Add e2e test for seeking to beginning of chunk

RELEASENOTES.md

@@ -23,6 +23,8 @@
 *   Cronet Extension:
 *   RTMP Extension:
 *   HLS Extension:
+    *   Resolve seeks to beginning of a segment more efficiently
+        ([#1031](https://github.com/androidx/media/pull/1031)).
 *   DASH Extension:
 *   Smooth Streaming Extension:
 *   RTSP Extension:

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

@@ -242,7 +242,7 @@ public TrackGroup getTrackGroup() {
     return trackGroup;
   }
 
-  /** Returns if the chunk source has independent segments. */
+  /** Returns whether the chunk source has independent segments. */
   public boolean hasIndependentSegments() {
     return independentSegments;
   }

libraries/exoplayer_hls/src/test/java/androidx/media3/exoplayer/hls/e2etest/HlsPlaybackTest.java

@@ -23,6 +23,7 @@
 import androidx.media3.common.Player;
 import androidx.media3.datasource.DefaultDataSource;
 import androidx.media3.exoplayer.ExoPlayer;
+import androidx.media3.exoplayer.SeekParameters;
 import androidx.media3.exoplayer.hls.HlsMediaSource;
 import androidx.media3.test.utils.CapturingRenderersFactory;
 import androidx.media3.test.utils.DumpFileAsserts;
@@ -153,4 +154,37 @@ public void cea608_parseDuringExtraction() throws Exception {
     DumpFileAsserts.assertOutput(
         applicationContext, playbackOutput, "playbackdumps/hls/cea608.dump");
   }
+
+  @Test
+  public void multiSegment_withSeekToPrevSyncFrame_startsRenderingAtBeginningOfSegment()
+      throws Exception {
+    Context applicationContext = ApplicationProvider.getApplicationContext();
+    CapturingRenderersFactory capturingRenderersFactory =
+        new CapturingRenderersFactory(applicationContext);
+    ExoPlayer player =
+        new ExoPlayer.Builder(applicationContext, capturingRenderersFactory)
+            .setMediaSourceFactory(
+                new HlsMediaSource.Factory(new DefaultDataSource.Factory(applicationContext))
+                    .experimentalParseSubtitlesDuringExtraction(true))
+            .setClock(new FakeClock(/* isAutoAdvancing= */ true))
+            .build();
+    // Prepare media fully to ensure we have all the segment data available.
+    player.setVideoSurface(new Surface(new SurfaceTexture(/* texName= */ 1)));
+    PlaybackOutput playbackOutput = PlaybackOutput.register(player, capturingRenderersFactory);
+    player.setMediaItem(MediaItem.fromUri("asset:///media/hls/multi-segment/playlist.m3u8"));
+    player.prepare();
+    TestPlayerRunHelper.runUntilIsLoading(player, true);
+    TestPlayerRunHelper.runUntilIsLoading(player, false);
+
+    // Seek to beginning of second segment (at 500ms according to playlist)
+    player.setSeekParameters(SeekParameters.PREVIOUS_SYNC);
+    player.seekTo(600);
+    player.play();
+    TestPlayerRunHelper.runUntilPlaybackState(player, Player.STATE_ENDED);
+    player.release();
+
+    // Output only starts at 550ms (the first sample in the second segment)
+    DumpFileAsserts.assertOutput(
+        applicationContext, playbackOutput, "playbackdumps/hls/multi-segment-with-seek.dump");
+  }
 }

libraries/test_data/src/test/assets/media/hls/multi-segment/playlist.m3u8

@@ -0,0 +1,11 @@
+#EXTM3U
+#EXT-X-VERSION:7
+#EXT-X-TARGETDURATION:1
+#EXT-X-MEDIA-SEQUENCE:0
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-MAP:URI="init.mp4"
+#EXTINF:0.500,
+playlist0.m4s
+#EXTINF:0.550,
+playlist1.m4s
+#EXT-X-ENDLIST