Duplicate/Repeated letters in CEA-608 Dash captions

[starchey]

ExoPlayer Version

2.17.1

Devices that reproduce the issue

• Pixel 2 running Android 11
• Has happened on every other emulator, device we've tried as well

Devices that do not reproduce the issue

No response

Reproducible in the demo app?

Not tested

Reproduction steps

1. Setup ExoPlayer with a StyledPlayerView
2. Play a DASH DRM stream with CEA-608 track (ex. https://content.uplynk.com/a0860f48bb8544f5bed2c40d5cc14663.mpd?start=2600&stop=2900), with this license server URL: https://content.uplynk.com/wv
3. Enable any of the caption tracks (e.g. EN)
4. Observe captions on screen

Expected result

Captions display correctly.

Actual result

Observe the captions being displayed with many instances of duplicated letters.

We're not experiencing this on other platforms/players we've tried with the same streams (ex. captions display fine on https://bitmovin.com/demos/drm).

I believe this is the same issue documented here: https://github.com/google/ExoPlayer/issues/9135.

Media

Media URL: https://content.uplynk.com/a0860f48bb8544f5bed2c40d5cc14663.mpd?start=2600&stop=2900 Widevine License Server URL: https://content.uplynk.com/wv

[icbaker]

Thanks for the media link. I can reproduce the problem, however I'm not sure when I'll have time to dig in deeply to understand what's causing it and work out how to fix it. It seems to be relatively rare, because we've only received two reports and our CEA-708 parsing logic doesn't change that quickly - so it's likely that if there's a bug in our library it's been present for a long time. It's possible there's something 'unusual' about the streams in this and #9135 such that it tickles an incompatibility in ExoPlayer.

Would it be possible to provide a single TS file that reproduces the problem (without any DASH or Widevine integration)? That would ensure that when I find the time to look into this I won't have the same problem as #9135 where the link had died. Thanks!

Please either upload it here or send to dev.exoplayer@gmail.com using the subject Issue #10209. Please also update this issue to indicate you’ve done this.