- From: Eric Rescorla <ekr@rtfm.com>
- Date: Thu, 25 Aug 2011 09:02:51 -0700
- To: Matthew Kaufman <matthew.kaufman@skype.net>
- Cc: Harald Alvestrand <harald@alvestrand.no>, Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com>, "public-webrtc@w3.org" <public-webrtc@w3.org>
Matthew, Do you think you could sketch out (or point to) what a sample app would look like using this API style? Best, -Ekr On Thu, Aug 25, 2011 at 8:55 AM, Matthew Kaufman <matthew.kaufman@skype.net> wrote: > On 8/24/2011 4:36 AM, Harald Alvestrand wrote: >> >> I think that: >> a) this doesn't make sense - it's a completely new SDP/RTP practice, and >> we should not depart from established practice without a good reason; it >> also flies against the "keep the number of RTP sessions as low as we can" >> conclusion that came out of all the discussions about ICE. >> b) it's not consistent with section 4.1.2 step 7. >> >> I think step 16 of section 4: >> "If connection's ICE started flag is still false, start the PeerConnection >> ICE Agent and send the initial offer. The initial offer must include a media >> description for the PeerConnection data UDP media stream, marked as >> "sendrecv", and for all the streams in localStreams (marked as "sendonly")." >> >> is neither correct nor complete. > > I agree that "this doesn't make sense" and it is just yet another reason > that I think SDP offer-answer is entirely inappropriate for WEBRTC. > > The web user agent should do what the web site's HTML and cooperating > Javascript tell it to do. It should not be engaged in direct negotiation > with the far end such that the outcome is either indeterminate or even > unexpected, except where direct negotiation is explicitly required to meet a > security requirement (the initial ICE handshake to determine that it is > permitted to send data to that endpoint). > > Note that any perceived gains by doing this negotiation (like "what if my > browser is on a slow connection and only wants to receive audio") are > immediately negated the moment the site changes the SDP enroute to add > "wants HD-resolution video" for you. > > In addition, because the spec is currently written with offer-answer, a wide > array of use cases that would be possible if capabilities were instead > exposed via Javascript become impossible. As an example, it should be > possible for me as a web site developer to create a page that can determine, > without prompting you to use your camera, whether or not a camera is > available and if so what codecs it supports. That way I can put "I see you > have a high-resolution camera and can encode H.264 video... click here to > call a live agent who can help you find the exact replacement part" for > users who have that, and not if they don't have a codec that works with my > call center or a camera with sufficient resolution to examine the parts I > sell. > > > Matthew Kaufman > >
Received on Thursday, 25 August 2011 16:04:17 UTC