["Anders Broman (AL/EAB)" <anders.broman@xxxxxxxxxxxx>]

Hi,
Regarding "108" it is a dynamic payload type ( 96 - 127 )what this payload type will be is
"signaled" between the "server" and "host" in your perticular case 108 "is" AMR
as quicktime does not know of the signaling you must "tell" it by the SDP data.
> > 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
m=audio 49120 RTP/AVP 97 Tells it that m(edia) is araving at port 49120 format is RTP/AVP
a=rtpmap:97 AMR/8000/1 Tells it ( check the SDP RFC http://www.ietf.org/rfc/rfc2327.txt?number=2327 and
http://www.iana.org/assignments/rtp-parameters ).
 .../AMR/8000 where 8000 is 8khz
perhaps you should change this to 4750 ? 
Best regards
Anders

-----Original Message-----
From: ethereal-users-bounces@xxxxxxxxxxxx
[mailto:ethereal-users-bounces@xxxxxxxxxxxx]On Behalf Of Bernd Brantner
Sent: den 4 augusti 2004 15:41
To: ethereal-users@xxxxxxxxxxxx
Subject: RE: [Ethereal-users] Replay audio from RTP with AMR payload 


All,

replacing 97 with 108 makes a difference, thanks (I thought 108 is just the
code for unrecognised payload. Now Quicktime recognises AMR Narrowband,
Mono, 8000Hz. And it starts to play "twitch" sounds aka "dolphin sounds" for
half a second (but not for the whole length of play) when I use rtpplay with
option -T; and for the whole length without -T.

RTP should be fine as it can be replayed by rtpplay, timestamp is also
incrementing. This sound seems to indicate an incorrect decoding. Any
further ideas?

Regards,
Bernd


> Subject: RE: [Ethereal-users] Replay audio from RTP with AMR payload 
> From: "Anders Broman (AL/EAB)" <anders.broman@xxxxxxxxxxxx> 
> Date: Tue, 3 Aug 2004 17:02:06 +0200 
> 
>
--------------------------------------------------------------------------------
> 
> Hi,
> I think the problem may be the SDP file, shouldn't 97 be replaced with 108
in this case?
>  As 108 is the payload type in this particular case and was 97 in the
example given by Martin ?.
> Best regards
> Anders
> 
> -----Original Message-----
> From: ethereal-users-bounces@xxxxxxxxxxxx
> [mailto:ethereal-users-bounces@xxxxxxxxxxxx]On Behalf Of Lars Ruoff
> Sent: den 3 augusti 2004 16:26
> To: Ethereal user support
> Subject: Re: [Ethereal-users] Replay audio from RTP with AMR payload
> 
> 
> 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)).
> 
> AMR is a dynamic payload type, which aren't handled by Ethereal to my
> knowledge (?).
> However, exporting the RTP packets via "Save as rtpdump" should still
work!
> 
> >
> > 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?
> 
> No, rtpplay doesnt even know about payload. It dumbly replays RTP packets,
> whatever the payload might be.
> There might however be an issue with your version of rtpplay using a
> different file format than Ethereal (unfortunately, rtpdump file format
has
> not been specified in a compiler-independent way). To test: let rtpplay
> replay the packets to some dummy IP, then capture those packets again with
> Etherel and see if they're still the same as the original ones.
> 
> > Or that Quicktime
> > doesn't support AMR properly?
> 
> Most likely. However i dont know Quicktime myself.
> 
> > 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?
> 
> Yes. most likely. Check if the other RTP fields make sense.
> (SSRC stays the same, timestamps increment etc.)
> 
> >
> > 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
> 
> Martin might have additional info on the Quicktime specific issues.
> 
> regards,
> Lars Ruoff
> 
> _______________________________________________
> Ethereal-users mailing list
> Ethereal-users@xxxxxxxxxxxx
> http://www.ethereal.com/mailman/listinfo/ethereal-users
> 
> 

-- 
NEU: WLAN-Router für 0,- EUR* - auch für DSL-Wechsler!
GMX DSL = supergünstig & kabellos http://www.gmx.net/de/go/dsl

_______________________________________________
Ethereal-users mailing list
Ethereal-users@xxxxxxxxxxxx
http://www.ethereal.com/mailman/listinfo/ethereal-users