Add support for MediaStreamTrack.clone() method

[akume]

MediaStreamTrack.clone method hasn't been implemented but it's in the spec.

https://w3c.github.io/mediacapture-main/#dom-mediastreamtrack-clone

[hthetiot]

MediaStream.prototype.clone is implemented, test it and let me know.

• https://github.com/cordova-rtc/cordova-plugin-iosrtc/blob/master/js/MediaStream.js#L293

[hthetiot]

You right MediaStreamTrack is missing.
I will see what I can do.

[hthetiot]

This should works partially.

MediaStreamTrack.prototype.clone = function () {
	debug('clone()');
	return new MediaStreamTrack(this);
};

[stolzda]

I also encountered this issue today. I tried to fix it based on your suggestion @hthetiot , but so far I wasn't successful.

The first thing is that the new track needs a new Id - I could achieve that by just adding a new Id on the javascript side, analogous to MediaStream clone.

However, it doesn't really work because on the swift side the newly cloned MediaStreamTrack should for example be in pluginMediaStreamTracks I guess?

And I don't really understand what the spec means when they write:

Let trackClone's underlying source be the source of track.

Set trackClone's constraints to the active constrains of track.

Is the underlying souce the MediaStream? But what needs to be associated with what?

Can you give so me some hints what is missing there, or do you plan to add this function soon @hthetiot ? Thanks

[hthetiot]

Thank you @stolzda.
We would need something like MediaStream_init (https://github.com/cordova-rtc/cordova-plugin-iosrtc/blob/master/src/iosrtcPlugin.swift#L686) but with the capability of using a source pluginMediaStreamTrack to be clone somewhat before calling MediaStreamTrack_setListener on the new track (https://github.com/cordova-rtc/cordova-plugin-iosrtc/blob/master/src/iosrtcPlugin.swift#L798).

I will look into it when i have a moment, but PR are welcome.

[stolzda]

Yes I was thinking something similar.

In similar terms I think the MediaStream.clone() functionality may be not correct as well - as the specification states, that the associated MediaStreamTracks need to be cloned as well, and since we do not have a method to clone them, probably the current implementation is not correct?

[hthetiot]

@stolzda Yeah MediaStream.clone work but it's a SHAM ;)

[hthetiot]

TODO "the specification states, that the associated MediaStreamTracks need to be cloned"

[hthetiot]

Please try this PR see testing instructions:

#587