Success & Failure Callbacks in RTCRtpSender.setTrack

[aboba]

Mozilla proposal for RTCRtpSender.replaceTrack method:
http://lists.w3.org/Archives/Public/public-webrtc/2014Sep/0001.html

Difference from RTCRtpSender.setTrack is use of a success and failure callback.

[aboba]

Reply from Martin Thomson:
http://lists.w3.org/Archives/Public/public-webrtc/2014Sep/0011.html

[aboba]

WebRTC 1.0 PR for replaceTrack:
w3c/webrtc-pc#195

[aboba]

Proposal is to change setTrack to a Promise for consistency with WebRTC 1.0.

[aboba]

Here is the proposed replacement text in Section 6.3.2:

setTrack
Attempts to replace the track being sent with another track provided.

When the setTrack() method is invoked, the user agent must run the following steps:

Let p be a new promise.

Let withTrack be the argument to this method.

Run the following steps asynchronously:

If withTrack.kind differs from RTCRtpSender.track.kind or if withTrack has different peerIdentity constraints, then reject p with IncompatibleMediaStreamTrackError and abort these steps.

Set the RTCRtpSender.track attribute to withTrack, and have the sender seamlessly switch to transmitting withTrack in place of what it is sending. On the remote receiving end, the track maintains its existing grouping and id until the connection ends.
Parameter Type Nullable Optional Description
track MediaStreamTrack ✘ ✘
Return type: Promise