Bump-patch

* implement in FlacOutputFormatOptions

* implement in flac-muxer.ts

* Fix demuxer: Handle minimumFrameSize = 0, maxiumFrameSize = 0

* add a test

* Update flac-demuxer.ts

* Update flac.test.ts

* clean up comments for minima and maxima

* Add FlacOutputFormatOptions.appendOnly to docs

---------

Co-authored-by: Vanilagy <[email protected]>

dev/convert.html

@@ -104,6 +104,8 @@
 			},
 			*/
 			video: () => ({
+				//width: 640,
+				//rotate: 90,
 				//forceTranscode: true,
 				//forceTranscode: true,
 				//width: 1280,
@@ -189,7 +191,7 @@
 			},
 			trim: {
 				//start: 0,
-				//end: 10
+				end: 2
 			},
 		});
 		console.log(conversion);

dev/demux.html

@@ -21,7 +21,11 @@
 		const sink = new Mediabunny.EncodedPacketSink(videoTrack);
 
 		for await (const packet of sink.packets()) {
-			console.log(packet.timestamp);
+			console.log(packet.type, packet.timestamp);
+
+			if (packet.timestamp >= 5) {
+				break;
+			}
 		}
 
 		/*

docs/guide/output-formats.md

@@ -303,9 +303,16 @@ const output = new Output({
 The following options are available:
 ```ts
 type FlacOutputFormatOptions = {
+	appendOnly?: boolean;
+
 	onFrame?: (data: Uint8Array, position: number) => unknown;
 };
 ```
+- `appendOnly`\
+	Configures the output to only append new data at the end, useful for live-streaming the file as it's being created. When enabled, the STREAMINFO block will not be finalized with accurate min/max block sizes, frame sizes, or total sample count, so don't use this option when you want to write out a clean file for later use.
+	::: info
+	This option ensures [append-only writing](#append-only-writing).
+	:::
 - `onFrame`\
 	Will be called for each FLAC frame that is written.
 

docs/index.md

@@ -109,9 +109,11 @@ const sponsors = {
 	],
 	individual: [
 		{ image: '/sponsors/pintura-labs.png', name: 'Pintura Labs', url: 'https://pqina.nl/pintura/' },
+		{ image: 'https://avatars.githubusercontent.com/u/11537072', name: 'Threema', url: 'https://threema.com/en' },
 		{ image: 'https://avatars.githubusercontent.com/u/82552321', name: 'Polotno', url: 'https://github.com/polotno-project' },
 		{ image: 'https://avatars.githubusercontent.com/u/489051', name: 'Roman Rädle', url: 'https://github.com/raedle' },
 		{ image: 'https://avatars.githubusercontent.com/u/197597', name: 'Christopher Chedeau', url: 'https://github.com/vjeux' },
+		{ image: 'https://avatars.githubusercontent.com/u/18653821', name: 'ZerGo0', url: 'https://github.com/ZerGo0' },
 		{ image: 'https://avatars.githubusercontent.com/u/5913254', name: 'Brandon McConnell', url: 'https://github.com/brandonmcconnell' },
 		{ image: 'https://avatars.githubusercontent.com/u/9549394', name: 'studnitz', url: 'https://github.com/studnitz' },
 		{ image: 'https://avatars.githubusercontent.com/u/4714175', name: 'Phoomparin Mano', url: 'https://github.com/heypoom' },
@@ -119,6 +121,7 @@ const sponsors = {
 		{ image: 'https://avatars.githubusercontent.com/u/2698271', name: 'Matthew Gardner', url: 'https://github.com/spheric' },
 		{ image: 'https://avatars.githubusercontent.com/u/5475819', name: 'AJ Funk', url: 'https://github.com/AJFunk' },
 		{ image: 'https://avatars.githubusercontent.com/u/30229596', name: 'Pablo Bonilla', url: 'https://github.com/devPablo' },
+		{ image: 'https://avatars.githubusercontent.com/u/536008', name: 'Satish Goda', url: 'https://github.com/satishgoda' },
 		{ image: 'https://avatars.githubusercontent.com/u/139718', name: 'Anton Kosiakin', url: 'https://github.com/deil' },
 		{ image: 'https://avatars.githubusercontent.com/u/56988069', name: 'SyhabouthAlex', url: 'https://github.com/SyhabouthAlex' },
 		{ image: 'https://avatars.githubusercontent.com/u/38181164', name: 'wcw', url: 'https://github.com/asd55667' },
@@ -135,6 +138,7 @@ const sponsors = {
 		{ image: 'https://avatars.githubusercontent.com/u/31102694', name: 'Aiden Liu', url: 'https://github.com/aidenlx' },
 		{ image: 'https://avatars.githubusercontent.com/u/41021374', name: 'arthco', url: 'https://github.com/arthtyagi' },
 		{ image: 'https://avatars.githubusercontent.com/u/5907357', name: 'Harvey Zhao', url: 'https://github.com/zhw2590582' },
+		{ image: 'https://avatars.githubusercontent.com/u/13042781?v=4', name: 'Anshul Bansal', url: 'https://github.com/akbansa' },
 	],
 };
 </script>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mediabunny",
-  "version": "1.39.1",
+  "version": "1.40.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mediabunny",
-      "version": "1.39.1",
+      "version": "1.40.1",
       "license": "MPL-2.0",
       "workspaces": [
         "packages/*"
@@ -7751,9 +7751,9 @@
       }
     },
     "node_modules/mediabunny": {
-      "version": "1.39.0",
-      "resolved": "https://registry.npmjs.org/mediabunny/-/mediabunny-1.39.0.tgz",
-      "integrity": "sha512-NDeht2Sf7kYfrUu7b/9AhVK4KdQhy6UeTF/EPNXW+PdpIYvSv36ZQ/SRBoFAJN2LRl6XrGb8JYY4MCnhsGQ2yg==",
+      "version": "1.40.0",
+      "resolved": "https://registry.npmjs.org/mediabunny/-/mediabunny-1.40.0.tgz",
+      "integrity": "sha512-UztWnjkA15yYxqq7AC8MSsU4U6FIFIBHvHV94pouvjxQa0y2pGvi1HPmrFcaYrRZAuSKTrdw45VXUIe3gEEpsA==",
       "license": "MPL-2.0",
       "peer": true,
       "workspaces": [
@@ -12077,7 +12077,7 @@
     },
     "packages/aac-encoder": {
       "name": "@mediabunny/aac-encoder",
-      "version": "1.39.1",
+      "version": "1.40.1",
       "license": "MPL-2.0",
       "devDependencies": {
         "@types/emscripten": "^1.40.1"
@@ -12092,7 +12092,7 @@
     },
     "packages/ac3": {
       "name": "@mediabunny/ac3",
-      "version": "1.39.1",
+      "version": "1.40.1",
       "license": "MPL-2.0",
       "devDependencies": {
         "@types/emscripten": "^1.40.1"
@@ -12107,7 +12107,7 @@
     },
     "packages/flac-encoder": {
       "name": "@mediabunny/flac-encoder",
-      "version": "1.39.1",
+      "version": "1.40.1",
       "license": "MPL-2.0",
       "devDependencies": {
         "@types/emscripten": "^1.40.1"
@@ -12122,7 +12122,7 @@
     },
     "packages/mp3-encoder": {
       "name": "@mediabunny/mp3-encoder",
-      "version": "1.39.1",
+      "version": "1.40.1",
       "license": "MPL-2.0",
       "devDependencies": {
         "@types/emscripten": "^1.40.1"

package.json

@@ -1,7 +1,7 @@
 {
   "name": "mediabunny",
   "author": "Vanilagy",
-  "version": "1.39.1",
+  "version": "1.40.1",
   "description": "Pure TypeScript media toolkit for reading, writing, and converting media files, directly in the browser.",
   "type": "module",
   "workspaces": [

packages/aac-encoder/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@mediabunny/aac-encoder",
   "author": "Vanilagy",
-  "version": "1.39.1",
+  "version": "1.40.1",
   "description": "AAC encoder extension for Mediabunny, based on FFmpeg.",
   "main": "./dist/bundles/mediabunny-aac-encoder.mjs",
   "module": "./dist/bundles/mediabunny-aac-encoder.mjs",

packages/ac3/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@mediabunny/ac3",
   "author": "Vanilagy",
-  "version": "1.39.1",
+  "version": "1.40.1",
   "description": "AC-3 and E-AC-3 (Dolby Digital) decoder and encoder extension for Mediabunny, based on FFmpeg.",
   "main": "./dist/bundles/mediabunny-ac3.mjs",
   "module": "./dist/bundles/mediabunny-ac3.mjs",

packages/flac-encoder/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@mediabunny/flac-encoder",
   "author": "Vanilagy",
-  "version": "1.39.1",
+  "version": "1.40.1",
   "description": "FLAC encoder extension for Mediabunny, based on libFLAC.",
   "main": "./dist/bundles/mediabunny-flac-encoder.mjs",
   "module": "./dist/bundles/mediabunny-flac-encoder.mjs",

packages/mp3-encoder/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@mediabunny/mp3-encoder",
   "author": "Vanilagy",
-  "version": "1.39.1",
+  "version": "1.40.1",
   "description": "MP3 encoder extension for Mediabunny, based on LAME.",
   "main": "./dist/bundles/mediabunny-mp3-encoder.mjs",
   "module": "./dist/bundles/mediabunny-mp3-encoder.mjs",

src/conversion.ts

@@ -1086,6 +1086,8 @@ export class Conversion {
 			}
 
 			if (needsRerender) {
+				outputTrackRotation = 0; // Since the rotation is baked into the output
+
 				this._trackPromises.push((async () => {
 					await this._started;
 
@@ -1101,8 +1103,6 @@ export class Conversion {
 					const iterator = sink.canvases(this._startTimestamp, this._endTimestamp);
 					const frameRate = trackOptions.frameRate;
 
-					outputTrackRotation = 0; // Since the rotation is baked into the output
-
 					let lastCanvas: HTMLCanvasElement | OffscreenCanvas | null = null;
 					let lastCanvasTimestamp: number | null = null;
 					let lastCanvasEndTimestamp: number | null = null;

src/flac/flac-demuxer.ts

@@ -283,13 +283,38 @@ export class FlacDemuxer extends Demuxer {
 		// --> 6 bytes
 		const minimumHeaderLength = 6;
 		// If we read everything in readFlacFrameHeader, we read 16 bytes
-		const maximumHeaderSize = 16;
+		const maximumHeaderLength = 16;
+
+		// The shortest valid FLAC frame per RFC 9639:
+		// 6 bytes header (see minimumHeaderLength above)
+		// 2 bytes subframe (constant subframe with minimum bit depth,
+		//   padded to byte boundary)
+		// 2 bytes footer (CRC-16)
+		// --> 10 bytes
+		const minimumFrameLength = 10;
+
+		// The longest valid FLAC frame per RFC 9639:
+		// https://www.rfc-editor.org/rfc/rfc9639.html#name-prediction
+		// https://www.rfc-editor.org/rfc/rfc9639.html#name-frame-structure
+		// maximumBlockSize * numberOfChannels * 4 bytes (max 32 bps verbatim)
+		// + 16 bytes header (see maximumHeaderSize above)
+		// + 2 bytes footer (CRC-16)
+		const maximumFrameLength = this.audioInfo.maximumBlockSize
+			* this.audioInfo.numberOfChannels
+			* 4
+			+ maximumHeaderLength
+			+ 2;
+
+		// Per RFC 9639, a value of 0 means "unknown" for frame sizes.
+		const effectiveMinFrameSize = this.audioInfo.minimumFrameSize || minimumFrameLength;
+		const effectiveMaxFrameSize = this.audioInfo.maximumFrameSize || maximumFrameLength;
+
 		const maximumSliceLength
-			= this.audioInfo.maximumFrameSize + maximumHeaderSize;
+			= effectiveMaxFrameSize + maximumHeaderLength;
 
 		const slice = await this.reader.requestSliceRange(
 			startPos,
-			this.audioInfo.minimumFrameSize,
+			maximumHeaderLength,
 			maximumSliceLength,
 		);
 
@@ -312,7 +337,7 @@ export class FlacDemuxer extends Demuxer {
 
 		// The next sync word is expected at earliest when `minimumFrameSize` is reached,
 		// we can skip over anything before that
-		slice.filePos = startPos + this.audioInfo.minimumFrameSize;
+		slice.filePos = startPos + effectiveMinFrameSize;
 
 		while (true) {
 			// Reached end of the file, packet is over

src/flac/flac-muxer.ts

@@ -50,6 +50,10 @@ export class FlacMuxer extends Muxer {
 
 		this.writer = output._writer;
 		this.format = format;
+
+		if (this.format._options.appendOnly) {
+			this.writer.ensureMonotonicity = true;
+		}
 	}
 
 	async start() {
@@ -165,7 +169,9 @@ export class FlacMuxer extends Muxer {
 	}
 
 	writeVorbisCommentAndPictureBlock() {
-		this.writer.seek(STREAMINFO_SIZE + FLAC_HEADER.byteLength);
+		if (!this.format._options.appendOnly) {
+			this.writer.seek(STREAMINFO_SIZE + FLAC_HEADER.byteLength);
+		}
 		if (metadataTagsAreEmpty(this.output._metadataTags)) {
 			this.metadataWritten = true;
 			return;
@@ -233,6 +239,30 @@ export class FlacMuxer extends Muxer {
 				descriptionBitstream.skipBits(103 + 64);
 				const bitsPerSample = descriptionBitstream.readBits(5) + 1;
 				this.bitsPerSample = bitsPerSample;
+
+				if (this.format._options.appendOnly) {
+					// Write STREAMINFO immediately since we can't seek back later.
+					this.writeHeader({
+						// https://www.rfc-editor.org/rfc/rfc9639.html#name-streaminfo
+						// Per RFC 9639, min/max block sizes can be looser than
+						// actual values, so we use the full valid range (16–65535).
+						// "The actual max block size MAY be smaller than what's
+						// listed, and the actual min (excluding last block) MAY be
+						// larger. This is because the encoder has to write these
+						// fields before receiving any input audio data and cannot
+						// know beforehand what block sizes it will use."
+						minimumBlockSize: 16,
+						maximumBlockSize: 65535,
+						// https://www.rfc-editor.org/rfc/rfc9639.html#name-streaminfo
+						// "A value of 0 signifies that the value is not known."
+						minimumFrameSize: 0,
+						maximumFrameSize: 0,
+						sampleRate: this.sampleRate,
+						channels: this.channels,
+						bitsPerSample: this.bitsPerSample,
+						totalSamples: 0,
+					});
+				}
 			}
 
 			if (!this.metadataWritten) {
@@ -251,8 +281,10 @@ export class FlacMuxer extends Muxer {
 			readCodedNumber(slice); // num
 			const blockSize = readBlockSize(slice, blockSizeOrUncommon);
 
-			this.blockSizes.push(blockSize);
-			this.frameSizes.push(packet.data.length);
+			if (!this.format._options.appendOnly) {
+				this.blockSizes.push(blockSize);
+				this.frameSizes.push(packet.data.length);
+			}
 
 			const startPos = this.writer.getPos();
 			this.writer.write(packet.data);
@@ -274,43 +306,45 @@ export class FlacMuxer extends Muxer {
 	async finalize(): Promise<void> {
 		const release = await this.mutex.acquire();
 
-		let minimumBlockSize = Infinity;
-		let maximumBlockSize = 0;
-		let minimumFrameSize = Infinity;
-		let maximumFrameSize = 0;
-		let totalSamples = 0;
-		for (let i = 0; i < this.blockSizes.length; i++) {
-			minimumFrameSize = Math.min(minimumFrameSize, this.frameSizes[i]!);
-			maximumFrameSize = Math.max(maximumFrameSize, this.frameSizes[i]!);
-			maximumBlockSize = Math.max(maximumBlockSize, this.blockSizes[i]!);
-			totalSamples += this.blockSizes[i]!;
+		if (!this.format._options.appendOnly) {
+			let minimumBlockSize = Infinity;
+			let maximumBlockSize = 0;
+			let minimumFrameSize = Infinity;
+			let maximumFrameSize = 0;
+			let totalSamples = 0;
+			for (let i = 0; i < this.blockSizes.length; i++) {
+				minimumFrameSize = Math.min(minimumFrameSize, this.frameSizes[i]!);
+				maximumFrameSize = Math.max(maximumFrameSize, this.frameSizes[i]!);
+				maximumBlockSize = Math.max(maximumBlockSize, this.blockSizes[i]!);
+				totalSamples += this.blockSizes[i]!;
 
-			// Excluding the last frame from block size calculation
-			// https://www.rfc-editor.org/rfc/rfc9639.html#name-streaminfo
-			// "The minimum block size (in samples) used in the stream, excluding the last block."
-			const isLastFrame = i === this.blockSizes.length - 1;
-			if (isLastFrame) {
-				continue;
+				// Excluding the last frame from block size calculation
+				// https://www.rfc-editor.org/rfc/rfc9639.html#name-streaminfo
+				// "The minimum block size (in samples) used in the stream, excluding the last block."
+				const isLastFrame = i === this.blockSizes.length - 1;
+				if (isLastFrame) {
+					continue;
+				}
+				minimumBlockSize = Math.min(minimumBlockSize, this.blockSizes[i]!);
 			}
-			minimumBlockSize = Math.min(minimumBlockSize, this.blockSizes[i]!);
+
+			assert(this.sampleRate !== null);
+			assert(this.channels !== null);
+			assert(this.bitsPerSample !== null);
+
+			this.writer.seek(4);
+			this.writeHeader({
+				minimumBlockSize,
+				maximumBlockSize,
+				minimumFrameSize,
+				maximumFrameSize,
+				sampleRate: this.sampleRate,
+				channels: this.channels,
+				bitsPerSample: this.bitsPerSample,
+				totalSamples,
+			});
 		}
 
-		assert(this.sampleRate !== null);
-		assert(this.channels !== null);
-		assert(this.bitsPerSample !== null);
-
-		this.writer.seek(4);
-		this.writeHeader({
-			minimumBlockSize,
-			maximumBlockSize,
-			minimumFrameSize,
-			maximumFrameSize,
-			sampleRate: this.sampleRate,
-			channels: this.channels,
-			bitsPerSample: this.bitsPerSample,
-			totalSamples,
-		});
-
 		release();
 	}
 }

src/input-format.ts

@@ -530,7 +530,7 @@ export class MpegTsInputFormat extends InputFormat {
 		} else if (bytes[0] === 0x47 && bytes[TS_PACKET_SIZE + 16] === 0x47) {
 			// MPEG-TS with Forward Error Correction
 			return true;
-		} else if (bytes[4] === 0x47 && bytes[4 + TS_PACKET_SIZE] === 0x47) {
+		} else if (bytes[4] === 0x47 && bytes[4 + TS_PACKET_SIZE + 4] === 0x47) {
 			// MPEG-2-TS (DVHS)
 			return true;
 		}

src/isobmff/isobmff-demuxer.ts

@@ -2947,15 +2947,23 @@ class IsobmffVideoTrackBacking extends IsobmffTrackBacking implements InputVideo
 				this.internalTrack.info.av1CodecInfo = firstPacket && extractAv1CodecInfoFromPacket(firstPacket.data);
 			}
 
-			return {
+			const config: VideoDecoderConfig = {
 				codec: extractVideoCodecString(this.internalTrack.info),
 				codedWidth: this.internalTrack.info.width,
 				codedHeight: this.internalTrack.info.height,
-				displayAspectWidth: this.internalTrack.info.squarePixelWidth,
-				displayAspectHeight: this.internalTrack.info.squarePixelHeight,
 				description: this.internalTrack.info.codecDescription ?? undefined,
 				colorSpace: this.internalTrack.info.colorSpace ?? undefined,
 			};
+
+			if (
+				this.internalTrack.info.width !== this.internalTrack.info.squarePixelWidth
+				|| this.internalTrack.info.height !== this.internalTrack.info.squarePixelHeight
+			) {
+				config.displayAspectWidth = this.internalTrack.info.squarePixelWidth;
+				config.displayAspectHeight = this.internalTrack.info.squarePixelHeight;
+			}
+
+			return config;
 		})();
 	}
 }
@@ -3169,22 +3177,16 @@ const offsetFragmentTrackDataByTimestamp = (trackData: FragmentTrackData, timest
 
 /** Extracts the rotation component from a transformation matrix, in degrees. */
 const extractRotationFromMatrix = (matrix: TransformationMatrix) => {
-	const [m11, , , m21] = matrix;
+	const [a, b] = matrix; // (1, 0) projects onto (a, b), so that's all we need
 
-	const scaleX = Math.hypot(m11, m21);
+	const radians = Math.atan2(b, a);
 
-	const cosTheta = m11 / scaleX;
-	const sinTheta = m21 / scaleX;
-
-	// Invert the rotation because matrices are post-multiplied in ISOBMFF
-	const result = -Math.atan2(sinTheta, cosTheta) * (180 / Math.PI);
-
-	if (!Number.isFinite(result)) {
+	if (!Number.isFinite(radians)) {
 		// Can happen if the entire matrix is 0, for example
 		return 0;
 	}
 
-	return result;
+	return radians * (180 / Math.PI);
 };
 
 const sampleTableIsEmpty = (sampleTable: SampleTable) => {

src/matroska/matroska-demuxer.ts

@@ -196,6 +196,7 @@ type InternalTrack = {
 	defaultDurationNs: number | null;
 	name: string | null;
 	languageCode: string;
+	hasLanguageBcp47: boolean;
 	decodingInstructions: DecodingInstruction[];
 
 	info:
@@ -1009,7 +1010,8 @@ export class MatroskaDemuxer extends Demuxer {
 					defaultDuration: null,
 					defaultDurationNs: null,
 					name: null,
-					languageCode: UNDETERMINED_LANGUAGE,
+					languageCode: 'eng', // The default in Matroska
+					hasLanguageBcp47: false,
 					decodingInstructions: [],
 
 					info: null,
@@ -1086,11 +1088,7 @@ export class MatroskaDemuxer extends Demuxer {
 						const inputTrack = new InputVideoTrack(this.input, new MatroskaVideoTrackBacking(videoTrack));
 						this.currentTrack.inputTrack = inputTrack;
 						this.currentSegment.tracks.push(this.currentTrack);
-					} else if (
-						this.currentTrack.info.type === 'audio'
-						&& this.currentTrack.info.numberOfChannels !== -1
-						&& this.currentTrack.info.sampleRate !== -1
-					) {
+					} else if (this.currentTrack.info.type === 'audio') {
 						if (codecIdWithoutSuffix === CODEC_STRING_MAP.aac) {
 							this.currentTrack.info.codec = 'aac';
 							this.currentTrack.info.aacCodecInfo = {
@@ -1183,8 +1181,8 @@ export class MatroskaDemuxer extends Demuxer {
 				} else if (type === 2) {
 					this.currentTrack.info = {
 						type: 'audio',
-						numberOfChannels: -1,
-						sampleRate: -1,
+						numberOfChannels: 1, // Default value
+						sampleRate: 8000, // Default value
 						bitDepth: -1,
 						codec: null,
 						codecDescription: null,
@@ -1263,7 +1261,7 @@ export class MatroskaDemuxer extends Demuxer {
 
 			case EBMLId.Language: {
 				if (!this.currentTrack) break;
-				if (this.currentTrack.languageCode !== UNDETERMINED_LANGUAGE) {
+				if (this.currentTrack.hasLanguageBcp47) {
 					// LanguageBCP47 was present, which takes precedence
 					break;
 				}
@@ -1290,6 +1288,8 @@ export class MatroskaDemuxer extends Demuxer {
 				} else {
 					this.currentTrack.languageCode = UNDETERMINED_LANGUAGE;
 				}
+
+				this.currentTrack.hasLanguageBcp47 = true;
 			}; break;
 
 			case EBMLId.Video: {
@@ -2430,7 +2430,7 @@ class MatroskaVideoTrackBacking extends MatroskaTrackBacking implements InputVid
 				firstPacket = await this.getFirstPacket({});
 			}
 
-			return {
+			const config: VideoDecoderConfig = {
 				codec: extractVideoCodecString({
 					width: this.internalTrack.info.width,
 					height: this.internalTrack.info.height,
@@ -2453,11 +2453,19 @@ class MatroskaVideoTrackBacking extends MatroskaTrackBacking implements InputVid
 				}),
 				codedWidth: this.internalTrack.info.width,
 				codedHeight: this.internalTrack.info.height,
-				displayAspectWidth: this.internalTrack.info.squarePixelWidth,
-				displayAspectHeight: this.internalTrack.info.squarePixelHeight,
 				description: this.internalTrack.info.codecDescription ?? undefined,
 				colorSpace: this.internalTrack.info.colorSpace ?? undefined,
 			};
+
+			if (
+				this.internalTrack.info.width !== this.internalTrack.info.squarePixelWidth
+				|| this.internalTrack.info.height !== this.internalTrack.info.squarePixelHeight
+			) {
+				config.displayAspectWidth = this.internalTrack.info.squarePixelWidth;
+				config.displayAspectHeight = this.internalTrack.info.squarePixelHeight;
+			}
+
+			return config;
 		})();
 	}
 }

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

@@ -161,10 +161,10 @@ export class MpegTsDemuxer extends Demuxer {
 				// MPEG-TS with Forward Error Correction
 				this.packetOffset = 0;
 				this.packetStride = TS_PACKET_SIZE + 16;
-			} else if (startingBytes[4] === 0x47 && startingBytes[4 + TS_PACKET_SIZE] === 0x47) {
+			} else if (startingBytes[4] === 0x47 && startingBytes[4 + TS_PACKET_SIZE + 4] === 0x47) {
 				// MPEG-2-TS (DVHS)
 				this.packetOffset = 4;
-				this.packetStride = TS_PACKET_SIZE;
+				this.packetStride = TS_PACKET_SIZE + 4;
 			} else {
 				throw new Error('Unreachable.');
 			}
@@ -236,12 +236,13 @@ export class MpegTsDemuxer extends Demuxer {
 					while (8 * (sectionLength + BYTES_BEFORE_SECTION_LENGTH) - bitstream.pos > BITS_IN_CRC_32) {
 						const programNumber = bitstream.readBits(16);
 						bitstream.skipBits(3); // Reserved
+						const id = bitstream.readBits(13);
 
 						if (programNumber !== 0) {
 							if (programMapPid !== null) {
 								throw new Error('Only files with a single program are supported.');
 							} else {
-								programMapPid = bitstream.readBits(13);
+								programMapPid = id;
 							}
 						}
 					}
@@ -1031,8 +1032,6 @@ export abstract class MpegTsTrackBacking implements InputTrackBacking {
 			return null;
 		}
 
-		// result.packet.randomAccessIndicator = 1; // Assume the first packet is always a key packet
-
 		const packet = this.createEncodedPacket(result.packet, result.duration, options);
 		this.packetBuffers.set(packet, buffer);
 		this.packetSectionStarts.set(packet, result.packet.sectionStartPos);
@@ -1514,10 +1513,16 @@ class MpegTsVideoTrackBacking extends MpegTsTrackBacking implements InputVideoTr
 			}),
 			codedWidth: this.elementaryStream.info.width,
 			codedHeight: this.elementaryStream.info.height,
-			displayAspectWidth: this.elementaryStream.info.squarePixelWidth,
-			displayAspectHeight: this.elementaryStream.info.squarePixelHeight,
 			colorSpace: this.elementaryStream.info.colorSpace,
 		};
+
+		if (
+			this.elementaryStream.info.width !== this.elementaryStream.info.squarePixelWidth
+			|| this.elementaryStream.info.height !== this.elementaryStream.info.squarePixelHeight
+		) {
+			this.decoderConfig.displayAspectWidth = this.elementaryStream.info.squarePixelWidth;
+			this.decoderConfig.displayAspectHeight = this.elementaryStream.info.squarePixelHeight;
+		}
 	}
 
 	override getCodec(): VideoCodec {

src/muxer.ts

@@ -46,12 +46,16 @@ export abstract class Muxer {
 
 	private trackTimestampInfo = new WeakMap<OutputTrack, {
 		maxTimestamp: number;
-		maxTimestampBeforeLastKeyPacket: number;
+		maxTimestampBeforeLastKeyPacket: number | null;
 	}>();
 
 	protected validateAndNormalizeTimestamp(track: OutputTrack, timestampInSeconds: number, isKeyPacket: boolean) {
 		timestampInSeconds += track.source._timestampOffset;
 
+		if (timestampInSeconds < 0) {
+			throw new Error(`Timestamps must be non-negative (got ${timestampInSeconds}s).`);
+		}
+
 		let timestampInfo = this.trackTimestampInfo.get(track);
 		if (!timestampInfo) {
 			if (!isKeyPacket) {
@@ -60,29 +64,28 @@ export abstract class Muxer {
 
 			timestampInfo = {
 				maxTimestamp: timestampInSeconds,
-				maxTimestampBeforeLastKeyPacket: timestampInSeconds,
+				maxTimestampBeforeLastKeyPacket: null,
 			};
 			this.trackTimestampInfo.set(track, timestampInfo);
-		}
+		} else {
+			if (isKeyPacket) {
+				timestampInfo.maxTimestampBeforeLastKeyPacket = timestampInfo.maxTimestamp;
+			}
 
-		if (timestampInSeconds < 0) {
-			throw new Error(`Timestamps must be non-negative (got ${timestampInSeconds}s).`);
-		}
+			if (
+				timestampInfo.maxTimestampBeforeLastKeyPacket !== null
+				&& timestampInSeconds < timestampInfo.maxTimestampBeforeLastKeyPacket
+			) {
+				throw new Error(
+					`Timestamps cannot be smaller than the largest timestamp of the previous GOP (a GOP begins with a`
+					+ ` key packet and ends right before the next key packet). Got ${timestampInSeconds}s, but largest`
+					+ ` timestamp is ${timestampInfo.maxTimestampBeforeLastKeyPacket}s.`,
+				);
+			}
 
-		if (isKeyPacket) {
-			timestampInfo.maxTimestampBeforeLastKeyPacket = timestampInfo.maxTimestamp;
+			timestampInfo.maxTimestamp = Math.max(timestampInfo.maxTimestamp, timestampInSeconds);
 		}
 
-		if (timestampInSeconds < timestampInfo.maxTimestampBeforeLastKeyPacket) {
-			throw new Error(
-				`Timestamps cannot be smaller than the largest timestamp of the previous GOP (a GOP begins with a key`
-				+ ` packet and ends right before the next key packet). Got ${timestampInSeconds}s, but largest`
-				+ ` timestamp is ${timestampInfo.maxTimestampBeforeLastKeyPacket}s.`,
-			);
-		}
-
-		timestampInfo.maxTimestamp = Math.max(timestampInfo.maxTimestamp, timestampInSeconds);
-
 		return timestampInSeconds;
 	}
 }

src/output-format.ts

@@ -928,6 +928,13 @@ export class AdtsOutputFormat extends OutputFormat {
  * @public
  */
 export type FlacOutputFormatOptions = {
+	/**
+	 * Configures the output to only append new data at the end, useful for live-streaming the file as it's being
+	 * created. When enabled, the STREAMINFO block will not be finalized with accurate min/max block sizes, frame sizes,
+	 * or total sample count, so don't use this option when you want to write out a clean file for later use.
+	 */
+	appendOnly?: boolean;
+
 	/**
 	 * Will be called for each FLAC frame that is written.
 	 *
@@ -951,6 +958,9 @@ export class FlacOutputFormat extends OutputFormat {
 		if (!options || typeof options !== 'object') {
 			throw new TypeError('options must be an object.');
 		}
+		if (options.appendOnly !== undefined && typeof options.appendOnly !== 'boolean') {
+			throw new TypeError('options.appendOnly, when provided, must be a boolean.');
+		}
 
 		super();
 

test/browser/conversion.test.ts

@@ -0,0 +1,49 @@
+import { ALL_FORMATS } from '../../src/input-format.js';
+import { Input } from '../../src/input.js';
+import { Mp4OutputFormat } from '../../src/output-format.js';
+import { Output } from '../../src/output.js';
+import { BufferSource, UrlSource } from '../../src/source.js';
+import { expect, test } from 'vitest';
+import { BufferTarget } from '../../src/target.js';
+import { Conversion } from '../../src/conversion.js';
+import { assert } from '../../src/misc.js';
+
+test('Rotation is baked-in when rerendering', async () => {
+	using input = new Input({
+		source: new UrlSource('/rotate-buck-bunny.mp4'),
+		formats: ALL_FORMATS,
+	});
+
+	const ogTrack = await input.getPrimaryVideoTrack();
+	assert(ogTrack);
+
+	expect(ogTrack.rotation).toBe(90);
+	expect(ogTrack.codedWidth).toBe(1920);
+	expect(ogTrack.codedHeight).toBe(1080);
+	expect(ogTrack.displayWidth).toBe(1080);
+	expect(ogTrack.displayHeight).toBe(1920);
+
+	const output = new Output({
+		format: new Mp4OutputFormat(),
+		target: new BufferTarget(),
+	});
+
+	const conversion = await Conversion.init({ input, output, video: {
+		width: 320,
+	} });
+	await conversion.execute();
+
+	using newInput = new Input({
+		source: new BufferSource(output.target.buffer!),
+		formats: ALL_FORMATS,
+	});
+
+	const track = await newInput.getPrimaryVideoTrack();
+	assert(track);
+
+	expect(track.codedWidth).toBe(320);
+	expect(track.codedHeight).toBe(570);
+	expect(track.displayWidth).toBe(320);
+	expect(track.displayHeight).toBe(570);
+	expect(track.rotation).toBe(0);
+});

test/browser/par.test.ts

@@ -87,8 +87,8 @@ test('Pixel aspect ratio transcode conversion', async () => {
 	expect(mp4.snapshot.squarePixelHeight).toBe(mp4.snapshot.codedHeight);
 	expect(mp4.snapshot.displayWidth).toBe(mp4.snapshot.codedWidth);
 	expect(mp4.snapshot.displayHeight).toBe(mp4.snapshot.codedHeight);
-	expect(mp4.snapshot.decoderDisplayAspectWidth).toBe(mp4.snapshot.codedWidth);
-	expect(mp4.snapshot.decoderDisplayAspectHeight).toBe(mp4.snapshot.codedHeight);
+	expect(mp4.snapshot.decoderDisplayAspectWidth).toBeUndefined();
+	expect(mp4.snapshot.decoderDisplayAspectHeight).toBeUndefined();
 
 	expect(mp4.snapshot.codedWidth).toBe(source.squarePixelWidth);
 	expect(mp4.snapshot.codedHeight).toBe(source.squarePixelHeight);

test/node/flac.test.ts

@@ -254,3 +254,33 @@ test('can re-mux a .flac', async () => {
 
 	expect(otherInputDecoderConfig).toEqual(otherOutputDecoderConfig);
 });
+
+test('appendOnly writes correct STREAMINFO header', async () => {
+	const filePath = path.join(__dirname, '..', 'public/sample.flac');
+	using input = new Input({
+		source: new FilePathSource(filePath),
+		formats: ALL_FORMATS,
+	});
+
+	const target = new BufferTarget();
+	const output = new Output({
+		format: new FlacOutputFormat({ appendOnly: true }),
+		target,
+	});
+
+	const conversion = await Conversion.init({ input, output });
+	await conversion.execute();
+
+	assert(target.buffer);
+	const bytes = new Uint8Array(target.buffer);
+
+	// STREAMINFO: min_block=16, max_block=65535, min_frame=0, max_frame=0
+	expect(bytes.slice(8, 18)).toEqual(new Uint8Array([
+		// minimum_block_size=16
+		0x00, 0x10,
+		// maximum_block_size=65535
+		0xFF, 0xFF,
+		// minimum_frame_size=0
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	]));
+});

test/node/mpeg-ts-demuxing.test.ts

@@ -46,8 +46,6 @@ test('MPEG-TS metadata reading', async () => {
 		codec: 'avc1.640020',
 		codedWidth: 720,
 		codedHeight: 720,
-		displayAspectWidth: 720,
-		displayAspectHeight: 720,
 		colorSpace: {
 			primaries: 'bt2020',
 			transfer: 'hlg',
@@ -561,8 +559,6 @@ test('MPEG-TS with HEVC video', async () => {
 		codec: 'hev1.1.6.L120.90',
 		codedWidth: 1920,
 		codedHeight: 1080,
-		displayAspectWidth: 1920,
-		displayAspectHeight: 1080,
 		colorSpace: {
 			primaries: 'bt709',
 			transfer: 'bt709',

tsconfig.vitest.json

@@ -6,7 +6,7 @@
 		"composite": true,
 		"noEmit": false,
 		"paths": {
-			"mediabunny": ["./src/index.ts"],
+			//"mediabunny": ["./src/index.ts"], So that the direct source imports are preferred
 			"@mediabunny/ac3": ["./packages/ac3/src/index.ts"],
 			"@mediabunny/aac-encoder": ["./packages/aac-encoder/src/index.ts"],
 			"@mediabunny/flac-encoder": ["./packages/flac-encoder/src/index.ts"],