ip.access RTP capture using Version 1 (FR) codec

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Dieter Spaar spaar at mirider.augusta.de
Wed Jul 29 16:06:12 UTC 2009


Hello Harald,

On Wed, 29 Jul 2009 15:48:32 +0200, "Harald Welte" <laforge at gnumonks.org> wrote:
> 
> I'm telling you, OpenBSC's RTP proxy works fine.   I've just made another call
> and there are no drop-outs of .8 seconds or anything like that.

I am sure that the proxy is working, I never doubt that. I guess for some
reason Wireshark is just missing the data. I was joking about Windows
versus Linux performance, but maybe this was not clear enough.

> As all it uses is the sockets API, i.e. the very same calls that the
> input/ipaccess.c module already uses, I think it should be very easy to make it
> build using the posix compatibility of cygwin.

I tried it in the meantime. No problem at all. The git version works
as expected and Wireshark does not miss any packets here, each call
is about 30 seconds. I tried it with EFR and FR, Wireshark can
save the RTP payload, for EFR I had to convert the data first so
that they fit to the GSM 06.35 reference implementation (they use
a strange format which stores every bit into two bytes). For FR,
Toast can convert the payload immediately. Tested on Windows XP
and cygwin, Wireshark and bsc_hack running on the same machine.

Best regards,
  Dieter
-- 
Dieter Spaar, Germany                           spaar at mirider.augusta.de




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