Re: [Ccrtp-devel] about rtpsend and rtplisten

[Federico Montesino Pouzols]

On Mon, Dec 23, 2002 at 08:26:59PM +0800, karl wrote:
> Yes, you are right. 
> Now I update the ccRTP to 1.0pre1 and recompiled demos.
> At majority time, it is normal. But sometimes when I send 2 packets,
> rtplisten received 1 only 

        This should not happen. If it is a bug, I would need a more
complete report including command lines, output, etc. so that I can
figure out what may be going on.

>and been sending out following information all the time, never stop:
> I got a SDES chunk from address@hidden:1067
> I got an RR RTCP report from address@hidden:1067
> ....

        Well, if the sender does not stop (does not send a BYE RTCP
packet), it will keep sending RTCP packets at a pseudo-periodic rate
even if it is not sending data. This is the standard behaviour.


> Besides these in the above,  there is another problem:
> When I receive   RTP streaming with rtplisten and store it to a file, the 
> noise is very great.
> 

        Do you mean audiotx and audiorx? Yes, the sound quality is
awful because mu-law encoding is not correctly handled...

> 
>  I want to write a program that  receive a RTP packet , remove it's header ,  
>  get it's data
>  (no matter what format it is) and deposit the data in a file. 
> Another program finish opposite function , that is , open a file,
>  make it's data into RTP packets, then send out them, no matter what format 
> the data in the file are.
> 
> Can the ccRTP finish these?  if it can, how should my program write ?
> Would you like to write a demo for me?
> 

        audiotx and audiorx do basically that, though at a fixed rate
for PCMU audio. If you look at the code, you will see that audio
coding/decoding is rudimentaryly done reading and writing from/to the
/dev/audio device file. You would only need to change the file and
handle the file ending.

        I thought that improving the audio coding/decoding would add
unneeded complexity for a simple demo. Anyway, and that was suggested
some time ago, it would be interesting to modify audiotx and audiorx
so that they can read and write to the standard input/output. It will
be done in a few days, when I finish some other improvements for
ccRTP.

> I download a rtp-1.4.0 from www.vovida.org. 
>  it can record and play voice very good. But it convert codes form one format 
> to another.
> However, I do not need these functions.
> Would  you like to tell me a good method?
> 
> Thanks for your long-term help.
>