W3C home > Mailing lists > Public > public-media-capture@w3.org > April 2013

Re: addTrack/removeTrack on gUM streams and PeerConnection remote streams

From: Robert O'Callahan <robert@ocallahan.org>
Date: Tue, 16 Apr 2013 00:09:12 +1200
Message-ID: <CAOp6jLYuvNUkpf4M2rqiZBL_=bAfybot4NBUtue3qtLKLge0UQ@mail.gmail.com>
To: Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com>
Cc: "public-media-capture@w3.org" <public-media-capture@w3.org>
On Mon, Apr 15, 2013 at 11:55 PM, Stefan Håkansson LK <
stefan.lk.hakansson@ericsson.com> wrote:

> Yes, they can. But I see a benefit in addTrack e.g. for
>
> * An audio conference with local mixing; there is a button "record"
> available. If one more participant joins, it would be nice if that audio
> track could just be added to the (constructed) MediaStream being recorded.
> Otherwise you'd have to construct a new MediaStream (with all
> participants), start recording it, stop recording the old one - and you
> have to deal with syncing the recorded material
>

This example confuses me. What do you mean by "(constructed) MediaStream"?
I proposed that any MediaStream created by the WebIDL constructors would
support addTrack/removeTrack.

* A device has no camera, a communication session is set up with audio
> only. The user plugs in a camera (which the app can detect with the recent
> additions). It feels like the risk of an audio glitch when playing out at
> the other end would be lower if the video track could just be added rather
> than creating a new MediaStream with both audio and video.
>

This confuses me too. If the app requested audio and video from
getUserMedia, gUM could add the video track automatically when the camera
is attached. Again, my proposal wouldn't affect this.

Rob
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Received on Monday, 15 April 2013 12:09:40 UTC

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