Add subtitle parsing support in HLS for TS files

PiperOrigin-RevId: 582714493

RELEASENOTES.md

@@ -72,8 +72,6 @@
     *   Add experimental support for parsing subtitles during extraction. You
         can enable this using
         `HlsMediaSource.Factory.experimentalParseSubtitlesDuringExtraction()`.
-        This works for standalone WebVTT subtitles and IMSC1 subtitles muxed
-        into MP4.
 *   DASH Extension:
     *   Extend experimental support for parsing subtitles during extraction to
         work with standalone text files (previously it only worked with

libraries/exoplayer_hls/src/main/java/androidx/media3/exoplayer/hls/DefaultHlsExtractorFactory.java

@@ -207,12 +207,16 @@ public final class DefaultHlsExtractorFactory implements HlsExtractorFactory {
             ? new SubtitleTranscodingExtractor(mp4Extractor, subtitleParserFactory)
             : mp4Extractor;
       case FileTypes.TS:
-        return createTsExtractor(
-            payloadReaderFactoryFlags,
-            exposeCea608WhenMissingDeclarations,
-            format,
-            muxedCaptionFormats,
-            timestampAdjuster);
+        Extractor tsExtractor =
+            createTsExtractor(
+                payloadReaderFactoryFlags,
+                exposeCea608WhenMissingDeclarations,
+                format,
+                muxedCaptionFormats,
+                timestampAdjuster);
+        return subtitleParserFactory != null
+            ? new SubtitleTranscodingExtractor(tsExtractor, subtitleParserFactory)
+            : tsExtractor;
       default:
         return null;
     }