ttml play issue

[kuznetcoff777]

Have you read the FAQ and checked for duplicate issues:yes

What version of Shaka Player are you using: latest

Can you reproduce the issue with our latest release version:demo

Can you reproduce the issue with the latest code from master: demo

Are you using the demo app or your own custom app:demo

If custom app, can you reproduce the issue using our demo app:

What browser and OS are you using: any

What are the manifest and license server URIs:
*(you can send the URIs to shaka-player-issues@google.com instead, but please use GitHub and the template for the rest)*sent to mail

What did you do? Opened stream and waited for subtitles

What did you expect to happen? Subtitles in player

What actually happened? No subs appeared, but in http://dashif.org/reference/players/javascript/v2.5.0/samples/dash-if-reference-player/index.html it works fine. I suppose there is some trouble with ttml itslef, but how to workaround this problem? We need to lauch stream on your player with subtitles.

[theodab]

Looking over the caption mp4s, I think see the problem.
Our mp4 ttml parser assumes that an mp4 will only have a single mdat with ttml inside. These samples, however, have two mdats containing ttml each. Therefore, we end up ignoring the first mdat, and only using the second one... and the second mdat has only a single ttml cue in it, and that cue has a duration of 0.
This should be fairly simple to fix. Thanks for pointing it out.

[kuznetcoff777]

Second mdat is seems to be invalid, i attempted to cut it, but no luck, error 3000 was faced.
Is there any way to make a hot fix on 2.2 version by ourself? We cannot wait for 2.3 version...

[theodab]

Well, I got the change out now, so you can just pull from master.

[theodab]

On reflection I'm not entirely sure if this is a bug, or if it's bad content, but I can't find a spec for ttml in mp4 so I'll leave the bug label for now.
This... bug (?) should be present in 2.0, but this change will only work after the ttml parser refactoring in 2.1.

[kuznetcoff777]

Maybe label is enhancement?
Thanks a lot, it works now.

[joeyparrish]

The fix has been cherry-picked to v2.2.x and will be released in v2.2.2.

[kuznetcoff777]

@theodab @joeyparrish
Guys, have not you destroyed fix in 2.3.0? We checked new version and it seems to be does not work, if button cc is pressed, then captions are not downloaded

[theodab]

I tried it out in the demo. Your example asset doesn't work in the v2.3.0 demo for non-caption-related reasons, but in the nightly build demo it works fine for me. Have you tried out the nightly?