Re: Replacing an attribute in the SDP

Hello,


On 17.12.25 02:08, David Cunningham via sr-users wrote:
> Hello,
>
> We need to replace a=sendrecv with a=sendonly in the 200 OK reply to
> an INVITE. In theory it should be something straightforward, like in
> the onreply_route using:
>
> replace_body_all( "a=sendrecv", "a=sendonly" );
>
> or:
>
> subst_body( '/^a=sendrecv/a=sendonly/' )
>
> Our first problem is that these both are appending a=sendonly to the
> end of the SDP, not replacing values within it. Does anyone know why
> this might happen?

it could be because of conflicting operations with rtpengine (or
rtpproxy). You could try the replacement in the core reply_route() and
then use msg_apply_changes.


>
> Our second problem is that we really only want to do this for video
> media, and not touch the audio media. Are there any text tools that
> allow you to work with specific media within the SDP?
>
The sdpops has an sdp iterator that could help: once you match the video
stream, look for the sendrecv attrbute and replace the line.

Cheers,
Daniel


-- 
Daniel-Constantin Mierla (@ asipto.com)
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