Feature: allow passing storyboard vtt via attribute

[rmarscher]

Currently, the storyboard only seems to be returned if there is a playback ID.

We mostly use Mux Video, but have some external videos that have a storyboard.vtt in the same format as Mux.

elements/packages/mux-player/src/index.ts

Lines 698 to 716 in a2befb5

	/**
	* Return the storyboard URL when a playback ID is provided,
	* we aren't an audio player and the stream-type isn't live.
	*/
	get storyboard() {
	if (
	this.playbackId &&
	!this.audio &&
	(!this.streamType ||
	![StreamTypes.LIVE, StreamTypes.LL_LIVE, StreamTypes.DVR, StreamTypes.LL_DVR].includes(this.streamType as any))
	) {
	return getStoryboardURLFromPlaybackId(this.playbackId, {
	domain: this.customDomain,
	token: this.tokens.storyboard,
	});
	}
	return;
	}

I think we could update the mux-player package to support passing in a storyboard url instead of only generating from the playback ID.

[dylanjha]

Hi @rmarscher,

Thanks for opening this. Mux player is intended to be used for only Mux sources. The main reason for that is that we can't really make guarantees that the playback engine (Hls.js) and the specific configurations we're using on Hls.js are optimal for any 'ol Hls source.

For that reason we didn't prioritize exposing a config for the storyboard URL, but we'll talk about it and see if we can add this anyway.