Hi,
I've got a problem extracting the audio from RTP packets. I followed the
excellent tips given by Martin Regner on how to deal with not supported
codecs (save full RTP packets, use rtpplay and quicktime to replay and
listen to audio) asdescribed here
(http://www.ethereal.com/lists/ethereal-users/200401/msg00264.html).
I captured the audio stream (AMR 4.75) from a mobile phone (not GSM voice
but VoIP done with a PushtoTalk Java client on the phone) and was able to
convert the log file to the PCAP format. I can open it without any problem
in Ethereal, decode the appropriate UDP packets as RTP, however the payload
is not recognised (Payload type=Unknown (108)).
I prepared an SDP file, which instructs Quicktime for my AMR 4.75 stream I
send with rtpplay but Quicktime doesn't understand what it's getting. Could
it be that rtpplay doesn't deal with the payload properly? Or that Quicktime
doesn't support AMR properly? Or that my log file is not properly converted
to PCAP format? But I can open it and decode RTP, so the payload should be
ok, right?
The media and attributes section of my SDP file:
m=audio 49120 RTP/AVP 97
a=rtpmap:97 AMR/8000/1
a=fmtp:97 mode-set=0,1
a=ptime:20
a=maxptime:20
Any help is highly appreciated!
Regards,
Bernd
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