Fwd: draft proposal : active multiple devices for getUserMedia

On Fri, Apr 13, 2012 at 10:58 PM, Adam Bergkvist <
adam.bergkvist@ericsson.com> wrote:

> On 2012-04-12 04:53, William Lin wrote:
>
>> Hi,
>>
>> in these days, Constraints and Capabilities API for getUserMedia were
>> discussed while i found one scenario doesn't be covered:
>> "users may want to initiate capture from multiple devices at one time in
>> multiple media streams" (refer to
>> http://www.w3.org/TR/capture-**scenarios/#multiple-active-**devices<http://www.w3.org/TR/capture-scenarios/#multiple-active-devices>
>> ).
>> is it possible adding the options to set the number of active devices?
>> and the callback function needs to change:
>>
>>
>>        2.1.3 NavigatorUserMediaSuccessCallb**ack
>>
>> [Callback=FunctionOnly, NoInterfaceObject]
>> interfaceNavigatorUserMediaSuc**cessCallback  {
>>     void  handleEvent (LocalMediaStream  stream);
>> };
>>
>> -->
>>
>> [Callback=FunctionOnly, NoInterfaceObject]
>> interfaceNavigatorUserMediaSuc**cessCallback  {
>>     void  handleEvent (LocalMediaStream[]  streams);
>> };
>>
>
> It't true that it's not possible to specify how many devices the app wants
> to get access to. However, the API does support the case where the user
> selects several devices of the same type. The result is one
> LocalMediaStream object with several tracks of each type. The developer can
> then split the single LocalMediaStream by constructing new MediaStream
> objects from the tracks of the LocalMediaStream.
>
> /Adam
>
it is a good idea. Unfortunately, in current spec, we can construct new
MediaStream while no way to stop it(MediaStream can't support stop().) And,
to preview these 'several tracks' in on LocalMediaStream is complicated.

--william