Re: MediaStreamTrack behaviuor

Ahh, good! Here's the text:
2.2 MediaStream

The MediaStream() constructor takes two arguments. The arguments are two
lists with MediaStreamTrack<http://dev.w3.org/2011/webrtc/editor/getusermedia.html#idl-def-MediaStreamTrack>
objects
which will be used to construct the audio and video track lists of the new
MediaStream object. When the constructor is invoked, the UA must run the
following steps:

   1.

   Let audioTracks be the constructor’s first argument.
   2.

   Let videoTracks be the constructor’s second argument.
   3.

   Let stream be a newly constructed MediaStream object.
   4.

   Set stream’s label attribute to a newly generated value.
   5.

   If audioTracks is not null, then run the following sub steps for each
   element track in audioTracks:
   1.

      If track is of any other kind than "audio", then throw a SyntaxError
       exception.
      2.

      If track has the same underlying source as another element in
stream’s audio
      track list, then abort these steps.
      3.

      Add track to stream’s audio track list.
      6.

   If videoTracks is not null, then run the following sub steps for each
   element track in videoTracks:
   1.

      If track is of any other kind than "video", then throw a SyntaxError
       exception.
      2.

      If track has the same underlying source as another element in
stream’s video
      track list, then abort these steps.
      3.

      Add track to stream’s video track list.





On Thu, Jul 5, 2012 at 6:12 AM, Anant Narayanan <anant@mozilla.com> wrote:

> On 07/04/2012 05:35 AM, Tommy Widenflycht (ᛏᚮᛘᛘᚤ) wrote:
>
>> I am a bit confused regarding the latest draft regarding how
>> MediaStreamTracks should behave when they are part of more than one
>> MediaStream.
>>
>> It used to be that when a MediaStream was created with a list of Tracks
>> one created new tracks that had the same underlying data source as the
>> input tracks. Basically one cloned the tracks.
>>
>
> This is my understanding as well, if an existing track is added to a new
> MediaStream it should be duplicated even if the source is the same.
>
>
>  Now the draft says that the new MediaStream should add the same Tracks
>> to its lists. That means that the same Track can now belong to more than
>> one MediaStream. This has an unfortunate effect that if one disables a
>> Track, the Track gets disabled in all MediaStreams. It is no longer
>> possible to have independent enabled stated, and for example this basic
>> use case is impossible:
>>
>
> Which part of the spec are you inferring this from in particular? We
> should update the text to be clearer.
>
> Thanks,
> -Anant
>
>


-- 
Tommy Widenflycht, Senior Software Engineer
Google Sweden AB, Kungsbron 2, SE-11122 Stockholm, Sweden
Org. nr. 556656-6880
And yes, I have to include the above in every outgoing email according to
EU law.