ExoPlayer requires text track duration not to be shorter than video/audio duration

[kqyang]

See google/ExoPlayer#3317 and google/ExoPlayer#4029, ExoPlayer (v2.6.1) calculates media duration from the shortest Representation. So if text tracks end early, ExoPlayer won't play all the way to the end of the media.

We need to pad subtitle tracks with empty chunks, extending them to match with video duration. That is not required by DASH spec, but it is the only way to make it work on ExoPlayer.

[ojw28]

As per the ExoPlayer issue, we will endeavor to support this case primarily due to the time that will be required to update packagers such as shaka to pad representations with empty segments, and also due to existing content that's already been packaged.

However, since the DASH-IF discussion appears to be headed in the direction of recommending padding segments, I'd expect this issue to remain open and be addressed in shaka packager at some point (unless the DASH-IF discussion changes course and short representations end up being explicitly allowed).

[kqyang]

@ojw28 Thanks! Move this issue to backlog for now. We will review again once DASH-IF discussion is finalized.

[okycelt]

Hello, do you have any update on this?

[kqyang]

@okycelt This is low priority for us right now as it is no longer a problem in ExoPlayer. Let us know if you think we should bump the priority.

[okycelt]

@kqyang Sorry, we've missed that ExoPlayer is supporting this already. We're using 2.8.2, will try with the latest version. Thank you for your quick response.