Add DASH CEA-608 playback test

This was generated by combining the existing `ts/bbb_2500ms.ts` test
asset and a temporary `.srt` file using
https://cloud.google.com/transcoder/docs/how-to/captions-and-subtitles

This doesn't directly reproduce the problem fixed by
7ca26f898d,
because the CEA-608 subs are structured differently to the stream I
discovered the problem with (from Issue: androidx/media#887). However this test
does fail if that fix is reverted after
486230fbd7.

I'm also not able to repro the character duplication reported in
Issue: androidx/media#887 by just changing the manifest in this CL. I'm not yet
sure on the exact differences between the stream provided on GitHub
and this stream.

This stream does provide some regression protection, because it
currently fails with 'new' subtitle parsing
(`DashMediaSource.Factory.experimentalParseSubtitlesDuringExtraction(true)`),
though I'm not sure on the exact reason for that yet.

PiperOrigin-RevId: 592476328

libraries/exoplayer_dash/src/test/java/androidx/media3/exoplayer/dash/e2etest/DashPlaybackTest.java

@@ -167,6 +167,33 @@ public final class DashPlaybackTest {
         applicationContext, playbackOutput, "playbackdumps/dash/ttml-in-mp4.dump");
   }
 
+  @Test
+  public void cea608() throws Exception {
+    Context applicationContext = ApplicationProvider.getApplicationContext();
+    CapturingRenderersFactory capturingRenderersFactory =
+        new CapturingRenderersFactory(applicationContext);
+    // TODO(b/181312195): Opt this test into the new subtitle parsing when it works.
+    ExoPlayer player =
+        new ExoPlayer.Builder(applicationContext, capturingRenderersFactory)
+            .setClock(new FakeClock(/* isAutoAdvancing= */ true))
+            .build();
+    player.setVideoSurface(new Surface(new SurfaceTexture(/* texName= */ 1)));
+    PlaybackOutput playbackOutput = PlaybackOutput.register(player, capturingRenderersFactory);
+
+    // Ensure the subtitle track is selected.
+    DefaultTrackSelector trackSelector =
+        checkNotNull((DefaultTrackSelector) player.getTrackSelector());
+    trackSelector.setParameters(trackSelector.buildUponParameters().setPreferredTextLanguage("en"));
+    player.setMediaItem(MediaItem.fromUri("asset:///media/dash/cea608/manifest.mpd"));
+    player.prepare();
+    player.play();
+    TestPlayerRunHelper.runUntilPlaybackState(player, Player.STATE_ENDED);
+    player.release();
+
+    DumpFileAsserts.assertOutput(
+        applicationContext, playbackOutput, "playbackdumps/dash/cea608.dump");
+  }
+
   // https://github.com/google/ExoPlayer/issues/8710
   @Test
   public void emsgNearToPeriodBoundary() throws Exception {

libraries/test_data/src/test/assets/media/dash/cea608/manifest.mpd

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<MPD xmlns="urn:mpeg:dash:schema:mpd:2011" minBufferTime="PT1.500000S" type="static" xmlns:cenc="urn:mpeg:cenc:2013" mediaPresentationDuration="PT0H0M2.500S" profiles="urn:mpeg:dash:profile:isoff-on-demand:2011">
+  <Period id="0" duration="PT2.500S">
+    <AdaptationSet mimeType="video/mp4">
+      <Accessibility schemeIdUri="urn:scte:dash:cc:cea-608:2015" value="CC1=eng"/>
+      <Representation codecs="avc1.64001e" width="640" height="360" bandwidth="742564" id="sd-dash">
+        <BaseURL>sd-dash0000000000.m4s</BaseURL>
+        <SegmentList presentationTimeOffset="0" duration="24998" timescale="10000">
+          <Initialization range="0-671"/>
+          <SegmentURL mediaRange="672-232714"/>
+        </SegmentList>
+      </Representation>
+    </AdaptationSet>
+    <AdaptationSet mimeType="audio/mp4">
+      <Representation codecs="mp4a.40.2" audioSamplingRate="48000" bandwidth="73273" id="audio-dash">
+        <BaseURL>audio-dash0000000000.m4s</BaseURL>
+        <SegmentList presentationTimeOffset="0" duration="116736" timescale="48000">
+          <Initialization range="0-593"/>
+          <SegmentURL mediaRange="594-22869"/>
+        </SegmentList>
+      </Representation>
+    </AdaptationSet>
+  </Period>
+</MPD>