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 <[email protected]> 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 [email protected] https://lists.mozilla.org/listinfo/dev-media
