[whatwg] Stream API Feedback

Lachlan Hunt lachlan.hunt at lachy.id.au
Tue Mar 15 03:23:57 PDT 2011

On 2011-03-14 17:59, Lachlan Hunt wrote:
> There are a few issues with the recently added media streaming API.

In addition to what I sent previously, there are some additional use 
cases that do not appear to be addressed adequately by the current spec 
for streaming media.

In chat clients, like Skype, it's common for users to be able to adjust 
the microphone volume or mute the audio stream, or to enable or disable 
the video stream, without interupting the call.  However, the 
GeneratedStream interface only provides a very simple API to pause, 
resume or stop the entire stream, and not individual tracks within the 


var stream;
navigator.getUserMedia("audio,video", success);

function success(s) {
   stream = s;
   // ... Code to make P2P connection for video chat

In this case, stream.pause() will pause both the audio and video 
streams, whereas the user, for example, may just temporarily want to 
pause the video stream, leaving the audio enabled.

While it may be possible for the browser to allow such control entirely 
from the browser chrome, independently of the page, the page author may 
wish to provide customised controls for these features.  I believe the 
API should be adjusted to allow the individual tracks within a stream to 
be paused or resumed independently of each other, and for there to be 
some way to adjust or mute the microphone volume.

Lachlan Hunt - Opera Software

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