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Re: Resolution changes

From: Martin Thomson <martin.thomson@gmail.com>
Date: Tue, 15 Sep 2015 15:18:15 -0700
Message-ID: <CABkgnnXUR8aBEZ-D1WgcbAonqjrC5e5Vh6ZaS8JYcOhpxq1pcg@mail.gmail.com>
To: Harald Alvestrand <harald@alvestrand.no>
Cc: Jan-Ivar Bruaroey <jib@mozilla.com>, "public-webrtc@w3.org" <public-webrtc@w3.org>
On 15 September 2015 at 15:00, Harald Alvestrand <harald@alvestrand.no> wrote:
> Martin, can you clarify what you were asking?

I'll try to make this as precise as possible:

Premise 1: The resolution of a MediaStreamTrack is not constrained by
RTCPeerConnection.
Premise 2: RTCPeerConnection can negotiate a session that places
limits on the resolution of video that it can transmit.
Conclusion: MediaStreamTrack might produce a resolution that
RTCPeerConnection cannot convey.

Yes, the point is that the source might change.  The common case -
where MediaStreamTrack is not constrained in any way - would easily
allow this to happen.

> I did not understand Martin to ask about what happens when the negotiation
> window on a PeerConnection that is a sink to a MediaStreamTrack changes -
> that's a completely different problem, and I agree that the spec is silent
> on what should happen then.

Yes, I did not ask that question because I believe it to be a
non-issue.  Negotiation is informed by the state of the
MediaStreamTrack.  RTCPeerConnection should not renegotiate something
that the MediaStreamTrack is incapable of producing.
Received on Tuesday, 15 September 2015 22:18:43 UTC

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