Support PGS and VOBSUB subtitles

[wischnow]

Hello,

Issue description

From the documentation and the conversations here I expected PGS and VOBSUB subtitles to work in ExoPlayer, but it seems they are not rendered.

Reproduction steps

Use the ExoPlayer demo app with this sample content from the Kodi repository of samples:

https://drive.google.com/file/d/0BwxFVkl63-lEVEluSFZ4NlhpLUk/view

Link to test content

See above, which is a MKV with PGS.

Unfortunately I don't have a sample with a VOBSUB track that I can share, but those tracks aren't rendered either.

Version of ExoPlayer being used

ExoPlayer version 2.4.2, used via gradle.

Device(s) and version(s) of Android being used

Nexus Player with Android 7.1.2

[ojw28]

I don't think we support either at the moment. Marking as an enhancement. We're unlikely to prioritize this, however, so the most likely path to this being supported would be an external contribution.

[drhill]

I had submitted code awhile back for PGS that was rejected because I translated the ffmpeg implementation into java.

Afterwards I started an implementation from scratch using other sources as documentation. I implemented it in my video app which can be viewed here:

https://github.com/drhill/homeview/tree/master/app/src/main/java/com/monsterbutt/homeview/player/text/pgs

Anyone who wants to take what I did and integrate it into ExoPlayer is welcome to.

[ojw28]

@drhill - If it's just that package (i.e. the three files), and if you could provide a few pieces of test content, then that looks like something we could get merged relatively easily. We'd really need the files sent as a proper pull request from yourself though; it's important that we have a proper attribution trail for all changes we accept. Thanks!

[drhill]

PR: #3673

[ojw28]

PGS is now supported (thanks @drhill!). Assuming VOBSUB is different, I think we'd add support if and only if someone provides a contribution.