Multiple miscellaneous fixes

src/conversion.ts

@@ -641,7 +641,7 @@ class Conversion {
 			}
 
 			if (needsResample) {
-				audioSource = await this.resampleAudio(track, codecOfChoice, numberOfChannels, sampleRate);
+				audioSource = this.resampleAudio(track, codecOfChoice, numberOfChannels, sampleRate);
 			} else {
 				const source = new AudioDataSource({
 					codec: codecOfChoice,
@@ -654,7 +654,7 @@ class Conversion {
 					await this.started;
 
 					const sink = new AudioDataSink(track);
-					for await (const { data, timestamp } of sink.data(undefined, this.startTimestamp)) {
+					for await (const { data, timestamp } of sink.data(undefined, this.endTimestamp)) {
 						if (this.synchronizer.shouldWait(track.id, timestamp)) {
 							await this.synchronizer.wait(timestamp);
 						}
@@ -686,7 +686,7 @@ class Conversion {
 	 * Resamples the audio by decoding it, playing it onto an OfflineAudioContext and encoding the
 	 * resulting AudioBuffer.
 	 */
-	async resampleAudio(
+	resampleAudio(
 		track: InputAudioTrack,
 		codec: AudioCodec,
 		targetNumberOfChannels: number,

src/isobmff/isobmff-demuxer.ts

@@ -27,7 +27,6 @@ import {
 	COLOR_PRIMARIES_MAP_INVERSE,
 	MATRIX_COEFFICIENTS_MAP_INVERSE,
 	TRANSFER_CHARACTERISTICS_MAP_INVERSE,
-	rotationMatrix,
 	binarySearchLessOrEqual,
 	binarySearchExact,
 	Rotation,
@@ -38,6 +37,8 @@ import {
 	TransformationMatrix,
 	extractRotationFromMatrix,
 	roundToPrecision,
+	isIso639Dash2LanguageCode,
+	roundToMultiple,
 } from '../misc';
 import { Reader } from '../reader';
 import { EncodedAudioSample, EncodedVideoSample, PLACEHOLDER_DATA, SampleType } from '../sample';
@@ -175,8 +176,6 @@ type Fragment = {
 	isKnownToBeFirstFragment: boolean;
 };
 
-const knownMatrixes = [rotationMatrix(0), rotationMatrix(90), rotationMatrix(180), rotationMatrix(270)];
-
 export class IsobmffDemuxer extends Demuxer {
 	metadataReader: IsobmffReader;
 	currentTrack: InternalTrack | null = null;
@@ -657,16 +656,11 @@ export class IsobmffDemuxer extends Demuxer {
 					this.metadataReader.readFixed_2_30(),
 				];
 
-				const rotation = extractRotationFromMatrix(matrix);
+				const rotation = (roundToMultiple(extractRotationFromMatrix(matrix), 90) + 360) % 360 as Rotation;
-				const comparisonMatrix = rotationMatrix(rotation);
+				assert(rotation === 0 || rotation === 90 || rotation === 180 || rotation === 270);
 
-				const matrixIndex = knownMatrixes.findIndex(mat => mat.every((y, i) => y === comparisonMatrix[i]));
+				// Flip clockwise to counter-clockwise
-				if (matrixIndex === -1) {
+				track.rotation = (-rotation + 360) % 360 as Rotation;
-					console.warn(`Wacky rotation matrix ${comparisonMatrix.join(',')}; sticking with no rotation.`);
-					track.rotation = 0;
-				} else {
-					track.rotation = (90 * matrixIndex) as Rotation;
-				}
 			}; break;
 
 			case 'elst': {
@@ -739,6 +733,11 @@ export class IsobmffDemuxer extends Demuxer {
 						track.languageCode = String.fromCharCode(0x60 + (language & 0b11111)) + track.languageCode;
 						language >>= 5;
 					}
+
+					if (!isIso639Dash2LanguageCode(track.languageCode)) {
+						// Sometimes the bytes are garbage
+						track.languageCode = UNDETERMINED_LANGUAGE;
+					}
 				}
 			}; break;
 

src/isobmff/isobmff-muxer.ts

@@ -13,7 +13,7 @@ import {
 	validateSubtitleMetadata,
 	validateVideoChunkMetadata,
 } from '../codec';
-import { EncodedAudioSample, EncodedVideoSample } from '../sample';
+import { EncodedAudioSample, EncodedVideoSample, SampleType } from '../sample';
 import { BufferTarget } from '../target';
 
 export const GLOBAL_TIMESCALE = 1000;
@@ -25,7 +25,7 @@ export type Sample = {
 	duration: number;
 	data: Uint8Array | null;
 	size: number;
-	type: 'key' | 'delta';
+	type: SampleType;
 	timescaleUnitsToNextSample: number;
 };
 
@@ -492,7 +492,7 @@ export class IsobmffMuxer extends Muxer {
 		data: Uint8Array,
 		timestamp: number,
 		duration: number,
-		type: 'key' | 'delta',
+		type: SampleType,
 	) {
 		const sample: Sample = {
 			timestamp,
@@ -564,6 +564,8 @@ export class IsobmffMuxer extends Muxer {
 
 				const timescaleUnits = intoTimescale(sample.decodeTimestamp, trackData.timescale, false);
 				const delta = Math.round(timescaleUnits - trackData.lastTimescaleUnits);
+				assert(delta >= 0);
+
 				trackData.lastTimescaleUnits += delta;
 				trackData.lastSample.timescaleUnitsToNextSample = delta;
 

src/matroska/matroska-demuxer.ts

@@ -26,6 +26,7 @@ import {
 	binarySearchLessOrEqual,
 	COLOR_PRIMARIES_MAP_INVERSE,
 	findLastIndex,
+	isIso639Dash2LanguageCode,
 	last,
 	MATRIX_COEFFICIENTS_MAP_INVERSE,
 	Rotation,
@@ -749,6 +750,10 @@ export class MatroskaDemuxer extends Demuxer {
 				if (!this.currentTrack) break;
 
 				this.currentTrack.languageCode = reader.readString(size);
+
+				if (!isIso639Dash2LanguageCode(this.currentTrack.languageCode)) {
+					this.currentTrack.languageCode = UNDETERMINED_LANGUAGE;
+				}
 			}; break;
 
 			case EBMLId.Video: {

src/matroska/matroska-muxer.ts

@@ -687,8 +687,8 @@ export class MatroskaMuxer extends Muxer {
 		}
 
 		const relativeTimestamp = msTimestamp - this.currentClusterStartMsTimestamp!;
-		if (relativeTimestamp < 0) {
+		if (relativeTimestamp < -(2 ** 15)) {
-			// The chunk lies outside of the current cluster
+			// The block lies too far in the past, it's not representable within this cluster
 			return;
 		}
 

src/misc.ts

@@ -393,6 +393,10 @@ export const roundToPrecision = (value: number, digits: number) => {
 	return Math.round(value * factor) / factor;
 };
 
+export const roundToMultiple = (value: number, multiple: number) => {
+	return Math.round(value / multiple) * multiple;
+};
+
 export const ilog = (x: number) => {
 	let ret = 0;
 	while (x) {
@@ -401,3 +405,8 @@ export const ilog = (x: number) => {
 	}
 	return ret;
 };
+
+const ISO_639_2_REGEX = /^[a-z]{3}$/;
+export const isIso639Dash2LanguageCode = (x: string) => {
+	return ISO_639_2_REGEX.test(x);
+};

src/muxer.ts

@@ -31,7 +31,7 @@ export abstract class Muxer {
 	private trackTimestampInfo = new WeakMap<OutputTrack, {
 		timestampOffset: number;
 		maxTimestamp: number;
-		lastKeyFrameTimestamp: number;
+		maxTimestampBeforeLastKeyFrame: number;
 	}>();
 
 	protected validateAndNormalizeTimestamp(track: OutputTrack, timestampInSeconds: number, isKeyFrame: boolean) {
@@ -44,7 +44,7 @@ export abstract class Muxer {
 			timestampInfo = {
 				timestampOffset: timestampInSeconds,
 				maxTimestamp: track.source._offsetTimestamps ? 0 : timestampInSeconds,
-				lastKeyFrameTimestamp: track.source._offsetTimestamps ? 0 : timestampInSeconds,
+				maxTimestampBeforeLastKeyFrame: track.source._offsetTimestamps ? 0 : timestampInSeconds,
 			};
 			this.trackTimestampInfo.set(track, timestampInfo);
 		}
@@ -57,22 +57,16 @@ export abstract class Muxer {
 			throw new Error(`Timestamps must be non-negative (got ${timestampInSeconds}s).`);
 		}
 
-		if (timestampInSeconds < timestampInfo.lastKeyFrameTimestamp) {
+		if (isKeyFrame) {
-			throw new Error(
+			timestampInfo.maxTimestampBeforeLastKeyFrame = timestampInfo.maxTimestamp;
-				`Timestamp cannot be smaller than last key frame's timestamp (got ${timestampInSeconds}s,`
-				+ ` last key frame at ${timestampInfo.lastKeyFrameTimestamp}s).`,
-			);
 		}
 
-		if (isKeyFrame) {
+		if (timestampInSeconds < timestampInfo.maxTimestampBeforeLastKeyFrame) {
-			if (timestampInSeconds < timestampInfo.maxTimestamp) {
+			throw new Error(
-				throw new Error(
+				`Timestamps cannot be smaller than the highest timestamp of the previous run (a run begins with a`
-					`Key frame timestamps cannot be smaller than any timestamp that came before`
+				+ ` key frame and ends right before the next key frame). Got ${timestampInSeconds}s, but highest`
-					+ ` (got ${timestampInSeconds}s, max timestamp was ${timestampInfo.maxTimestamp}s).`,
+				+ ` timestamp is ${timestampInfo.maxTimestampBeforeLastKeyFrame}s.`,
-				);
+			);
-			}
-
-			timestampInfo.lastKeyFrameTimestamp = timestampInSeconds;
 		}
 
 		timestampInfo.maxTimestamp = Math.max(timestampInfo.maxTimestamp, timestampInSeconds);

src/output.ts

@@ -1,4 +1,4 @@
-import { AsyncMutex, TransformationMatrix } from './misc';
+import { AsyncMutex, isIso639Dash2LanguageCode, TransformationMatrix } from './misc';
 import { Muxer } from './muxer';
 import { OutputFormat } from './output-format';
 import { AudioSource, MediaSource, SubtitleSource, VideoSource } from './media-source';
@@ -60,7 +60,7 @@ const validateBaseTrackMetadata = (metadata: BaseTrackMetadata) => {
 	if (!metadata || typeof metadata !== 'object') {
 		throw new TypeError('metadata must be an object.');
 	}
-	if (metadata.languageCode !== undefined && !/^[a-z]{3}$/.test(metadata.languageCode)) {
+	if (metadata.languageCode !== undefined && !isIso639Dash2LanguageCode(metadata.languageCode)) {
 		throw new TypeError('metadata.languageCode must be a three-letter, ISO 639-2 language code.');
 	}
 };

todo.txt

@@ -1,3 +1,5 @@
 - onHeader, etc callbacks for Matroska
 - https://github.com/Vanilagy/mp4-muxer/issues/83 tell him it's possible now
 - is this fixed? https://github.com/Vanilagy/webm-muxer/issues/50
+- cross-track offset for streaming sources
+- configurable fragmented mp4 fragment size, like the mp4-muxer PR