Hi
Happy new year !
I’d like to add an agenda related to the support of Tracks on SourceBuffer with MSE in a worker.
I’ll be lodging an issue today on GitHub.
In short; when the MediaSource was created in a worker, a SourceBuffer still expose tracks via AudioTrackList / VideoTrackList / TextTrackList
Track objects are currently only exposed at the Window level.
An issue was open to expose them at the Worker level
https://github.com/w3c/media-source/issues/280
Our (webkit) proposal is that tracks shouldn’t be exposed in the worker at all. It doesn’t make much sense to outside the Window and for text track, it’s just not an object that will ever be usable in a Work. TextTrack’s cues can only be rendered via DOM.
Considering no User-Agent currently supports tracks in a worker, I recommend we stop exposing
```
readonly attribute AudioTrackList <https://html.spec.whatwg.org/multipage/media.html#audiotracklist> audioTracks <https://w3c.github.io/media-source/#dom-sourcebuffer-audiotracks>;
readonly attribute VideoTrackList <https://html.spec.whatwg.org/multipage/media.html#videotracklist> videoTracks <https://w3c.github.io/media-source/#dom-sourcebuffer-videotracks>;
readonly attribute TextTrackList <https://html.spec.whatwg.org/multipage/media.html#texttracklist> textTracks <https://w3c.github.io/media-source/#dom-sourcebuffer-texttracks>;
```
When in a worker.
Also related: https://github.com/w3c/media-source/issues/281
> On 10 Jan 2025, at 4:02 am, Chris Needham <chris.needham@bbc.co.uk> wrote:
>
> Hi Media WG,
>
> There's a WG meeting scheduled for Tuesday next week, but I'll be away this time.
>
> The agenda is currently empty, but looking at current activity in GitHub, these might be candidates, although I'm not sure they really need in-person discussion:
>
> Https://github.com/w3c/mediasession/pull/350 <https://github.com/w3c/mediasession/pull/350>
>
> https://github.com/w3c/webcodecs/issues/857
>
> Suggestions for other topics welcome!
>
> Many thanks,
>
> Chris
