how to decode RTP payload MSN audio conversation?

[denemeler]

Hi

I have some rtp packet. I want to decode rtp payload. I know farsight doing that but there is no sip packet only rtp.
Can I do that with farsight even if there is no sip packet?
if I can do, How can I do with farsight?
I want to appreciate if you give some tips.

thanks

[kakaroto]

hi..
well, this is an amsn forum, not a SIP/RTP forum, I suggest you read the RFCs about RTP to see how you can depayload it....
in short, it will depend on the packet, you read the RTP header, then depending on the payload type, you would know which codec is contained in it, and each codec would have its own depayloader, and the depayloader would read an extra header if it exists (depends on the codec) with varying length (depends on the codec), then would read the payload.
SIP is useful here because it gives you a mapping between payload types (dynamic) and the codecs they represent.. without SIP, you only have a number (payload type) and have no way of knowing which codec it refers to, so you have no way of knowing how to depayload it...
each codec has an RFC describing how to payload/depayload it.. use google!