Fix interleaving of chunks in finalize()

dev/index.html

@@ -39,7 +39,7 @@
 	const context = canvas.getContext('2d');
 
 	let format = new Metamuxer.WebMOutputFormat({ streamable: false });
-	//format = new Metamuxer.Mp4OutputFormat({ fastStart: false }); // new Metamuxer.MkvOutputFormat();// new Metamuxer.Mp4OutputFormat({ fastStart: false });
+	format = new Metamuxer.Mp4OutputFormat({ fastStart: 'fragmented' }); // new Metamuxer.MkvOutputFormat();// new Metamuxer.Mp4OutputFormat({ fastStart: false });
 	let target = new Metamuxer.BufferTarget();
 
 	/*
@@ -95,7 +95,7 @@
 
 	output.addVideoTrack(videoSource);
 	output.addAudioTrack(audioSource);
-	//output.addSubtitleTrack(subtitleSource);
+	output.addSubtitleTrack(subtitleSource);
 
 	output.start();
 
@@ -174,5 +174,5 @@ Testing... <00:17.350>One... <00:18.125>Two...
 	await output.finalize();
 
 	console.log(target);
-	download(new Blob([target.buffer]), 'test.webm');
+	download(new Blob([target.buffer]), 'test.mp4');
 </script>

src/isobmff/isobmff-muxer.ts

@@ -743,14 +743,16 @@ export class IsobmffMuxer extends Muxer {
 		await this.writer.flush();
 	}
 
-	private async interleaveSamples() {
+	private async interleaveSamples(isFinalCall = false) {
 		assert(this.fastStart === 'fragmented');
 
+		if (!isFinalCall) {
 			for (const track of this.output._tracks) {
 				if (!track.source._closed && !this.trackDatas.some(x => x.track === track)) {
 					return; // We haven't seen a sample from this open track yet
 				}
 			}
+		}
 
 		outer:
 		while (true) {
@@ -758,7 +760,7 @@ export class IsobmffMuxer extends Muxer {
 			let minTimestamp = Infinity;
 
 			for (const trackData of this.trackDatas) {
-				if (trackData.sampleQueue.length === 0 && !trackData.track.source._closed) {
+				if (!isFinalCall && trackData.sampleQueue.length === 0 && !trackData.track.source._closed) {
 					break outer;
 				}
 
@@ -878,14 +880,7 @@ export class IsobmffMuxer extends Muxer {
 		}
 
 		if (this.fastStart === 'fragmented') {
-			for (const trackData of this.trackDatas) {
+			await this.interleaveSamples(true);
-				for (const sample of trackData.sampleQueue) {
-					await this.addSampleToTrack(trackData, sample);
-				}
-
-				this.processTimestamps(trackData);
-			}
-
 			await this.finalizeFragment(false); // Don't flush the last fragment as we will flush it with the mfra box
 		} else {
 			for (const trackData of this.trackDatas) {

src/matroska/matroska-muxer.ts

@@ -496,12 +496,14 @@ export class MatroskaMuxer extends Muxer {
 		}
 	}
 
-	private async interleaveChunks() {
+	private async interleaveChunks(isFinalCall = false) {
+		if (!isFinalCall) {
 			for (const track of this.output._tracks) {
 				if (!track.source._closed && !this.trackDatas.some(x => x.track === track)) {
 					return; // We haven't seen a sample from this open track yet
 				}
 			}
+		}
 
 		outer:
 		while (true) {
@@ -509,7 +511,7 @@ export class MatroskaMuxer extends Muxer {
 			let minTimestamp = Infinity;
 
 			for (const trackData of this.trackDatas) {
-				if (trackData.chunkQueue.length === 0 && !trackData.track.source._closed) {
+				if (!isFinalCall && trackData.chunkQueue.length === 0 && !trackData.track.source._closed) {
 					break outer;
 				}
 
@@ -527,8 +529,10 @@ export class MatroskaMuxer extends Muxer {
 			this.writeBlock(trackWithMinTimestamp, chunk);
 		}
 
+		if (!isFinalCall) {
 			await this.writer.flush();
 		}
+	}
 
 	/** Due to [a bug in Chromium](https://bugs.chromium.org/p/chromium/issues/detail?id=1377842), VP9 streams often
 	 * lack color space information. This method patches in that information. */
@@ -764,11 +768,7 @@ export class MatroskaMuxer extends Muxer {
 		}
 
 		// Flush any remaining queued chunks to the file
-		for (const trackData of this.trackDatas) {
+		await this.interleaveChunks(true);
-			while (trackData.chunkQueue.length > 0) {
-				this.writeBlock(trackData, trackData.chunkQueue.shift()!);
-			}
-		}
 
 		if (!this.format._options.streamable && this.currentCluster) {
 			this.finalizeCurrentCluster();

todo.txt

@@ -6,4 +6,3 @@
 - onHeader, etc callbacks for Matroska
 - https://github.com/Vanilagy/mp4-muxer/issues/83 tell him it's possible now
 - Matroska projection for video rotation in muxer
-- Fix interleaving at the end in finalize!!