fragments detected`);
}

// remove hole/gap : set DTS to next expected DTS
firstSample.dts = firstDTS = nextAvcDts;
firstSample.pts = firstPTS = Math.max(firstSample.pts - millisecondDelta, nextAvcDts);
// offset PTS as well, ensure that PTS is smaller or equal than new DTS
logger.log(`[mp4-remuxer]: Video/PTS/DTS adjusted: ${Math.round(firstSample.pts / 90)}/${Math.round(firstDTS / 90)}, delta:${millisecondDelta} ms`);
firstDTS = nextAvcDts;
minPTS -= delta;
inputSamples[0].dts = firstDTS;
inputSamples[0].pts = minPTS;
logger.log(`Video: PTS/DTS adjusted: ${Math.round(minPTS / 90)}/${Math.round(firstDTS / 90)}, delta: ${millisecondDelta} ms`);
}
}

// compute lastPTS/lastDTS
const lastSample = inputSamples[inputSamples.length - 1];
const lastDTS = Math.max(lastSample.dts, 0);
const lastPTS = Math.max(lastSample.pts, 0, lastDTS);

// on Safari let's signal the same sample duration for all samples
// sample duration (as expected by trun MP4 boxes), should be the delta between sample DTS
// set this constant duration as being the avg delta between consecutive DTS.
if (isSafari) {
mp4SampleDuration = Math.round((lastDTS - firstDTS) / (inputSamples.length - 1));
}

// handle broken streams with PTS < DTS, tolerance up 200ms (18000 in 90kHz timescale)
const PTSDTSshift = inputSamples.reduce((prev, curr) => Math.max(Math.min(prev, curr.pts - curr.dts), -18000), 0);
if (PTSDTSshift < 0) {
logger.warn(`[mp4-remuxer]: PTS < DTS detected in video samples, shifting DTS by ${Math.round(PTSDTSshift / 90)} ms to overcome this issue`);
for (let i = 0; i < inputSamples.length; i++) {
inputSamples[i].dts = Math.max(0, inputSamples[i].dts + PTSDTSshift);
}
}

// Clamp first DTS to 0 so that we're still aligning on initPTS,
// and not passing negative values to MP4.traf. This will change initial frame compositionTimeOffset!
firstDTS = Math.max(inputSamples[0].dts, 0);

let nbNalu = 0;
let naluLen = 0;
for (let i = 0; i < nbSamples; i++) {
Expand Down Expand Up @@ -386,7 +392,7 @@ export default class MP4Remuxer implements Remuxer {
// If so, playback would potentially get stuck, so we artificially inflate
// the duration of the last frame to minimize any potential gap between segments.
const gapTolerance = Math.floor(config.maxBufferHole * timeScale);
const deltaToFrameEnd = (audioTrackLength ? firstPTS + audioTrackLength * timeScale : this.nextAudioPts) - avcSample.pts;
const deltaToFrameEnd = (audioTrackLength ? minPTS + audioTrackLength * timeScale : this.nextAudioPts) - avcSample.pts;
if (deltaToFrameEnd > gapTolerance) {
// We subtract lastFrameDuration from deltaToFrameEnd to try to prevent any video
// frame overlap. maxBufferHole should be >> lastFrameDuration anyway.
Expand Down Expand Up @@ -429,8 +435,8 @@ export default class MP4Remuxer implements Remuxer {
const data = {
data1: moof,
data2: mdat,
startPTS: firstPTS / timeScale,
endPTS: (lastPTS + mp4SampleDuration) / timeScale,
startPTS: minPTS / timeScale,
endPTS: (maxPTS + mp4SampleDuration) / timeScale,
startDTS: firstDTS / timeScale,
endDTS: nextAvcDts / timeScale,
type,
Expand Down Expand Up @@ -518,9 +524,17 @@ export default class MP4Remuxer implements Remuxer {

// If we're overlapping by more than a duration, drop this sample
if (delta <= -maxAudioFramesDrift * inputSampleDuration) {
logger.warn(`[mp4-remuxer]: Dropping 1 audio frame @ ${(nextPts / inputTimeScale).toFixed(3)}s due to ${Math.round(duration)} ms overlap.`);
inputSamples.splice(i, 1);
// Don't touch nextPtsNorm or i
if (contiguous) {
logger.warn(`[mp4-remuxer]: Dropping 1 audio frame @ ${(nextPts / inputTimeScale).toFixed(3)}s due to ${Math.round(duration)} ms overlap.`);
inputSamples.splice(i, 1);
// Don't touch nextPtsNorm or i
} else {
// When changing qualities we can't trust that audio has been appended up to nextAudioPts
// Warn about the overlap but do not drop samples as that can introduce buffer gaps
logger.warn(`Audio frame @ ${(pts / inputTimeScale).toFixed(3)}s overlaps nextAudioPts by ${Math.round(1000 * delta / inputTimeScale)} ms.`);
nextPts = pts + inputSampleDuration;
i++;
}
} // eslint-disable-line brace-style

// Insert missing frames if:
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