Re: [Linphone-developers] rtp_session_recv_with_ts and buffer length

[Nicholas J Humfrey]

Yes - I was incrementing by 160 each time. The reason I didn't know  
what size buffer I needed was because I have been writing a perl  
module, which uses oRTP. So I wanted to be able to write:

my $data = $rtp->recv_with_ts( $timestamp );

For the time being I have just added a $bytes parameter to indicate  
the desired number of bytes:

my $data = $rtp->recv_with_ts( $timestamp, $bytes );


I have just released the first version of the perl module:

http://search.cpan.org/dist/Net-RTP/

I will continue working on it to implement some of the lower level  
oRTP API too, as I have described in the README file. It will include  
a Net::RTP::Packet package, to receive packets  
rtp_session_recvm_with_ts() style.


Using perl to do RTP does indeed seem a little odd - my main  
intention was to use it for testing and debugging. However I have  
written a little perl script called rtpsendbeeps.pl - which I have  
had multicasting beeps to VLC and QuickTime.


nick.


On 20 Feb 2006, at 11:58, Simon Morlat wrote:

> Hi,
>
> Are you incrementing the timestamp by 160 each time ?
> If you want to get the exact buffer for the packet, you can use the
> rtp_session_recvm_with_ts(). It returns you the rtp packet:
>
> while(1){       
>         mblk_t *mp=rtp_session_recvm_with_ts(session, ts);
>         if (mp!=NULL){
>                 //the rtp header is between mp->b_rptr and mp->b_wptr
> 		//the rtp payload is between mp->b_cont->b_rptr and mp->b_cont- 
> >b_wptr
>                 mblk_t *payload=mp->b_cont;
>                 int len=payload->b_wptr-payload->b_rptr;
>                 output_to_sound_device(payload->b_rptr,len);
>         }
>         ts+=160;
> }
>
> Simon
>
> Le Jeudi 16 Février 2006 23:25, Nicholas J Humfrey a écrit :
> > Hi,
> >
> > I have been calling rtp_session_recv_with_ts (with scheduling and
> > blocking mode turned on) with a buffer bigger than I am actually
> > expecting data for.  eg (passing a 1024 byte buffer, when expecting
> > 160 PCMU bytes back).
> >
> > I was expecting to only get enough data for the timestamp I was
> > asking for, but instead it seems to be giving me more data than I was
> > expecting and then later getting confused that it doesn't have enough
> > data for me and dropping out.
> >
> > Is this a bug or a feature?  I was hoping to only have to think about
> > timestamps and like oRTP work out how much data there is available
> > for that timestamp....
> >
> >
> > Thanks,
> >
> > nick.
> >
> >
> >
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