Controlling SDP offer contents (RTP session multiplexing, RTP+RTCP multiplexing etc.)

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Raju

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Jun 20, 2012, 8:40:59 PM6/20/12
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Hi All,

We see the following elements in the SDP offer. How can we disable, if we can, each of these from Chrome Canary?

1.
>a=group:BUNDLE audio video
>a=mid:audio 
I assume these are related to RTP session multiplexing.
How to disable RTP session multiplexing?

2.
>m=audio 58876 RTP/SAVPF 103 104 0 8 106 105 13 126
How to make Chrome use RTP/AVP or RTP/SAVP instead of RTP/AVPF?

3.
>a=rtcp-mux
How to disable RTP+RTCP multiplexing?

4. 
>a=ssrc:857843929 label:jY3djXJ6FHgPVBh9VZCSqXm97Ldy2VpIJsfw0
This attribute is in the following draft. How to disable this?

Is there any general documentation about the complete list of these control flags in Chrome Canary (chrome://flags?)?

Thanks for the response.
Raju

Harald Alvestrand

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Jun 21, 2012, 12:57:33 AM6/21/12
to discuss...@googlegroups.com
On Thu, Jun 21, 2012 at 2:40 AM, Raju <mmr...@gmail.com> wrote:
Hi All,

We see the following elements in the SDP offer. How can we disable, if we can, each of these from Chrome Canary?

At the moment, there are no such controls.
 

1.
>a=group:BUNDLE audio video
>a=mid:audio 
I assume these are related to RTP session multiplexing.
How to disable RTP session multiplexing?

Delete the a=group: line.
 
2.
>m=audio 58876 RTP/SAVPF 103 104 0 8 106 105 13 126
How to make Chrome use RTP/AVP or RTP/SAVP instead of RTP/AVPF?

You can't do that. WebRTC does not support an insecure mode.

3.
>a=rtcp-mux
How to disable RTP+RTCP multiplexing?

Delete the line.
 

4. 
>a=ssrc:857843929 label:jY3djXJ6FHgPVBh9VZCSqXm97Ldy2VpIJsfw0
This attribute is in the following draft. How to disable this?

You can't do that. Why would you want to?

Raju

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Jun 22, 2012, 12:39:12 PM6/22/12
to discuss...@googlegroups.com
Thanks for the response.
>You can't do that. Why would you want to?
We wanted to interwork browser and native-IMS clients. Though, we can ignore the parts of SDP offer and exclude themi n SDP answer.
But, in our scenario that approach may not work always.
So, we resorted to updating the SDP generated by createOffer() and/or ignore parts of SDP in SDP offer to suit our needs.

Thanks again!
-Raju

On Wednesday, June 20, 2012 11:57:33 PM UTC-5, Harald Alvestrand wrote:
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