I use dto do this regularly a couple of years ago and used to know all the steps to get the RTP streams from Wireshark and then save that into a file and then play it using an application called Audacity.
I think the steps I used to do were:
1. In Wireshark - Setup a display filer for displaying RTP only.
2. Then in Wireshark ----> Under Statistics -----> Show All Streams -----> Then Analyze ------> Then save Payload as "raw" or "au" can't remember - forward / reverse / both
3. Then play the saved file using Audacity.
Am I clear in stating what I need.
Now when I do the above I can't play the file with Audacity.
Audacity did not recognise the type of the file. If it is uncompressed, try importing it using "Import Raw".
One has to keep using these to not forget the steps.
Any help much appreciated.
If you want save and reproduce an audio flow based on RTP G.729 call you can try this procedure:
- save the RTP G.729 Payload in .raw format using wireshark
- convert the .raw file to .pcm using the "open G.729 decoder", see the link http://www.voiceage.com/openinit_g729.php
va_g729_decoder.exe sample.raw sample.pcm.raw
wine va_g729_decoder.exe sample.raw sample.pcm.raw (for linux OS)
- import the new .raw file into Audacity using this options:
- signed 16-bit pc
- no endianness
- 1 channel (mono)
- start offset: 0
- amount to import: 100%
- sample rate: 8000
I'm agree with you, probably the codec used in the call is not G.711.
What is the signalling protocol used in the call? You can find the codec selected during call setup phase.
What is the codec showed from wireshark?
If the RTP stream uses G.711, you can use directly the wireshark audio player:
- in Wireshark - Telephony - Voip Calls
- select a call - then click on Player button
- click on Decode button
- select one or more stream and so click on Play
You can also use RTP analyze tool to save the audio in .au format and play it with Audacity.
If you prefer save the file in .raw format, you can open Audacity and import the file as raw and specify the A-Law codic for G.711A or u-Law coding for G.711u and so the sample frequency equal to 8000 Hz.