CEA-708 not rendered on Dolby Vision streams

[benlancaster]

Continuation of #1820.

I don't think the approach in b6baeb6 is working correctly here. For example, I added unit tests in MimeTypesTest.java with the following:

    assertThat(
        MimeTypes.containsCodecsCorrespondingToMimeType(
            /* codecs= */ "dvhe.05.01", MimeTypes.VIDEO_H265))
        .isTrue();

    assertThat(
        MimeTypes.containsCodecsCorrespondingToMimeType(
            /* codecs= */ "dvav.09", MimeTypes.VIDEO_H264))
        .isTrue();

and they fail.

Version

Media3 1.8.0

More version details

Also reproducible on v1.5.1 and v1.6.1

Devices that reproduce the issue

Any Dolby Vision capable device. Reproduced on a Google Chromecast "Sabrina" 4k

Devices that do not reproduce the issue

none that I have found yet

Reproducible in the demo app?

Yes

Reproduction steps

Play a Dolby Vision dvhe.05.01 (Dolby Vision) stream with CEA-708 captions, select a CEA-708 track

Expected result

Captions should render

Actual result

CEA-708 Tracks are selectable, and selected, but no captions rendered

Media

Forthcoming by email

Bug Report

• You will email the zip file produced by adb bugreport to android-media-github@google.com after filing this issue.

[icbaker]

Thanks for reporting. I agree containsCodecsCorrespondingToMimeType doesn't have the correct logic here.

Unfortunately the DRM stream you provided over email isn't compatible with the non-HDCP screen I have connected to the Sabrina device on my desk, so I worked with the MP4 file you provided instead. I had to make a couple of tweaks to make this compatible with ExoPlayer at all:

1. Re-mux as a fragmented MP4 (since we only support CEA-6/708 subs in fragmented MP4 files):

   $ MP4Box -frag 4000 ghi-2775.mp4  -out ghi-2775-frag.mp4

2. Hack DefaultExtractorsFactory to pass a subtitle track into FragmentedMp4Extractor (this usually comes from a DASH manifest, we don't support undeclared CEA-6/708 subtitle tracks in progressive playback of MP4 files):

    case FileTypes.MP4:
      extractors.add(
          new FragmentedMp4Extractor(
              subtitleParserFactory,
              fragmentedMp4Flags
                  | FragmentedMp4Extractor.codecsToParseWithinGopSampleDependenciesAsFlags(
                      codecsToParseWithinGopSampleDependencies)
                  | (textTrackTranscodingEnabled
                      ? 0
                      : FragmentedMp4Extractor.FLAG_EMIT_RAW_SUBTITLE_DATA),
              /* timestampAdjuster= */ null,
              /* sideloadedTrack= */ null,
              ImmutableList.of(
                  new Format.Builder()
                      .setSampleMimeType(MimeTypes.APPLICATION_CEA708)
                      .setAccessibilityChannel(1)
                      .build()),
              /* additionalEmsgTrackOutput= */ null));

---

That got me to a state where I could reproduce your issue, and then tweak the logic in NalUnitUtil to treat dvhe and dvh1 codec strings as H265 for the purposes of NAL unit parsing - which made the subtitles work. I'll send the change for review.

[benlancaster]

@icbaker Came here to open a PR with a similar fix, but I see you've already got it down. Nice one, thanks. I'll give this a spin with our streams now but I see no reason why this wouldn't do the trick 👍🏼

[icbaker]

Thanks for reminding me to close the issue 😂

[benlancaster]

Tested and working with streams I have here. One comment - the h.264 case should never happen, AFAIK, and per my contact at Dolby, DV is always h.265