On Wednesday, April 23, 2014 11:54:48 PM UTC-3, Shelly Lin wrote:
> On Thursday, April 24, 2014 12:42:35 AM UTC+8, Martin Thomson wrote:
>
> > On 2014-04-23, at 04:39, Marco Chen wrote:
>
> >
>
> >
>
> >
>
> > > 2. Then there are multiple MediaStreamTrack to represent multiple
> > > audio/video tracks in TV stream.
>
> >
>
> >
>
> >
>
> > I don't know if this is a problem here, or whether it's just a
> > misunderstanding, but the structure of MediaStream is actually three-deep:
>
> >
>
> >
>
> >
>
> > MediaStream is a synchronisation container
>
> >
>
> > MediaStreamTrack describes a single type of related content (e.g., audio,
> > or video)
>
> >
>
> > channels are not visible in the DOM, but they correspond to a single piece
> > of a track (e.g., the left speaker channel in multi-channel audio)
>
> >
>
> >
>
> >
>
> > When you say that there are multiple MediaStreamTrack instances, do you
> > mean to say that there is media from multiple sources (e.g., separate
> > cameras, different translations), or are you talking about media with
> > multiple parts (e.g., 5.1 channel audio)?
>
> >
>
>
>
> The former is closer. A stream can contain multiple tracks, for example, a
> DTV channel provides a program with selection of multiple languages, in this
> case, it is a MediaStream with one VideoSteramTrack and multiple
> AudioStreamTrack, all tracks are from one source. The case with front/back
> camera would be one MediaStream, two VideoStreamTrack, but two sources though.
>
>
>
> >
>
> >
>
> > Why is it necessary for MediaStreamTrack to carry tags that identify things
> > as (for example) English or Mandarin? Is it not possible for this
> > labelling to occur in the application?
>
>
>
> At a second discuss, i don't think there is a need for MediaStreamTrack to
> carry such tags. Nevertheless, the VideoTrack of media elements will carry
> those tags (provided by content provider), in order to let application (e.g.
> a player menu) to display these information for users to select.
Hi, could you please show me an example code of a MediaStream which contains
multiples MediaStreamTrack of multiple cameras. I have been trying to switch
the camera using MediaStream.getVideoTracks(), but there was only one video
track in the stream even though I have two cameras connected.
Thank you!
___
dev-media mailing list
dev-media@lists.mozilla.org
https://lists.mozilla.org/listinfo/dev-media
