Fix HLS demuxer parsing bug, extract HLS mime type out, add TargetRequest.mimeType

src/hls/hls-demuxer.ts

@@ -20,7 +20,7 @@ import { TrackType } from '../output';
 import { assert, joinPaths, MaybePromise, Rotation, UNDETERMINED_LANGUAGE } from '../misc';
 import { EncodedPacket } from '../packet';
 import { readAllLines } from '../reader';
-import { AttributeList, canIgnoreLine } from './hls-misc';
+import { AttributeList, canIgnoreLine, HLS_MIME_TYPE } from './hls-misc';
 import { HlsSegmentedInput } from './hls-segmented-input';
 import { PathedSource } from '../source';
 import { SegmentedInputTrackDeclaration } from '../segmented-input';
@@ -105,7 +105,7 @@ export class HlsDemuxer extends Demuxer {
 					if (bandwidth === null) {
 						throw new Error(
 							'Invalid M3U8 file; #EXT-X-STREAM-INF tag requires a BANDWIDTH attribute with a valid'
-							+ ' number value.',
+							+ ' numerical value.',
 						);
 					}
 
@@ -116,7 +116,7 @@ export class HlsDemuxer extends Demuxer {
 						hasOnlyKeyPackets: false,
 					});
 				} else if (line.startsWith('#EXT-X-I-FRAME-STREAM-INF:')) {
-					const attributes = new AttributeList(line.slice(18));
+					const attributes = new AttributeList(line.slice(26));
 					const playlistPath = attributes.get('uri');
 
 					if (playlistPath === null) {
@@ -125,6 +125,14 @@ export class HlsDemuxer extends Demuxer {
 						);
 					}
 
+					const bandwidth = attributes.getAsNumber('bandwidth');
+					if (bandwidth === null) {
+						throw new Error(
+							'Invalid M3U8 file; #EXT-X-I-FRAME-STREAM-INF tag requires a BANDWIDTH attribute with a'
+							+ ' valid numerical value.',
+						);
+					}
+
 					const fullPath = joinPaths(source.rootPath, playlistPath);
 
 					variantStreams.push({
@@ -610,7 +618,7 @@ export class HlsDemuxer extends Demuxer {
 	}
 
 	async getMimeType(): Promise<string> {
-		return 'application/vnd.apple.mpegurl';
+		return HLS_MIME_TYPE;
 	}
 
 	override dispose(): void {

src/hls/hls-misc.ts

@@ -6,6 +6,8 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
+export const HLS_MIME_TYPE = 'application/vnd.apple.mpegurl';
+
 export const canIgnoreLine = (line: string) => line.length === 0 || (line.startsWith('#') && !line.startsWith('#EXT'));
 
 export class AttributeList {

src/hls/hls-muxer.ts

@@ -29,6 +29,7 @@ import { Writer } from '../writer';
 import { EncodedPacket } from '../packet';
 import { SubtitleCue, SubtitleMetadata } from '../subtitles';
 import { NullTarget, PathedTarget, Target, TargetRequest } from '../target';
+import { HLS_MIME_TYPE } from './hls-misc';
 
 type HlsTrackData = {
 	track: OutputTrack;
@@ -499,7 +500,7 @@ export class HlsMuxer extends Muxer {
 	}
 
 	async getMimeType(): Promise<string> {
-		return 'application/vnd.apple.mpegurl';
+		return HLS_MIME_TYPE;
 	}
 
 	private allTracksAreKnown(playlist: Playlist) {
@@ -829,7 +830,11 @@ export class HlsMuxer extends Muxer {
 						relativeSegmentPath,
 					);
 
-					const target = await this.output._getTarget({ path: fullSegmentPath, isRoot: false });
+					const target = await this.output._getTarget({
+						path: fullSegmentPath,
+						isRoot: false,
+						mimeType: playlist.segmentFormat.mimeType,
+					});
 					target._start();
 
 					playlist.singleFile = {
@@ -926,6 +931,7 @@ export class HlsMuxer extends Muxer {
 						const target = await this.output._getTarget({
 							path: initPath,
 							isRoot: false,
+							mimeType: playlist.segmentFormat.mimeType,
 						});
 						target.on('write', ({ end }) => {
 							playlist.initSegment!.byteSize = Math.max(playlist.initSegment!.byteSize, end);
@@ -1179,7 +1185,11 @@ export class HlsMuxer extends Muxer {
 
 		this.format._options.onPlaylist?.(playlistText, toPlaylistInfo(playlist));
 
-		const target = await this.output._getTarget({ path: playlistPath, isRoot: false });
+		const target = await this.output._getTarget({
+			path: playlistPath,
+			isRoot: false,
+			mimeType: HLS_MIME_TYPE,
+		});
 		const writer = new Writer(target);
 		writer.start();
 		writer.write(textEncoder.encode(playlistText));
@@ -1382,7 +1392,11 @@ export class HlsMuxer extends Muxer {
 		} else {
 			// For subsequent master playlist writes, we *must* obtain a different target in order to overwrite
 			// the file.
-			const target = await this.output._getTarget({ path: pathedTarget.rootPath, isRoot: true });
+			const target = await this.output._getTarget({
+				path: pathedTarget.rootPath,
+				isRoot: true,
+				mimeType: HLS_MIME_TYPE,
+			});
 			writer = new Writer(target);
 			writer.start();
 		}

src/input-format.ts

@@ -33,6 +33,7 @@ import { FlacDemuxer } from './flac/flac-demuxer';
 import { MpegTsDemuxer } from './mpeg-ts/mpeg-ts-demuxer';
 import { TS_PACKET_SIZE } from './mpeg-ts/mpeg-ts-misc';
 import { HlsDemuxer } from './hls/hls-demuxer';
+import { HLS_MIME_TYPE } from './hls/hls-misc';
 import { PathedSource } from './source';
 
 /**
@@ -610,7 +611,7 @@ export class HlsInputFormat extends InputFormat {
 	}
 
 	get mimeType() {
-		return 'application/vnd.apple.mpegurl';
+		return HLS_MIME_TYPE;
 	}
 }
 

src/output-format.ts

@@ -29,6 +29,7 @@ import { Output, OutputTrack, TrackType } from './output';
 import { MpegTsMuxer } from './mpeg-ts/mpeg-ts-muxer';
 import { WaveMuxer } from './wave/wave-muxer';
 import { HlsMuxer } from './hls/hls-muxer';
+import { HLS_MIME_TYPE } from './hls/hls-misc';
 import { MaybePromise, FilePath, toArray } from './misc';
 import { Target } from './target';
 
@@ -1368,7 +1369,7 @@ export class HlsOutputFormat extends OutputFormat {
 	}
 
 	get mimeType() {
-		return 'application/vnd.apple.mpegurl';
+		return HLS_MIME_TYPE;
 	}
 
 	getSupportedCodecs(): MediaCodec[] {

src/output.ts

@@ -534,7 +534,11 @@ export class Output<
 			return this._target;
 		}
 
-		const request: TargetRequest = { path: this._target.rootPath, isRoot: true };
+		const request: TargetRequest = {
+			path: this._target.rootPath,
+			isRoot: true,
+			mimeType: this.format.mimeType,
+		};
 		const result = this._getTargetValidated(request);
 
 		const handleResult = (target: T) => {

src/target.ts

@@ -727,6 +727,8 @@ export class PathedTarget<T extends Target> {
 export type TargetRequest = {
 	/** The requested file path. */
 	path: FilePath;
-	/** Whether the requested file is the root file. */
+	/** Whether the to-be-written file will be the root file. */
 	isRoot: boolean;
+	/** The MIME type of the to-be-written file. */
+	mimeType: string;
 };

test/node/hls-input.test.ts

@@ -1,5 +1,5 @@
 /* eslint-disable @stylistic/max-len */
-import { ALL_FORMATS, createInputFrom, EncodedPacketSink, InputAudioTrack, InputVideoTrack } from 'mediabunny';
+import { ALL_FORMATS, BufferSource, createInputFrom, EncodedPacketSink, Input, InputAudioTrack, InputVideoTrack, PathedSource } from 'mediabunny';
 import { expect, test } from 'vitest';
 import { HLS, HlsInputFormat } from '../../src/input-format.js';
 import { assert, rejectAfter } from '../../src/misc.js';
@@ -721,3 +721,45 @@ test.concurrent('Live HLS', { timeout: 30_000 }, async () => {
 	]);
 	expect(metadataDuration).toBeGreaterThan((Date.now() / 1000) - 3600);
 });
+
+test.concurrent('#EXT-X-I-FRAME-STREAM-INF tags are parsed properly', async () => {
+	const text = `#EXTM3U
+#EXT-X-I-FRAME-STREAM-INF:BANDWIDTH=256000,CODECS="avc1.4D401E",RESOLUTION=480x270,URI="7f2459cb12854fdbbc7ec1e7279da179/f74fb10563564130a4702743d64112a3/index_11.m3u8"
+`;
+
+	const input = new Input({
+		formats: ALL_FORMATS,
+		source: new PathedSource('master.m3u8', () => new BufferSource(new TextEncoder().encode(text))),
+	});
+
+	const tracks = await input.getTracks();
+	expect(tracks).toHaveLength(1);
+	expect(await tracks[0]!.hasOnlyKeyPackets()).toBe(true);
+});
+
+test.concurrent('#EXT-X-I-FRAME-STREAM-INF tags without BANDWIDTH attribute are rejected', async () => {
+	const text = `#EXTM3U
+#EXT-X-I-FRAME-STREAM-INF:CODECS="avc1.4D401E",RESOLUTION=480x270,URI="7f2459cb12854fdbbc7ec1e7279da179/f74fb10563564130a4702743d64112a3/index_11.m3u8"
+`;
+
+	const input = new Input({
+		formats: ALL_FORMATS,
+		source: new PathedSource('master.m3u8', () => new BufferSource(new TextEncoder().encode(text))),
+	});
+
+	await expect(input.getTracks()).rejects.toThrow('BANDWIDTH');
+});
+
+test.concurrent('#EXT-X-STREAM-INF tags without BANDWIDTH attribute are rejected', async () => {
+	const text = `#EXTM3U
+#EXT-X-STREAM-INF:CODECS="avc1.4D401E",RESOLUTION=480x270
+7f2459cb12854fdbbc7ec1e7279da179/f74fb10563564130a4702743d64112a3/index_11.m3u8
+`;
+
+	const input = new Input({
+		formats: ALL_FORMATS,
+		source: new PathedSource('master.m3u8', () => new BufferSource(new TextEncoder().encode(text))),
+	});
+
+	await expect(input.getTracks()).rejects.toThrow('BANDWIDTH');
+});