WebVTT issues with Firefox 50

[benjaoming]

Description

I've found that WebVTT with vtt.js is broken in Firefox 50. This is elaborated here: mozilla/vtt.js#354

The PR that fixes it hasn't been merged and released yet:

The PR with the fix has been merged and is waiting to be released:

mozilla/vtt.js#359

This issue can be fixed once 0.13.0 of vtt.js is released, which it seems they want to do once the PR is merged.

Steps to reproduce

Please see the issues in vtt.js

Additional Information

Please include any additional information necessary here. Including the following:

versions

videojs

Same errors in 5.8.0, 5.12.6, and latest 5.13.2 release

browsers

Firefox 50

OSes

All AFAIK

[benjaoming]

I have a built fork of video.js master here: https://github.com/learningequality/video.js/tree/firefox50-dist which is using a vtt.js build from my own git repo.

[gkatsev]

I'm trying it locally and I'm not seeing any issues. Do you happen to have a reduced test case? Does it happen with the current releases or with a version of vtt.js from master?
We're currently on a forked version for various reasons, one of which being the use of vttjs's VTTCues rather than native cues when possible

[benjaoming]

@gkatsev

Do you happen to have a reduced test case?

No :( I can't reproduce it with the CDN version in FF 50. Maybe it is - as you say - an error that has already been patched in your vtt.js fork.

Does it happen with the current releases or with a version of vtt.js from master?

It's the current vtt.js release 0.12.1, the issue is already identified and a PR open in Mozilla's repo as stated.

So just to summarize: This issue does not affect the video.js CDN built, but would it still affect self-hosted and other types of source builds that include vtt.js, and is this even supported?

Is there a way to be running self-hosted stuff with the video.js fork of vtt.js? Or is there a way for these changes to make it back upstream or video.js to switch back to Mozilla's releases?

Please correct me if I was jumping to conclusions :)