fix(HLS): Add subtitle role when there are no roles (#5357)

Fixes #5355 Backported to v4.3.x Co-authored-by: Joey Parrish <[email protected]>
shaka-project · Jul 20, 2023 · 49e3734 · 49e3734
1 parent 98e2c3e
commit 49e3734
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diff --git a/lib/hls/hls_parser.js b/lib/hls/hls_parser.js
@@ -2066,6 +2066,22 @@ shaka.hls.HlsParser = class {
     // stream is lazy-loaded.
     const mimeType = this.guessMimeTypeBeforeLoading_(type, codecs) ||
         this.guessMimeTypeFallback_(type);
+    const roles = [];
+    if (characteristics) {
+      for (const characteristic of characteristics.split(',')) {
+        roles.push(characteristic);
+      }
+    }
+
+    const kind = (type == shaka.util.ManifestParserUtils.ContentType.TEXT) ?
+        shaka.util.ManifestParserUtils.TextStreamKind.SUBTITLE : undefined;
+
+    // If there are no roles, and we have defaulted to the subtitle "kind" for
+    // this track, add the implied subtitle role.
+    if (!roles.length &&
+        kind === shaka.util.ManifestParserUtils.TextStreamKind.SUBTITLE) {
+      roles.push(shaka.util.ManifestParserUtils.TextStreamKind.SUBTITLE);
+    }
 
     return {
       id: this.globalId_++,
@@ -2091,7 +2107,7 @@ shaka.hls.HlsParser = class {
       width: undefined,
       height: undefined,
       bandwidth: undefined,
-      roles: characteristics ? characteristics.split(',') : [],
+      roles,
       forced,
       channelsCount,
       audioSamplingRate: null,

diff --git a/test/hls/hls_parser_unit.js b/test/hls/hls_parser_unit.js
@@ -1150,6 +1150,74 @@ describe('HlsParser', () => {
     await testHlsParser(master, media, manifest);
   });
 
+  it('adds subtitle role when characteristics are empty', async () => {
+    const master = [
+      '#EXTM3U\n',
+      '#EXT-X-STREAM-INF:BANDWIDTH=200,CODECS="avc1",',
+      'RESOLUTION=960x540,FRAME-RATE=60,AUDIO="aud1",SUBTITLES="sub1"\n',
+      'video\n',
+
+      '#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aud1",LANGUAGE="en",',
+      'NAME="English",URI="audio"\n',
+
+      '#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aud1",LANGUAGE="en",',
+      'CHARACTERISTICS="public.accessibility.describes-video,',
+      'public.accessibility.describes-music-and-sound",',
+      'NAME="English (describes-video)",URI="audio2"\n',
+
+      '#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="sub1",LANGUAGE="en",',
+      'NAME="English (subtitle)",DEFAULT=YES,AUTOSELECT=YES,',
+      'URI="text"\n',
+
+      '#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="sub1",LANGUAGE="en",',
+      'NAME="English (caption)",DEFAULT=YES,AUTOSELECT=YES,',
+      'CHARACTERISTICS="public.accessibility.describes-music-and-sound",',
+      'URI="text2"\n',
+    ].join('');
+    const manifest = shaka.test.ManifestGenerator.generate((manifest) => {
+      manifest.anyTimeline();
+      manifest.addPartialVariant((variant) => {
+        variant.language = 'en';
+        variant.addPartialStream(ContentType.VIDEO);
+        variant.addPartialStream(ContentType.AUDIO, (stream) => {
+          stream.language = 'en';
+          stream.roles = [];
+        });
+      });
+      manifest.addPartialVariant((variant) => {
+        variant.language = 'en';
+        variant.addPartialStream(ContentType.VIDEO);
+        variant.addPartialStream(ContentType.AUDIO, (stream) => {
+          stream.language = 'en';
+          stream.roles = [
+            'public.accessibility.describes-video',
+            'public.accessibility.describes-music-and-sound',
+          ];
+        });
+      });
+      manifest.addPartialTextStream((stream) => {
+        stream.language = 'en';
+        stream.kind = TextStreamKind.SUBTITLE;
+        stream.roles = [
+          'subtitle',
+        ];
+      });
+      manifest.addPartialTextStream((stream) => {
+        stream.language = 'en';
+        stream.kind = TextStreamKind.SUBTITLE;
+        stream.roles = [
+          'public.accessibility.describes-music-and-sound',
+        ];
+      });
+      manifest.sequenceMode = true;
+    });
+
+    fakeNetEngine.setResponseText('test:/master', master);
+
+    const actual = await parser.start('test:/master', playerInterface);
+    expect(actual).toEqual(manifest);
+  });
+
   it('parses characteristics from text tags', async () => {
     const master = [
       '#EXTM3U\n',