video resolution in SDP

[Edwin Zhang]

Hi All,

I'm trying to explore the media resolution in SDP offer/answer.

According to the paper (http://tools.ietf.org/id/draft-nandakumar-rtcweb-sdp-01.html), SDP should have "a=ssrc:67890 imageattr:* [x=176,y=144]" in the body to specify the video resolution for the call.

But during my experiment, I cannot find this attribute in my SDP text.

Below is some sample:

m=video 57600 RTP/SAVPF 100 116 117

c=IN IP4 10.230.27.136

a=rtcp:57600 IN IP4 10.230.27.136

a=candidate:1732498890 1 udp 2113937151 10.230.27.136 57600 typ host generation 0

a=candidate:1732498890 2 udp 2113937151 10.230.27.136 57600 typ host generation 0

a=candidate:700459322 1 tcp 1509957375 10.230.27.136 0 typ host generation 0

a=candidate:700459322 2 tcp 1509957375 10.230.27.136 0 typ host generation 0

a=ice-ufrag:fTNwzN1780kbm0o5

a=ice-pwd:+xjIBZBqgiqA31nJFQ+2jd1a

a=ice-options:google-ice

a=fingerprint:sha-256 2C:BB:3F:3B:2A:6F:A0:9D:D9:D3:46:8D:9E:79:3C:43:E8:46:9B:D7:15:D9:E7:5C:41:6D:56:BD:4F:9B:18:3F

a=setup:actpass

a=mid:video

a=extmap:2 urn:ietf:params:rtp-hdrext:toffset

a=extmap:3 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time

a=sendrecv

a=rtcp-mux

a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:mkOzA1xLiCIaISOqqBJSt/H5u7ss70lrKUiwOcNE

a=rtpmap:100 VP8/90000

a=rtcp-fb:100 ccm fir

a=rtcp-fb:100 nack

a=rtcp-fb:100 goog-remb

a=rtpmap:116 red/90000

a=rtpmap:117 ulpfec/90000

a=ssrc:2325553971 cname:yCmsPzlII/mrcyXz

a=ssrc:2325553971 msid:qiZeIUXmxNA4te2tLvc8H3fC0EZ8aGLrc40H e0b1f346-1039-4de0-b34e-d6c1d91233dc

a=ssrc:2325553971 mslabel:qiZeIUXmxNA4te2tLvc8H3fC0EZ8aGLrc40H

a=ssrc:2325553971 label:e0b1f346-1039-4de0-b34e-d6c1d91233dc

I also tried different mediaContraint in getUserMedia() api to get different resolution streams, but the SDP always looks similar to me.

Can anyone let me know where do I get the media resolution in the SDP?

Also, is it possible to include multiple resolution options in the SDP offer?

Thanks.

Edwin

[Justin Uberti]

This is not currently supported; the draft you mention is an examples draft and not normative.

There has been a fair amount of discussion on this, but the exact mechanism is still being determined. Most likely applications will adjust the resolution manually using knobs on the capture-side MediaStreamTrack.

--
 
---
You received this message because you are subscribed to the Google Groups "discuss-webrtc" group.
To unsubscribe from this group and stop receiving emails from it, send an email to discuss-webrt...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.