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Harald Welte laforge at gnumonks.orgHi Andreas,
On Mon, Jul 27, 2009 at 07:59:01PM +0200, Harald Welte wrote:
> > i would like to finish audio processing for nanoBTS. can you provide me with
> > some pcap files? a short complete call (few seconds) of one rtp session
> > (including setup, some spoken words, and termination) would help.
>
> I will prepare this for you, no problem. I have the equipment with me and will
> probably send another mail later tonight.
In fact, it was much more difficult than expected. Since I only have one
nanoBTS available right now, all RTP sessions usually originate and terminate
on the device itelf and you never see the RTP streams.
So I've had to add RTP/RTCP proxy functionality to OpenBSC first. Now even calls
between two MS on the same BTS can be routed via the RTP/RTCP proxy (by using
the new "-P" option of bsc_hack).
Using this mode, I have created a pcap file with OML+RSL bringup, followed by
one call between two MS (extn. 1005 calls 1003) where all RTP/RTCP packets are
visible. The call uses EFR, since that is hardcoded in many places all over
OpenBSC at the moment.
The pcap file is available from
http://bs11-abis.gnumonks.org/trac/attachment/wiki/nanoBTS/ipaccess-startup-mo_to_mo_call-proxy.pcap
The call content is an inquiry about the subway schedule between a male and a
female speaker.
Using the rtp_proxy code as a reference, it should be relatively easy to
take those RTP packets and stuff them in TRAU frames (or vice versa), or
passt their content upwards to an application.
Also, we still want to see the TRAU and RTP code move into a separate process.
I've tried to prepare by ths, impementing all RTP related functions in
gsm_04_08 rather than abis_rsl.
Regards,
--
- Harald Welte <laforge at gnumonks.org> http://laforge.gnumonks.org/
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