Read #EXT-X-PROGRAM-DATE-TIME, add Unix epoch-offset timestamps, parallelize HLS master playlist resolution

dev/demux.html

@@ -18,28 +18,13 @@
 		});
 
 		const manifest = new Mediabunny.Input({
-			entryPath: 'https://playertest.longtailvideo.com/adaptive/elephants_dream_v4/index.m3u8',
+			entryPath: 'https://playertest.longtailvideo.com/adaptive/elephants_dream_v4/redundant.m3u8',
 			source: ({ path }) => new Mediabunny.UrlSource(path),
 			formats: Mediabunny.ALL_FORMATS,
 		});
 
 		const tracks = await manifest.getTracks();
-		console.log(tracks.map(x => x.languageCode))
+		console.log(tracks)
-
-		function transform(n) {
-			n = BigInt(n);
-
-			let result = 0n;
-			let place = 1n;
-
-			while (n > 0n) {
-				result += (n & 1n) * place; // extract lowest bit
-				n >>= 1n;                   // shift right
-				place *= 10n;               // next decimal digit
-			}
-
-			return result;
-		}
 
 		/*
 		const manifest = new Mediabunny.ManifestInput({

src/adts/adts-demuxer.ts

@@ -206,6 +206,10 @@ class AdtsAudioTrackBacking implements InputAudioTrackBacking {
 		return sampleRate / SAMPLES_PER_AAC_FRAME;
 	}
 
+	getTimestampsAreRelativeToUnixEpoch() {
+		return false;
+	}
+
 	getGroupId() {
 		return this.getId();
 	}

src/flac/flac-demuxer.ts

@@ -558,6 +558,10 @@ class FlacAudioTrackBacking implements InputAudioTrackBacking {
 		return this.demuxer.audioInfo.sampleRate;
 	}
 
+	getTimestampsAreRelativeToUnixEpoch() {
+		return false;
+	}
+
 	getGroupId() {
 		return this.getId();
 	}

src/hls/hls-demuxer.ts

@@ -80,6 +80,8 @@ export class HlsDemuxer extends Demuxer {
 				lineNumber: number;
 			}[] = [];
 
+			// Let's first iterate through the entire file, collecting all variant streams and media tags
+
 			while (true) {
 				let line = this.lineReader.readNextLine();
 				if (line instanceof Promise) line = await line;
@@ -170,27 +172,11 @@ export class HlsDemuxer extends Demuxer {
 					.filter(tag => tag.attributes.get('type')!.toLowerCase() === 'audio')
 					.map(tag => tag.attributes.get('group-id')!)),
 			];
-			const internalTracks: InternalTrack[] = [];
 
-			const addInternalTrack = (track: InternalTrack, canMerge: boolean) => {
+			// Now, let's process & resolve all variant streams in parallel, mapping each of them to tracks.
-				const existingTrack = internalTracks.find(x =>
-					x.fullPath === track.fullPath && x.info.type === track.info.type && x.groupId === track.groupId,
-				);
-				if (existingTrack && canMerge) {
-					existingTrack.pairingMask |= track.pairingMask;
-					existingTrack.default ||= track.default;
-					existingTrack.lineNumber = Math.min(existingTrack.lineNumber, track.lineNumber);
 
-					if (existingTrack.languageCode === UNDETERMINED_LANGUAGE) {
+			const internalTracksByVariant = await Promise.all(variantStreams.map(async (variantStream, i) => {
-						existingTrack.languageCode = track.languageCode;
+				const result: { track: InternalTrack; canMerge: boolean }[] = [];
-					}
-				} else {
-					internalTracks.push(track);
-				}
-			};
-
-			for (let i = 0; i < variantStreams.length; i++) {
-				const variantStream = variantStreams[i]!;
 
 				const codecsList = variantStream.attributes.get('codecs');
 				let codecStrings: string[];
@@ -198,6 +184,7 @@ export class HlsDemuxer extends Demuxer {
 				if (codecsList) {
 					codecStrings = codecsList.split(',').map(x => x.trim());
 				} else {
+					// No codecs were specified, we need to read the underlying media data
 					const segmentedInput = this.getSegmentedInputForPath(variantStream.fullPath);
 					const input = segmentedInput.toInput();
 					const tracks = await input.getTracks();
@@ -211,8 +198,16 @@ export class HlsDemuxer extends Demuxer {
 
 				const videoGroupId = variantStream.attributes.get('video');
 				const audioGroupId = variantStream.attributes.get('audio');
+				const containsVideoCodecs = codecStrings.some(x =>
+					VIDEO_CODECS.includes(inferCodecFromCodecString(x) as VideoCodec),
+				);
+				const containsAudioCodecs = codecStrings.some(x =>
+					AUDIO_CODECS.includes(inferCodecFromCodecString(x) as AudioCodec),
+				);
+
+				if (videoGroupId !== null && !containsVideoCodecs) {
+					// A video group is linked but no video codec is listed, sigh. Let's resolve the video codec.
 
-				if (videoGroupId !== null) {
 					if (!videoGroupIds.includes(videoGroupId)) {
 						throw new Error(
 							`Invalid M3U8 file; variant stream references video group "${videoGroupId}" which`
@@ -220,32 +215,40 @@ export class HlsDemuxer extends Demuxer {
 						);
 					}
 
-					for (const mediaTag of mediaTags) {
+					const matchingVideoMediaTags = mediaTags.filter((mediaTag) => {
 						const groupId = mediaTag.attributes.get('group-id')!;
 						const type = mediaTag.attributes.get('type')!;
+						return groupId === videoGroupId && type.toLowerCase() === 'video';
+					});
 
-						if (groupId !== videoGroupId || type.toLowerCase() !== 'video') {
+					const additionalCodecStrings = await Promise.all(matchingVideoMediaTags.map(async (tag) => {
-							continue;
+						const uri = tag.attributes.get('uri');
+						if (uri === null) {
+							return null;
 						}
 
-						const uri = mediaTag.attributes.get('uri');
+						const fullPath = joinPaths(this.input._entryPath!, uri);
-						if (uri !== null) {
+						const segmentedInput = this.getSegmentedInputForPath(fullPath);
-							const fullPath = joinPaths(this.input._entryPath, uri);
+						const input = segmentedInput.toInput();
-							const segmentedInput = this.getSegmentedInputForPath(fullPath);
+						const videoTrack = await input.getPrimaryVideoTrack();
-							const input = segmentedInput.toInput();
-							const videoTrack = await input.getPrimaryVideoTrack();
 
-							if (videoTrack && videoTrack.codec !== null) {
+						if (!videoTrack || videoTrack.codec === null) {
-								const codecParameterString = await videoTrack.getCodecParameterString();
+							return null;
-								assert(codecParameterString !== null);
-
-								codecStrings.push(codecParameterString);
-							}
 						}
-					}
+
+						const codecParameterString = await videoTrack.getCodecParameterString();
+						assert(codecParameterString !== null);
+						return codecParameterString;
+					}));
+
+					codecStrings.push(
+						...additionalCodecStrings.filter((x): x is string => x !== null),
+					);
 				}
 
-				if (audioGroupId !== null) {
+				if (audioGroupId !== null && !containsAudioCodecs) {
+					// An audio group is linked but no audio codec is listed, sigh. Let's resolve the audio codec.
+
 					if (!audioGroupIds.includes(audioGroupId)) {
 						throw new Error(
 							`Invalid M3U8 file; variant stream references audio group "${audioGroupId}" which`
@@ -253,29 +256,35 @@ export class HlsDemuxer extends Demuxer {
 						);
 					}
 
-					for (const mediaTag of mediaTags) {
+					const matchingAudioMediaTags = mediaTags.filter((tag) => {
-						const groupId = mediaTag.attributes.get('group-id')!;
+						const groupId = tag.attributes.get('group-id')!;
-						const type = mediaTag.attributes.get('type')!;
+						const type = tag.attributes.get('type')!;
+						return groupId === audioGroupId && type.toLowerCase() === 'audio';
+					});
 
-						if (groupId !== audioGroupId || type.toLowerCase() !== 'audio') {
+					const additionalCodecStrings = await Promise.all(matchingAudioMediaTags.map(async (tag) => {
-							continue;
+						const uri = tag.attributes.get('uri');
+						if (uri === null) {
+							return null;
 						}
 
-						const uri = mediaTag.attributes.get('uri');
+						const fullPath = joinPaths(this.input._entryPath!, uri);
-						if (uri !== null) {
+						const segmentedInput = this.getSegmentedInputForPath(fullPath);
-							const fullPath = joinPaths(this.input._entryPath, uri);
+						const input = segmentedInput.toInput();
-							const segmentedInput = this.getSegmentedInputForPath(fullPath);
+						const audioTrack = await input.getPrimaryAudioTrack();
-							const input = segmentedInput.toInput();
-							const audioTrack = await input.getPrimaryAudioTrack();
 
-							if (audioTrack && audioTrack.codec !== null) {
+						if (!audioTrack || audioTrack.codec === null) {
-								const codecParameterString = await audioTrack.getCodecParameterString();
+							return null;
-								assert(codecParameterString !== null);
-
-								codecStrings.push(codecParameterString);
-							}
 						}
-					}
+
+						const codecParameterString = await audioTrack.getCodecParameterString();
+						assert(codecParameterString !== null);
+						return codecParameterString;
+					}));
+
+					codecStrings.push(
+						...additionalCodecStrings.filter((x): x is string => x !== null),
+					);
 				}
 
 				// Unique that shit
@@ -290,6 +299,7 @@ export class HlsDemuxer extends Demuxer {
 				const averageBandwidth = variantStream.attributes.getAsNumber('average-bandwidth');
 				const name = variantStream.attributes.get('name');
 
+				// Now, finally, loop over each codec string for the variant and resolve each one to one or more tracks.
 				for (const codecString of codecStrings) {
 					const inferredCodec = inferCodecFromCodecString(codecString);
 					if (inferredCodec === null) {
@@ -321,8 +331,8 @@ export class HlsDemuxer extends Demuxer {
 								}
 							}
 
-							addInternalTrack({
+							result.push({ track: {
-								id: internalTracks.length + 1,
+								id: -1,
 								demuxer: this,
 								inputTrack: null,
 								backingTrack: null,
@@ -341,12 +351,12 @@ export class HlsDemuxer extends Demuxer {
 									width,
 									height,
 								},
-							}, false);
+							}, canMerge: false });
 						} else {
 							if (!videoGroupIds.includes(videoGroupId)) {
 								throw new Error(
-									`Invalid M3U8 file; variant stream references video group "${videoGroupId}" which`
+									`Invalid M3U8 file; variant stream references video group "${videoGroupId}"`
-									+ ` is not defined in any #EXT-X-MEDIA tags.`,
+									+ ` which is not defined in any #EXT-X-MEDIA tags.`,
 								);
 							}
 
@@ -371,8 +381,8 @@ export class HlsDemuxer extends Demuxer {
 									}
 								}
 
-								addInternalTrack({
+								result.push({ track: {
-									id: internalTracks.length + 1,
+									id: -1,
 									demuxer: this,
 									inputTrack: null,
 									backingTrack: null,
@@ -391,7 +401,7 @@ export class HlsDemuxer extends Demuxer {
 										width,
 										height,
 									},
-								}, true);
+								}, canMerge: true });
 							}
 						}
 					} else if (AUDIO_CODECS.includes(inferredCodec as AudioCodec)) {
@@ -412,8 +422,8 @@ export class HlsDemuxer extends Demuxer {
 								? Number(channels)
 								: null;
 
-							addInternalTrack({
+							result.push({ track: {
-								id: internalTracks.length + 1,
+								id: -1,
 								demuxer: this,
 								inputTrack: null,
 								backingTrack: null,
@@ -430,18 +440,18 @@ export class HlsDemuxer extends Demuxer {
 								info: {
 									type: 'audio',
 									numberOfChannels:
-									parsedChannels !== null
+											parsedChannels !== null
-									&& Number.isInteger(parsedChannels)
+											&& Number.isInteger(parsedChannels)
-									&& parsedChannels > 0
+											&& parsedChannels > 0
-										? parsedChannels
+												? parsedChannels
-										: null,
+												: null,
 								},
-							}, false);
+							}, canMerge: false });
 						} else {
 							if (!audioGroupIds.includes(audioGroupId)) {
 								throw new Error(
-									`Invalid M3U8 file; variant stream references audio group "${audioGroupId}" which`
+									`Invalid M3U8 file; variant stream references audio group "${audioGroupId}"`
-									+ ` is not defined in any #EXT-X-MEDIA tags.`,
+									+ ` which is not defined in any #EXT-X-MEDIA tags.`,
 								);
 							}
 
@@ -459,8 +469,8 @@ export class HlsDemuxer extends Demuxer {
 									? Number(channels)
 									: null;
 
-								addInternalTrack({
+								result.push({ track: {
-									id: internalTracks.length + 1,
+									id: -1,
 									demuxer: this,
 									inputTrack: null,
 									backingTrack: null,
@@ -477,17 +487,45 @@ export class HlsDemuxer extends Demuxer {
 									info: {
 										type: 'audio',
 										numberOfChannels:
-										parsedChannels !== null
+												parsedChannels !== null
-										&& Number.isInteger(parsedChannels)
+												&& Number.isInteger(parsedChannels)
-										&& parsedChannels > 0
+												&& parsedChannels > 0
-											? parsedChannels
+													? parsedChannels
-											: null,
+													: null,
 									},
-								}, true);
+								}, canMerge: true });
 							}
 						}
 					}
 				}
+
+				return result;
+			}));
+
+			const internalTracks: InternalTrack[] = [];
+			const addInternalTrack = (track: InternalTrack, canMerge: boolean) => {
+				const existingTrack = internalTracks.find(x =>
+					x.fullPath === track.fullPath && x.info.type === track.info.type && x.groupId === track.groupId,
+				);
+
+				if (existingTrack && canMerge) {
+					existingTrack.pairingMask |= track.pairingMask;
+					existingTrack.default ||= track.default;
+					existingTrack.lineNumber = Math.min(existingTrack.lineNumber, track.lineNumber);
+
+					if (existingTrack.languageCode === UNDETERMINED_LANGUAGE) {
+						existingTrack.languageCode = track.languageCode;
+					}
+				} else {
+					track.id = internalTracks.length + 1;
+					internalTracks.push(track);
+				}
+			};
+
+			for (const variantInternalTracks of internalTracksByVariant) {
+				for (const trackEntry of variantInternalTracks) {
+					addInternalTrack(trackEntry.track, trackEntry.canMerge);
+				}
 			}
 
 			// Order tracks by how they appear in the file
@@ -628,6 +666,14 @@ abstract class HlsInputTrackBacking implements InputTrackBacking {
 		return this.internalTrack.backingTrack._backing.getTimeResolution();
 	}
 
+	getTimestampsAreRelativeToUnixEpoch(): boolean {
+		if (!this.internalTrack.backingTrack) {
+			throw new TrackNotHydratedError();
+		}
+
+		return this.internalTrack.backingTrack._backing.getTimestampsAreRelativeToUnixEpoch();
+	}
+
 	getBitrate(): number | null {
 		return this.internalTrack.peakBitrate;
 	}

src/hls/hls-segmented-input.ts

@@ -1,7 +1,7 @@
 import { AES_128_BLOCK_SIZE } from '../aes';
 import { Segment, SegmentEncryptionInfo, SegmentLocation } from '../segment';
 import { SegmentedInput } from '../segmented-input';
-import { toDataView, joinPaths } from '../misc';
+import { toDataView, joinPaths, last } from '../misc';
 import { LineReader, Reader } from '../reader';
 import { HlsDemuxer } from './hls-demuxer';
 import { AttributeList, canIgnoreLine } from './hls-misc';
@@ -10,7 +10,6 @@ const IV_STRING_REGEX = /^0[xX][0-9a-fA-F]+$/;
 
 export class HlsSegmentedInput extends SegmentedInput {
 	demuxer: HlsDemuxer;
-	segments: Segment[] = [];
 	nextSegmentDuration: number | null = null;
 	nextSegmentTitle: string | null = null;
 	accumulatedTime = 0;
@@ -22,6 +21,7 @@ export class HlsSegmentedInput extends SegmentedInput {
 	currentInitSegment: Segment | null = null;
 	lastByteRangeEnd: number | null = null;
 	nextByteRange: { offset: number; length: number } | null = null;
+	lastProgramDateTimeSeconds: number | null = null;
 
 	constructor(
 		demuxer: HlsDemuxer,
@@ -43,6 +43,8 @@ export class HlsSegmentedInput extends SegmentedInput {
 		}
 
 		this.segmentsPromise ??= (async () => {
+			const segments: Segment[] = [];
+
 			while (true) {
 				let line = lineReader.readNextLine();
 				if (line instanceof Promise) line = await line;
@@ -90,13 +92,14 @@ export class HlsSegmentedInput extends SegmentedInput {
 						this,
 						location,
 						this.accumulatedTime,
+						this.lastProgramDateTimeSeconds !== null,
 						this.nextSegmentDuration,
 						this.nextSegmentTitle,
 						key,
 						this.currentFirstSegment,
 						this.currentInitSegment,
 					);
-					this.segments.push(segment);
+					segments.push(segment);
 					this.accumulatedTime += this.nextSegmentDuration;
 					this.nextSequenceNumber++;
 					this.currentFirstSegment ??= segment;
@@ -151,6 +154,7 @@ export class HlsSegmentedInput extends SegmentedInput {
 						this,
 						location,
 						this.accumulatedTime,
+						this.lastProgramDateTimeSeconds !== null,
 						0,
 						null,
 						this.currentKey,
@@ -218,13 +222,51 @@ export class HlsSegmentedInput extends SegmentedInput {
 					this.nextSequenceNumber = number;
 				} else if (line.startsWith('#EXT-X-BYTERANGE:')) {
 					this.parseAndUpdateByteRange(line.slice(17));
+				} else if (line.startsWith('#EXT-X-PROGRAM-DATE-TIME:')) {
+					const dateTime = line.slice(25);
+					const dateTimeMs = Date.parse(dateTime);
+
+					if (!Number.isFinite(dateTimeMs)) {
+						continue;
+					}
+
+					const dateTimeSeconds = dateTimeMs / 1000;
+					if (this.lastProgramDateTimeSeconds === dateTimeSeconds) {
+						continue;
+					}
+
+					if (this.lastProgramDateTimeSeconds === null && segments.length > 0) {
+						// "If the first EXT-X-PROGRAM-DATE-TIME tag in a Playlist appears after
+						// one or more Media Segment URIs, the client SHOULD extrapolate
+						// backward from that tag (using EXTINF durations and/or media
+						// timestamps) to associate dates with those segments."
+						const lastSegment = last(segments)!;
+						const lastSegmentEnd = lastSegment.relativeTimestamp + lastSegment.duration;
+						const offset = dateTimeSeconds - lastSegmentEnd;
+
+						for (const segment of segments) {
+							segment.relativeTimestamp += offset;
+							segment.relativeToUnixEpoch = true;
+						}
+
+						this.accumulatedTime += offset;
+					}
+
+					this.lastProgramDateTimeSeconds = dateTimeSeconds;
+
+					if (Math.abs(this.accumulatedTime - dateTimeSeconds) >= 1) {
+						// Only snap to the datetime if the current time is sufficiently far away from it. If we always
+						// snapped, we'd lose the sub-second accuracy that's often provided by precise
+						// segment durations.
+						this.accumulatedTime = dateTimeSeconds;
+					}
 				} else if (line.startsWith('#EXT-X-DISCONTINUITY')) {
 					this.currentFirstSegment = null;
 					this.currentInitSegment = null;
 				}
 			}
 
-			return this.segments;
+			return segments;
 		})();
 	}
 

src/input-track.ts

@@ -38,6 +38,7 @@ export interface InputTrackBacking {
 	getName(): string | null;
 	getLanguageCode(): string;
 	getTimeResolution(): number;
+	getTimestampsAreRelativeToUnixEpoch(): boolean;
 	getDisposition(): TrackDisposition;
 	getGroupId(): number;
 	getPairingMask(): bigint;
@@ -156,6 +157,14 @@ export abstract class InputTrack {
 		return this._backing.getTimeResolution();
 	}
 
+	/**
+	 * Whether the timestamps of this track are relative to the Unix epoch (January 1, 1970 00:00:00 UTC). When `true`,
+	 * each timestamp maps to a definitive point in time.
+	 */
+	get timestampsAreRelativeToUnixEpoch() {
+		return this._backing.getTimestampsAreRelativeToUnixEpoch();
+	}
+
 	/** The track's disposition, i.e. information about its intended usage. */
 	get disposition() {
 		return this._backing.getDisposition();

src/isobmff/isobmff-demuxer.ts

@@ -2536,6 +2536,10 @@ abstract class IsobmffTrackBacking implements InputTrackBacking {
 		return this.internalTrack.timescale;
 	}
 
+	getTimestampsAreRelativeToUnixEpoch() {
+		return false;
+	}
+
 	getDisposition() {
 		return this.internalTrack.disposition;
 	}

src/matroska/matroska-demuxer.ts

@@ -1946,6 +1946,10 @@ abstract class MatroskaTrackBacking implements InputTrackBacking {
 		return this.internalTrack.segment.timestampFactor;
 	}
 
+	getTimestampsAreRelativeToUnixEpoch() {
+		return false;
+	}
+
 	getDisposition() {
 		return this.internalTrack.disposition;
 	}

src/mp3/mp3-demuxer.ts

@@ -217,6 +217,10 @@ class Mp3AudioTrackBacking implements InputAudioTrackBacking {
 		return this.demuxer.firstFrameHeader.sampleRate / this.demuxer.firstFrameHeader.audioSamplesInFrame;
 	}
 
+	getTimestampsAreRelativeToUnixEpoch() {
+		return false;
+	}
+
 	getGroupId() {
 		return this.getId();
 	}

src/mpeg-ts/mpeg-ts-demuxer.ts

@@ -1079,6 +1079,10 @@ abstract class MpegTsTrackBacking implements InputTrackBacking {
 		return TIMESCALE;
 	}
 
+	getTimestampsAreRelativeToUnixEpoch() {
+		return false;
+	}
+
 	getGroupId() {
 		return this.getId();
 	}

src/ogg/ogg-demuxer.ts

@@ -444,6 +444,10 @@ class OggAudioTrackBacking implements InputAudioTrackBacking {
 		return this.bitstream.sampleRate;
 	}
 
+	getTimestampsAreRelativeToUnixEpoch() {
+		return false;
+	}
+
 	getGroupId() {
 		return this.getId();
 	}

src/segment.ts

@@ -22,6 +22,7 @@ export class Segment {
 	input: SegmentedInput;
 	location: SegmentLocation;
 	relativeTimestamp: number;
+	relativeToUnixEpoch: boolean;
 	duration: number;
 	title: string | null;
 	encryption: SegmentEncryptionInfo | null;
@@ -32,6 +33,7 @@ export class Segment {
 		input: SegmentedInput,
 		location: SegmentLocation,
 		relativeTimestamp: number,
+		relativeToUnixEpoch: boolean,
 		duration: number,
 		title: string | null,
 		encryption: SegmentEncryptionInfo | null,
@@ -41,6 +43,7 @@ export class Segment {
 		this.input = input;
 		this.location = location;
 		this.relativeTimestamp = relativeTimestamp;
+		this.relativeToUnixEpoch = relativeToUnixEpoch;
 		this.duration = duration;
 		this.title = title;
 		this.encryption = encryption;

src/segmented-input.ts

@@ -21,7 +21,7 @@ import {
 import { Segment } from './segment';
 import { PacketRetrievalOptions } from './media-sink';
 import { MetadataTags, TrackDisposition } from './metadata';
-import { arrayCount, assert, binarySearchLessOrEqual, Rotation } from './misc';
+import { arrayCount, assert, binarySearchLessOrEqual, Rotation, roundToMultiple } from './misc';
 import { EncodedPacket } from './packet';
 import { NullSource } from './source';
 
@@ -255,6 +255,11 @@ class SegmentedInputInputTrackBacking implements InputTrackBacking {
 		return this.firstInputTrack._backing.getTimeResolution();
 	}
 
+	getTimestampsAreRelativeToUnixEpoch(): boolean {
+		assert(this.demuxer.firstSegment);
+		return this.demuxer.firstSegment.relativeToUnixEpoch;
+	}
+
 	getBitrate(): number | null {
 		return this.firstInputTrack._backing.getBitrate();
 	}
@@ -267,7 +272,10 @@ class SegmentedInputInputTrackBacking implements InputTrackBacking {
 		const mediaOffset = await this.demuxer.getMediaOffset(segment, track.input);
 
 		const modified = packet.clone({
-			timestamp: packet.timestamp + mediaOffset,
+			timestamp: roundToMultiple(
+				packet.timestamp + mediaOffset,
+				1 / track.timeResolution,
+			),
 			// The 1e8 assumes a max of 100 MB per second, highly unlikely to be hit, so this should guarantee
 			// monotonically increasing sequence numbers across segments.
 			sequenceNumber: Math.floor(1e8 * segment.relativeTimestamp) + packet.sequenceNumber,

src/wave/wave-demuxer.ts

@@ -394,6 +394,10 @@ class WaveAudioTrackBacking implements InputAudioTrackBacking {
 		return this.demuxer.audioInfo.sampleRate;
 	}
 
+	getTimestampsAreRelativeToUnixEpoch() {
+		return false;
+	}
+
 	getGroupId() {
 		return this.getId();
 	}

testfiles_temp/entry25.m3u8

@@ -0,0 +1,34 @@
+#EXTM3U
+#EXT-X-VERSION:3
+
+#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="Chinese",FORCED=NO,AUTOSELECT=YES,URI="media/chinese/ed.m3u8",LANGUAGE="zh"
+#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="French",FORCED=NO,AUTOSELECT=YES,URI="media/french/ed.m3u8",LANGUAGE="fr"
+
+#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac",LANGUAGE="en",NAME="English",DEFAULT=YES,AUTOSELECT=YES,URI="media/b160000-english.m3u8"
+#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac",LANGUAGE="sp",NAME="Spanish",DEFAULT=NO,AUTOSELECT=YES,URI="media/b160000-spanish.m3u8"
+#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac",LANGUAGE="en",NAME="Commentary (eng)",DEFAULT=NO,AUTOSELECT=NO,URI="media/b160000-commentary.m3u8"
+
+#EXT-X-STREAM-INF:BANDWIDTH=2962000,NAME="Main",CODECS="avc1.66.30",RESOLUTION=1280x720,AUDIO="aac",SUBTITLES="subs"
+media/b2962000-video.m3u8
+#EXT-X-STREAM-INF:BANDWIDTH=1427000,NAME="Main",CODECS="avc1.66.30",RESOLUTION=768x432,AUDIO="aac",SUBTITLES="subs"
+media/b1427000-video.m3u8
+#EXT-X-STREAM-INF:BANDWIDTH=688000,NAME="Main",CODECS="avc1.66.30",RESOLUTION=448x252,AUDIO="aac",SUBTITLES="subs"
+media/b688000-video.m3u8
+#EXT-X-STREAM-INF:BANDWIDTH=331000,NAME="Main",CODECS="avc1.66.30",RESOLUTION=284x160,AUDIO="aac",SUBTITLES="subs"
+media/b331000-video.m3u8
+
+#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs_b",NAME="Chinese",FORCED=NO,AUTOSELECT=YES,URI="media_b/chinese/ed.m3u8",LANGUAGE="zh"
+#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs_b",NAME="French",FORCED=NO,AUTOSELECT=YES,URI="media_b/french/ed.m3u8",LANGUAGE="fr"
+
+#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac_b",LANGUAGE="en",NAME="English",DEFAULT=YES,AUTOSELECT=YES,URI="media_b/b160000-english.m3u8"
+#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac_b",LANGUAGE="sp",NAME="Spanish",DEFAULT=NO,AUTOSELECT=YES,URI="media_b/b160000-spanish.m3u8"
+#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac_b",LANGUAGE="en",NAME="Commentary (eng)",DEFAULT=NO,AUTOSELECT=NO,URI="media_b/b160000-commentary.m3u8"
+
+#EXT-X-STREAM-INF:BANDWIDTH=2962000,NAME="Main",CODECS="avc1.66.30",RESOLUTION=1280x720,AUDIO="aac_b",SUBTITLES="subs_b"
+media_b/b2962000-video.m3u8
+#EXT-X-STREAM-INF:BANDWIDTH=1427000,NAME="Main",CODECS="avc1.66.30",RESOLUTION=768x432,AUDIO="aac_b",SUBTITLES="subs_b"
+media_b/b1427000-video.m3u8
+#EXT-X-STREAM-INF:BANDWIDTH=688000,NAME="Main",CODECS="avc1.66.30",RESOLUTION=448x252,AUDIO="aac_b",SUBTITLES="subs_b"
+media_b/b688000-video.m3u8
+#EXT-X-STREAM-INF:BANDWIDTH=331000,NAME="Main",CODECS="avc1.66.30",RESOLUTION=284x160,AUDIO="aac_b",SUBTITLES="subs_b"
+media_b/b331000-video.m3u8