HLS subtitles lose role information

[fredrik-telia]

Have you read the FAQ and checked for duplicate open issues?
yes

What version of Shaka Player are you using?
latest

Can you reproduce the issue with our latest release version?
yes

Can you reproduce the issue with the latest code from main?
yes

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

If custom app, can you reproduce the issue using our demo app?
n/a

What browser and OS are you using?
Chrome, macOS

For embedded devices (smart TVs, etc.), what model and firmware version are you using?

What are the manifest and license server URIs?

n/a

What configuration are you using? What is the output of player.getConfiguration()?

n/a

What did you do?

Play HLS content that has both captions and subtitles, the captions having the EXT-MEDIA-TAG as follows:

#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="sub1",LANGUAGE="sv",NAME="Swedish [SDH]",AUTOSELECT=YES,CHARACTERISTICS="public.accessibility.describes-music-and-sound",URI="sc-gaFESg/s2_index.m3u8"

What did you expect to happen?
The subtitle track parsed as having roles: ["public.accessibility.describes-music-and-sound"]

What actually happened?
There is no information in the shaka track object regarding what roles (or kind) this track has, so there is no way of distinguishing it as captions.

I have a fix locally that solves the problem, and could make a pull request. It would be good to have someone with more knowledge of hls_parser.js to take a look at it.

[joeyparrish]

Based on the PR, I think regression was introduced in v4.3.0 with lazy-loading changes. This bug does not appear to affect any other release.