[PATCH 4/4] mgcp/rtp: Fix timestamp offset when patching RTP packets

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Jacob Erlbeck jerlbeck at sysmocom.de
Fri Nov 22 09:39:00 UTC 2013


On 11/22/2013 10:22 AM, Holger Hans Peter Freyther wrote:
> On Fri, Nov 22, 2013 at 09:59:10AM +0100, Jacob Erlbeck wrote:
> 
>> We can, but then I would like to put all of the above into the rtp_end
>> structure.
> 
> sure.

Ok, then I'll refactor it this way.

> 
>> Currently (with and without the patch) the packet is only patched after
>> SSRC changes.
> 
> It was my understanding that the TS issue we were seing also appeared
> without a change in the SSRC? In case this is something I asked you to
> do after this patch we can postpone this discussion.

We've settled to just add counters and not to fix the timing for streams
with a constant SSRC yet. So I'd rather put that feature into another
commit after we've decided on the concept.

> 
>> just based on heuristics and may fail theoretically.
> 
> SCNR: And in theory ip.access should be able to create working software
> with the capital they received. ;)

And the audio source should deliver non-broken audio streams either.

> 
> I would like to understand if the TS problem only occurs when the TS is
> changing or if the ts_delta issue is only introduced by the patching I
> do.

The TS problem in question only occured within streams of a singly SSRC
and are thus not fixed by the patch (but detected).

I've only fixed the SSRC patching because I didn't want the osmo MGW/NAT
to introduce the same kind of errors we are getting from the other audio
source.

Jacob




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