mirror of
https://github.com/arcodange-org/mediabunny.git
synced 2026-10-02 13:23:51 +02:00
Refactor HLS API: Get rid of specialized Manifest* classes, use Input instead. Add unhydrated InputTracks, InputTrack compatibility, InputTrack queries
This commit is contained in:
Vanilagy
@@ -0,0 +1,331 @@
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import { AES_128_BLOCK_SIZE } from '../aes';
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import { Segment, SegmentEncryptionInfo, SegmentLocation } from '../segment';
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import { SegmentedInput } from '../segmented-input';
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import { AsyncMutex, binarySearchLessOrEqual, toDataView, joinPaths, last } from '../misc';
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import { LineReader, Reader } from '../reader';
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import { HlsDemuxer } from './hls-demuxer';
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import { AttributeList, canIgnoreLine } from './hls-misc';
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const IV_STRING_REGEX = /^0[xX][0-9a-fA-F]+$/;
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export class HlsSegmentedInput extends SegmentedInput {
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_demuxer: HlsDemuxer;
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_lineReader: LineReader;
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_segments: Segment[] = [];
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_nextSegmentDuration: number | null = null;
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_nextSegmentTitle: string | null = null;
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_accumulatedTime = 0;
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_headerRead = false;
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_mutex = new AsyncMutex();
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_currentKey: SegmentEncryptionInfo | null = null;
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_nextSequenceNumber = 0;
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_currentFirstSegment: Segment | null = null;
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_currentInitSegment: Segment | null = null;
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_lastByteRangeEnd: number | null = null;
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_nextByteRange: { offset: number; length: number } | null = null;
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/** @internal */
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constructor(
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demuxer: HlsDemuxer,
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path: string,
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reader: Reader | null,
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) {
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super(demuxer.input, path);
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this._demuxer = demuxer;
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if (reader) {
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this._lineReader = new LineReader(() => reader, canIgnoreLine);
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} else {
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this._lineReader = new LineReader(async () => {
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const source = await this._demuxer.input._getSourceUncached({ path: this.path });
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return new Reader(source);
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}, canIgnoreLine);
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}
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}
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async getFirstSegment() {
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if (this._segments.length === 0) {
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await this._readNextSegment();
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}
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return this._segments[0] ?? null;
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}
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async getSegmentAt(relativeTimestamp: number) {
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await this._readUntilSegmentAt(relativeTimestamp);
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const index = binarySearchLessOrEqual(this._segments, relativeTimestamp, x => x.relativeTimestamp);
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if (index === -1) {
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return null;
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}
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return this._segments[index]!;
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}
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async getNextSegment(segment: Segment) {
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const index = this._segments.indexOf(segment);
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if (index === -1) {
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throw new Error('Segment was not created by this variant.');
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}
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if (index + 1 < this._segments.length) {
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return this._segments[index + 1]!;
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}
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if (this._lineReader.reachedEnd) {
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return null;
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}
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await this._readNextSegment();
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return this._segments[index + 1] ?? null;
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}
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async getPreviousSegment(segment: Segment): Promise<Segment | null> {
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const index = this._segments.indexOf(segment);
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if (index === -1) {
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throw new Error('Segment was not created by this variant.');
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}
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if (index - 1 >= 0) {
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return this._segments[index - 1]!;
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}
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return null;
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}
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async _readNextSegment() {
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const segmentCount = this._segments.length;
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const release = await this._mutex.acquire();
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try {
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if (segmentCount < this._segments.length) {
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// The next segment has already been read by someone else, great
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return;
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}
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while (true) {
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let line = this._lineReader.readNextLine();
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if (line instanceof Promise) line = await line;
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if (line === null) {
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return;
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}
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if (!this._headerRead) {
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if (line !== '#EXTM3U') {
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throw new Error('Invalid M3U8 file; expected first line to be #EXTM3U.');
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}
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this._headerRead = true;
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continue;
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}
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if (!line.startsWith('#')) {
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if (this._nextSegmentDuration === null) {
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throw new Error('Invalid M3U8 file; a segment must be preceeded by a #EXTINF tag.');
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}
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let key = this._currentKey;
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if (key && !key.iv) {
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// "the Media Sequence Number is to be used as the IV when decrypting a Media Segment, by
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// putting its big-endian binary representation into a 16-octet (128-bit) buffer and padding
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// (on the left) with zeros"
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const iv = new Uint8Array(AES_128_BLOCK_SIZE);
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const view = toDataView(iv);
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view.setUint32(8, Math.floor(this._nextSequenceNumber / (2 ** 32)));
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view.setUint32(12, this._nextSequenceNumber);
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key = { ...key, iv };
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}
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const fullPath = joinPaths(this.path, line);
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const location: SegmentLocation = {
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path: fullPath,
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offset: this._nextByteRange?.offset ?? 0,
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length: this._nextByteRange?.length ?? null,
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};
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const segment = new Segment(
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this,
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location,
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this._accumulatedTime,
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this._nextSegmentDuration,
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this._nextSegmentTitle,
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key,
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this._currentFirstSegment,
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this._currentInitSegment,
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);
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this._segments.push(segment);
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this._accumulatedTime += this._nextSegmentDuration;
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this._nextSequenceNumber++;
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this._currentFirstSegment ??= segment;
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this._nextSegmentDuration = null;
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this._nextSegmentTitle = null;
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if (this._nextByteRange === null) {
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this._lastByteRangeEnd = null;
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} else {
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this._nextByteRange = null;
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}
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return;
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}
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if (line.startsWith('#EXTINF:')) {
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const extinfContent = line.slice(8);
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const commaIndex = extinfContent.indexOf(',');
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const durationStr = commaIndex === -1 ? extinfContent : extinfContent.slice(0, commaIndex);
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const duration = Number(durationStr);
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if (!Number.isFinite(duration) || duration < 0) {
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throw new Error(`Invalid #EXTINF tag duration '${durationStr}'.`);
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}
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const title = commaIndex === -1 ? null : extinfContent.slice(commaIndex + 1).trim() || null;
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this._nextSegmentDuration = duration;
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this._nextSegmentTitle = title;
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} else if (line.startsWith('#EXT-X-MAP:')) {
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const attributes = new AttributeList(line.slice(11));
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const uri = attributes.get('uri');
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if (!uri) {
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throw new Error('Invalid #EXT-X-MAP tag; missing URI attribute.');
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}
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const byteRange = attributes.get('byterange');
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if (byteRange !== null) {
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this._parseAndUpdateByteRange(byteRange);
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}
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const fullPath = joinPaths(this.path, uri);
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const location: SegmentLocation = {
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path: fullPath,
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offset: this._nextByteRange?.offset ?? 0,
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length: this._nextByteRange?.length ?? null,
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};
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if (this._currentKey?.method === 'AES-128' && !this._currentKey.iv) {
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// Required by the spec
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throw new Error('IV attribute must be set on #EXT-X-KEY tag preceding the #EXT-X-MAP tag.');
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}
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const segment = new Segment(
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this,
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location,
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this._accumulatedTime,
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0,
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null,
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this._currentKey,
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null,
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null,
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);
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// Accumulated time and sequence number are not updated in this case
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this._currentInitSegment = segment;
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this._nextSegmentDuration = null;
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this._nextSegmentTitle = null;
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if (this._nextByteRange === null) {
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this._lastByteRangeEnd = null;
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} else {
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this._nextByteRange = null;
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}
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} else if (line.startsWith('#EXT-X-KEY:')) {
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const attributes = new AttributeList(line.slice(11));
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const method = attributes.get('method');
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if (method === 'NONE') {
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this._currentKey = null;
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} else if (method === 'AES-128') {
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const uri = attributes.get('uri');
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if (!uri) {
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throw new Error('Invalid #EXT-X-KEY: AES-128 requires a URI attribute.');
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}
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let iv: Uint8Array | null = null;
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const ivString = attributes.get('iv');
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if (ivString) {
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if (!IV_STRING_REGEX.test(ivString)) {
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throw new Error(`Unsupported IV format '${ivString}'.`);
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}
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let hex = ivString.slice(2);
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hex = hex.padStart(AES_128_BLOCK_SIZE * 2, '0');
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iv = new Uint8Array(AES_128_BLOCK_SIZE);
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for (let i = 0; i < AES_128_BLOCK_SIZE; i++) {
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const startIndex = -AES_128_BLOCK_SIZE * 2 + i;
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iv[i] = parseInt(hex.slice(startIndex, startIndex + 2), 16);
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}
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}
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this._currentKey = {
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method: 'AES-128',
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keyUri: joinPaths(this.path, uri),
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iv,
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keyFormat: attributes.get('keyformat') ?? 'identity',
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};
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} else {
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throw new Error(`Unsupported encryption method '${method}'.`);
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}
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} else if (line.startsWith('#EXT-X-MEDIA-SEQUENCE:')) {
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const value = line.slice(22);
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const number = Number(value);
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if (!Number.isInteger(number) || number < 0) {
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throw new Error(`Invalid EXT-X-MEDIA-SEQUENCE value '${value}'.`);
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}
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this._nextSequenceNumber = number;
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} else if (line.startsWith('#EXT-X-BYTERANGE:')) {
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this._parseAndUpdateByteRange(line.slice(17));
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} else if (line.startsWith('#EXT-X-DISCONTINUITY')) {
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this._currentFirstSegment = null;
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this._currentInitSegment = null;
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}
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}
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} finally {
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release();
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}
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}
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_parseAndUpdateByteRange(content: string) {
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const atIndex = content.indexOf('@');
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const length = Number(atIndex === -1 ? content : content.slice(0, atIndex));
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if (!Number.isInteger(length) || length < 0) {
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throw new Error(`Invalid #EXT-X-BYTERANGE length '${content}'.`);
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}
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let offset: number;
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if (atIndex !== -1) {
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offset = Number(content.slice(atIndex + 1));
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if (!Number.isInteger(offset) || offset < 0) {
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throw new Error(`Invalid #EXT-X-BYTERANGE offset '${content}'.`);
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}
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} else {
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if (this._lastByteRangeEnd === null) {
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throw new Error(
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'Invalid M3U8 file; #EXT-X-BYTERANGE without offset requires a previous byte range.',
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);
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}
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offset = this._lastByteRangeEnd;
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}
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this._nextByteRange = { offset, length };
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this._lastByteRangeEnd = offset + length;
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}
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async _readUntilSegmentAt(relativeTimestamp: number) {
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while (!this._lineReader.reachedEnd) {
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const lastSegment = last(this._segments);
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if (lastSegment && lastSegment.relativeTimestamp > relativeTimestamp) {
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break;
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}
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await this._readNextSegment();
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}
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}
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}
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