99cb1c48ea
See comment within. They would be constantly rerequested and av-merge would think it didn't have them, so it wouldn't request subsequent segments Signed-off-by: Jesús <heckyel@hyperbola.info>
590 lines
20 KiB
JavaScript
590 lines
20 KiB
JavaScript
// Heavily modified from
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// https://github.com/nickdesaulniers/netfix/issues/4#issuecomment-578856471
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// which was in turn modified from
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// https://github.com/nickdesaulniers/netfix/blob/gh-pages/demo/bufferWhenNeeded.html
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// Useful reading:
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// https://stackoverflow.com/questions/35177797/what-exactly-is-fragmented-mp4fmp4-how-is-it-different-from-normal-mp4
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// https://axel.isouard.fr/blog/2016/05/24/streaming-webm-video-over-html5-with-media-source
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// We start by parsing the sidx (segment index) table in order to get the
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// byte ranges of the segments. The byte range of the sidx table is provided
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// by the indexRange variable by YouTube
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// Useful info, as well as segments vs sequence mode (we use segments mode)
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// https://joshuatz.com/posts/2020/appending-videos-in-javascript-with-mediasource-buffers/
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// SourceBuffer data limits:
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// https://developers.google.com/web/updates/2017/10/quotaexceedederror
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// TODO: Call abort to cancel in-progress appends?
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function AVMerge(video, srcPair, startTime){
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this.videoSource = srcPair[0];
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this.audioSource = srcPair[1];
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if (this.videoSource.bitrate && this.audioSource.bitrate)
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this.avRatio = this.audioSource.bitrate/this.videoSource.bitrate;
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else
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this.avRatio = 1/10;
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this.videoStream = null;
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this.audioStream = null;
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this.seeking = false;
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this.startTime = startTime;
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this.video = video;
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this.mediaSource = null;
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this.closed = false;
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this.opened = false;
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this.audioEndOfStreamCalled = false;
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this.videoEndOfStreamCalled = false;
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this.setup();
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}
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AVMerge.prototype.setup = function() {
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if ('MediaSource' in window
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&& MediaSource.isTypeSupported(this.audioSource['mime_codec'])
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&& MediaSource.isTypeSupported(this.videoSource['mime_codec'])) {
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this.mediaSource = new MediaSource();
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this.video.src = URL.createObjectURL(this.mediaSource);
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this.mediaSource.onsourceopen = this.sourceOpen.bind(this);
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} else {
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reportError('Unsupported MIME type or codec: ',
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this.audioSource['mime_codec'],
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this.videoSource['mime_codec']);
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}
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}
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AVMerge.prototype.sourceOpen = function(_) {
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// If after calling mediaSource.endOfStream, the user seeks back
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// into the video, the sourceOpen event will be fired again. Do not
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// overwrite the streams.
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this.audioEndOfStreamCalled = false;
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this.videoEndOfStreamCalled = false;
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if (this.opened)
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return;
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this.opened = true;
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this.videoStream = new Stream(this, this.videoSource, this.startTime,
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this.avRatio);
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this.audioStream = new Stream(this, this.audioSource, this.startTime,
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this.avRatio);
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this.videoStream.setup();
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this.audioStream.setup();
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this.timeUpdateEvt = addEvent(this.video, 'timeupdate',
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this.checkBothBuffers.bind(this));
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this.seekingEvt = addEvent(this.video, 'seeking',
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debounce(this.seek.bind(this), 500));
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//this.video.onseeked = function() {console.log('seeked')};
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}
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AVMerge.prototype.close = function() {
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if (this.closed)
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return;
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this.closed = true;
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this.videoStream.close();
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this.audioStream.close();
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this.timeUpdateEvt.remove();
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this.seekingEvt.remove();
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if (this.mediaSource.readyState == 'open')
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this.mediaSource.endOfStream();
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}
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AVMerge.prototype.checkBothBuffers = function() {
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this.audioStream.checkBuffer();
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this.videoStream.checkBuffer();
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}
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AVMerge.prototype.seek = function(e) {
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if (this.mediaSource.readyState === 'open') {
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this.seeking = true;
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this.audioStream.handleSeek();
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this.videoStream.handleSeek();
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this.seeking = false;
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} else {
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reportWarning('seek but not open? readyState:',
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this.mediaSource.readyState);
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}
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}
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AVMerge.prototype.audioEndOfStream = function() {
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if (this.videoEndOfStreamCalled && !this.audioEndOfStreamCalled) {
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reportDebug('Calling mediaSource.endOfStream()');
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this.mediaSource.endOfStream();
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}
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this.audioEndOfStreamCalled = true;
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}
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AVMerge.prototype.videoEndOfStream = function() {
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if (this.audioEndOfStreamCalled && !this.videoEndOfStreamCalled) {
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reportDebug('Calling mediaSource.endOfStream()');
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this.mediaSource.endOfStream();
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}
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this.videoEndOfStreamCalled = true;
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}
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AVMerge.prototype.printDebuggingInfo = function() {
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reportDebug('videoSource:', this.videoSource);
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reportDebug('audioSource:', this.videoSource);
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reportDebug('video sidx:', this.videoStream.sidx);
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reportDebug('audio sidx:', this.audioStream.sidx);
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reportDebug('video duration:', this.video.duration);
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reportDebug('video current time:', this.video.currentTime);
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reportDebug('mediaSource.readyState:', this.mediaSource.readyState);
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reportDebug('videoEndOfStreamCalled', this.videoEndOfStreamCalled);
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reportDebug('audioEndOfStreamCalled', this.audioEndOfStreamCalled);
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for (let obj of [this.videoStream, this.audioStream]) {
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reportDebug(obj.streamType, 'stream buffered times:');
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for (let i=0; i<obj.sourceBuffer.buffered.length; i++) {
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reportDebug(String(obj.sourceBuffer.buffered.start(i)) + '-'
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+ String(obj.sourceBuffer.buffered.end(i)));
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}
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}
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}
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function Stream(avMerge, source, startTime, avRatio) {
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this.avMerge = avMerge;
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this.video = avMerge.video;
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this.url = source['url'];
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this.closed = false;
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this.mimeCodec = source['mime_codec']
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this.streamType = source['acodec'] ? 'audio' : 'video';
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if (this.streamType == 'audio') {
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this.bufferTarget = avRatio*50*10**6;
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} else {
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this.bufferTarget = 50*10**6; // 50 megabytes
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}
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this.initRange = source['init_range'];
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this.indexRange = source['index_range'];
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this.startTime = startTime;
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this.mediaSource = avMerge.mediaSource;
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this.sidx = null;
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this.appendRetries = 0;
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this.appendQueue = []; // list of [segmentIdx, data]
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this.sourceBuffer = this.mediaSource.addSourceBuffer(this.mimeCodec);
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this.sourceBuffer.mode = 'segments';
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this.sourceBuffer.addEventListener('error', (e) => {
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this.reportError('sourceBuffer error', e);
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});
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this.updateendEvt = addEvent(this.sourceBuffer, 'updateend', (e) => {
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if (this.appendQueue.length != 0) {
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this.appendSegment(...this.appendQueue.pop());
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}
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});
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}
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Stream.prototype.setup = async function(){
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// Group requests together
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if (this.initRange.end+1 == this.indexRange.start){
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fetchRange(
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this.url,
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this.initRange.start,
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this.indexRange.end,
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(buffer) => {
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var init_end = this.initRange.end - this.initRange.start + 1;
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var index_start = this.indexRange.start - this.initRange.start;
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var index_end = this.indexRange.end - this.initRange.start + 1;
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this.appendSegment(null, buffer.slice(0, init_end));
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this.setupSegments(buffer.slice(index_start, index_end));
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}
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)
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} else {
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// initialization data
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await fetchRange(
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this.url,
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this.initRange.start,
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this.initRange.end,
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this.appendSegment.bind(this, null),
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);
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// sidx (segment index) table
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fetchRange(
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this.url,
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this.indexRange.start,
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this.indexRange.end,
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this.setupSegments.bind(this)
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);
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}
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}
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Stream.prototype.setupSegments = async function(sidxBox){
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var box = unbox(sidxBox);
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this.sidx = sidx_parse(box.data, this.indexRange.end+1);
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this.fetchSegmentIfNeeded(this.getSegmentIdx(this.startTime));
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}
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Stream.prototype.close = function() {
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// Prevents appendSegment adding to buffer if request finishes
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// after closing
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this.closed = true;
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if (this.sourceBuffer.updating)
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this.sourceBuffer.abort();
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this.mediaSource.removeSourceBuffer(this.sourceBuffer);
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this.updateendEvt.remove();
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}
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Stream.prototype.appendSegment = function(segmentIdx, chunk) {
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if (this.closed)
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return;
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this.reportDebug('Received segment', segmentIdx)
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// cannot append right now, schedule for updateend
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if (this.sourceBuffer.updating) {
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this.reportDebug('sourceBuffer updating, queueing for later');
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this.appendQueue.push([segmentIdx, chunk]);
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if (this.appendQueue.length > 2){
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this.reportWarning('appendQueue length:', this.appendQueue.length);
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}
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return;
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}
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try {
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this.sourceBuffer.appendBuffer(chunk);
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if (segmentIdx !== null)
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this.sidx.entries[segmentIdx].have = true;
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this.appendRetries = 0;
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} catch (e) {
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if (e.name !== 'QuotaExceededError') {
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throw e;
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}
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// Delete 3 segments (arbitrary) from beginning of buffer, making sure
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// not to delete current one
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var currentSegment = this.getSegmentIdx(this.video.currentTime);
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this.reportWarning('QuotaExceededError. Deleting segments.');
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var numDeleted = 0;
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var i = 0;
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while (numDeleted < 3 && i < currentSegment) {
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let entry = this.sidx.entries[i];
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let start = entry.tickStart/this.sidx.timeScale;
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let end = (entry.tickEnd+1)/this.sidx.timeScale;
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if (entry.have) {
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this.reportWarning('Deleting segment', i);
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this.sourceBuffer.remove(start, end);
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}
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}
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}
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}
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Stream.prototype.getSegmentIdx = function(videoTime) {
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// get an estimate
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var currentTick = videoTime * this.sidx.timeScale;
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var firstSegmentDuration = this.sidx.entries[0].subSegmentDuration;
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var index = 1 + Math.floor(currentTick / firstSegmentDuration);
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var index = clamp(index, 0, this.sidx.entries.length - 1);
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var increment = 1;
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if (currentTick < this.sidx.entries[index].tickStart){
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increment = -1;
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}
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// go up or down to find correct index
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while (index >= 0 && index < this.sidx.entries.length) {
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var entry = this.sidx.entries[index];
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if (entry.tickStart <= currentTick && (entry.tickEnd+1) > currentTick){
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return index;
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}
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index = index + increment;
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}
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this.reportError('Could not find segment index for time', videoTime);
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return 0;
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}
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Stream.prototype.checkBuffer = async function() {
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if (this.avMerge.seeking) {
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return;
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}
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// Find the first unbuffered segment, i
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var currentSegmentIdx = this.getSegmentIdx(this.video.currentTime);
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var bufferedBytesAhead = 0;
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var i;
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for (i = currentSegmentIdx; i < this.sidx.entries.length; i++) {
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var entry = this.sidx.entries[i];
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// check if we had it before, but it was deleted by the browser
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if (entry.have && !this.segmentInBuffer(i)) {
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this.reportDebug('segment', i, 'deleted by browser');
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entry.have = false;
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entry.requested = false;
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}
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if (!entry.have) {
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break;
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}
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bufferedBytesAhead += entry.referencedSize;
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if (bufferedBytesAhead > this.bufferTarget) {
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return;
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}
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}
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if (i < this.sidx.entries.length && !this.sidx.entries[i].requested) {
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this.fetchSegment(i);
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// We have all the segments until the end
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// Signal the end of stream
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} else if (i == this.sidx.entries.length) {
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if (this.streamType == 'audio')
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this.avMerge.audioEndOfStream();
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else
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this.avMerge.videoEndOfStream();
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}
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}
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Stream.prototype.segmentInBuffer = function(segmentIdx) {
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var entry = this.sidx.entries[segmentIdx];
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// allow for 0.01 second error
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var timeStart = entry.tickStart/this.sidx.timeScale + 0.01;
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/* Some of YouTube's mp4 fragments are malformed, with half-frame
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playback gaps. In this video at 240p (timeScale = 90000 ticks/second)
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https://www.youtube.com/watch?v=ZhOQCwJvwlo
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segment 4 (starting at 0) is claimed in the sidx table to have
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a duration of 388500 ticks, but closer examination of the file using
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Bento4 mp4dump shows that the segment has 129 frames at 3000 ticks
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per frame, which gives an actual duration of 38700 (1500 less than
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claimed). The file is 30 fps, so this error is exactly half a frame.
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Note that the base_media_decode_time exactly matches the tickStart,
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so the media decoder is being given a time gap of half a frame.
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The practical result of this is that sourceBuffer.buffered reports
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a timeRange.end that is less than expected for that segment, resulting in
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a false determination that the browser has deleted a segment.
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Segment 5 has the opposite issue, where it has a 1500 tick surplus of video
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data compared to the sidx length. Segments 6 and 7 also have this
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deficit-surplus pattern.
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This might have something to do with the fact that the video also
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has 60 fps formats. In order to allow for adaptive streaming and seamless
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quality switching, YouTube likely encodes their formats to line up nicely.
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Either there is a bug in their encoder, or this is intentional. Allow for
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up to 1 frame-time of error to work around this issue. */
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if (this.streamType == 'video')
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var endError = 1/(this.avMerge.videoSource.fps || 30);
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else
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var endError = 0.01
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var timeEnd = (entry.tickEnd+1)/this.sidx.timeScale - endError;
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var timeRanges = this.sourceBuffer.buffered;
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for (var i=0; i < timeRanges.length; i++) {
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if (timeRanges.start(i) <= timeStart && timeEnd <= timeRanges.end(i)) {
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return true;
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}
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}
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return false;
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}
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Stream.prototype.fetchSegment = function(segmentIdx) {
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entry = this.sidx.entries[segmentIdx];
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entry.requested = true;
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this.reportDebug(
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'Fetching segment', segmentIdx, ', bytes',
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entry.start, entry.end, ', seconds',
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entry.tickStart/this.sidx.timeScale,
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(entry.tickEnd+1)/this.sidx.timeScale
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)
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fetchRange(
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this.url,
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entry.start,
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entry.end,
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this.appendSegment.bind(this, segmentIdx),
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);
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}
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Stream.prototype.fetchSegmentIfNeeded = function(segmentIdx) {
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if (segmentIdx < 0 || segmentIdx >= this.sidx.entries.length){
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return;
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}
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entry = this.sidx.entries[segmentIdx];
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// check if we had it before, but it was deleted by the browser
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if (entry.have && !this.segmentInBuffer(segmentIdx)) {
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this.reportDebug('segment', segmentIdx, 'deleted by browser');
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entry.have = false;
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entry.requested = false;
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}
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if (entry.requested) {
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return;
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}
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this.fetchSegment(segmentIdx);
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}
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Stream.prototype.handleSeek = async function() {
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var segmentIdx = this.getSegmentIdx(this.video.currentTime);
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this.fetchSegmentIfNeeded(segmentIdx);
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}
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Stream.prototype.reportDebug = function(...args) {
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reportDebug(String(this.streamType) + ':', ...args);
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}
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Stream.prototype.reportWarning = function(...args) {
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reportWarning(String(this.streamType) + ':', ...args);
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}
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Stream.prototype.reportError = function(...args) {
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reportError(String(this.streamType) + ':', ...args);
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}
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// Utility functions
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function fetchRange(url, start, end, cb) {
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return new Promise((resolve, reject) => {
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var xhr = new XMLHttpRequest();
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xhr.open('get', url);
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xhr.responseType = 'arraybuffer';
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xhr.setRequestHeader('Range', 'bytes=' + start + '-' + end);
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xhr.onload = function() {
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//bytesFetched += end - start + 1;
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resolve(cb(xhr.response));
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};
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xhr.send();
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});
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}
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function debounce(func, wait, immediate) {
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var timeout;
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return function() {
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var context = this;
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var args = arguments;
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var later = function() {
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timeout = null;
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if (!immediate) func.apply(context, args);
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};
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var callNow = immediate && !timeout;
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clearTimeout(timeout);
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timeout = setTimeout(later, wait);
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if (callNow) func.apply(context, args);
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};
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}
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function clamp(number, min, max) {
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return Math.max(min, Math.min(number, max));
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}
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// allow to remove an event listener without having a function reference
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function RegisteredEvent(obj, eventName, func) {
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this.obj = obj;
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this.eventName = eventName;
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this.func = func;
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obj.addEventListener(eventName, func);
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}
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RegisteredEvent.prototype.remove = function() {
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this.obj.removeEventListener(this.eventName, this.func);
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}
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function addEvent(obj, eventName, func) {
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return new RegisteredEvent(obj, eventName, func);
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}
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function reportWarning(...args){
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console.warn(...args);
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}
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function reportError(...args){
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console.error(...args);
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}
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function reportDebug(...args){
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console.debug(...args);
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}
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function byteArrayToIntegerLittleEndian(unsignedByteArray){
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var result = 0;
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for (byte of unsignedByteArray){
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result = result*256;
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result += byte
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}
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return result;
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}
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function ByteParser(data){
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this.curIndex = 0;
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this.data = new Uint8Array(data);
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}
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ByteParser.prototype.readInteger = function(nBytes){
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var result = byteArrayToIntegerLittleEndian(
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this.data.slice(this.curIndex, this.curIndex + nBytes)
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);
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this.curIndex += nBytes;
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return result;
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}
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ByteParser.prototype.readBufferBytes = function(nBytes){
|
|
var result = this.data.slice(this.curIndex, this.curIndex + nBytes);
|
|
this.curIndex += nBytes;
|
|
return result;
|
|
}
|
|
|
|
// BEGIN iso-bmff-parser-stream/lib/box/sidx.js (modified)
|
|
// https://github.com/necccc/iso-bmff-parser-stream/blob/master/lib/box/sidx.js
|
|
/* The MIT License (MIT)
|
|
|
|
Copyright (c) 2014 Szabolcs Szabolcsi-Toth
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
of this software and associated documentation files (the "Software"), to deal
|
|
in the Software without restriction, including without limitation the rights
|
|
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
copies of the Software, and to permit persons to whom the Software is
|
|
furnished to do so, subject to the following conditions:
|
|
|
|
The above copyright notice and this permission notice shall be included in all
|
|
copies or substantial portions of the Software.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
SOFTWARE.*/
|
|
function sidx_parse (data, offset) {
|
|
var bp = new ByteParser(data),
|
|
version = bp.readInteger(1),
|
|
flags = bp.readInteger(3),
|
|
referenceId = bp.readInteger(4),
|
|
timeScale = bp.readInteger(4),
|
|
earliestPresentationTime = bp.readInteger(version === 0 ? 4 : 8),
|
|
firstOffset = bp.readInteger(4),
|
|
__reserved = bp.readInteger(2),
|
|
entryCount = bp.readInteger(2),
|
|
entries = [];
|
|
|
|
var totalBytesOffset = firstOffset + offset;
|
|
var totalTicks = 0;
|
|
for (var i = entryCount; i > 0; i=i-1 ) {
|
|
let referencedSize = bp.readInteger(4),
|
|
subSegmentDuration = bp.readInteger(4),
|
|
unused = bp.readBufferBytes(4)
|
|
entries.push({
|
|
referencedSize: referencedSize,
|
|
subSegmentDuration: subSegmentDuration,
|
|
unused: unused,
|
|
start: totalBytesOffset,
|
|
end: totalBytesOffset + referencedSize - 1, // inclusive
|
|
tickStart: totalTicks,
|
|
tickEnd: totalTicks + subSegmentDuration - 1,
|
|
requested: false,
|
|
have: false,
|
|
});
|
|
totalBytesOffset = totalBytesOffset + referencedSize;
|
|
totalTicks = totalTicks + subSegmentDuration;
|
|
}
|
|
|
|
return {
|
|
version: version,
|
|
flags: flags,
|
|
referenceId: referenceId,
|
|
timeScale: timeScale,
|
|
earliestPresentationTime: earliestPresentationTime,
|
|
firstOffset: firstOffset,
|
|
entries: entries
|
|
};
|
|
}
|
|
// END sidx.js
|
|
|
|
// BEGIN iso-bmff-parser-stream/lib/unbox.js (same license), modified
|
|
function unbox(buf) {
|
|
var bp = new ByteParser(buf),
|
|
bufferLength = buf.length,
|
|
length,
|
|
typeData,
|
|
boxData
|
|
|
|
length = bp.readInteger(4); // length of entire box,
|
|
typeData = bp.readInteger(4);
|
|
|
|
if (bufferLength - length < 0) {
|
|
reportWarning('Warning: sidx table is cut off');
|
|
return {
|
|
currentLength: bufferLength,
|
|
length: length,
|
|
type: typeData,
|
|
data: bp.readBufferBytes(bufferLength)
|
|
};
|
|
}
|
|
|
|
boxData = bp.readBufferBytes(length - 8);
|
|
|
|
return {
|
|
length: length,
|
|
type: typeData,
|
|
data: boxData
|
|
};
|
|
}
|
|
// END unbox.js
|