[SR-Users] sdp manipulation in connection with rtpengine_offer/answer calls

[Daniel-Constantin Mierla]

On 10/08/15 09:49, Juha Heinanen wrote:
> Daniel-Constantin Mierla writes:
>
>> iirc, based on what was discussed on the mailing list, at least in some
>> cases, the full sdp is sent to rtpengine and then full sdp would be
>> returned.
> That is clear, but which "full" sdp:  the original one or the one
> changed by previous sdpops calls?

I expect to be the originial one.

>
>> It doesn't do any use of sdpops module.
> That is clear too.
>
>> You should use
>> msg_apply_changes() in between them in order to have previous changes
>> visible for further processing.
> Do you mean that msg_apply_changes() needs to be called between each
> sdpops call?  I thought that the changes made by sdpops calls are
> cumulative.
>
Some of the sdpops functions were added by others, but I expect they
still use the lump mechanism as those I did, so the changes are not
immediately visible.

You don't need to do msg_apply_changes() after each sdpops change,
unless you want that preview change to be visible for next operations.

For example, you can call the function to remove a codec twice, once for
g711 and once for g729 without msg_apply_change() and all should be fine.

However, if you want to remove video media stream and then call
rtpengine/rtpproxy, then the msg_apply_changes() would be required in
order for rtp relay application not to see the video stream.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
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