Re: [Linphone-developers] rtp timestamp for video

[Simon Morlat]

Le Wednesday 19 December 2007 08:12:36 Pramod Bhagwat, vous avez écrit :
> Thanks Simon.  i made one more observation if i increment the user_ts value
> with 240 (like audio timestamp for 30 millisecond) then
> rtp_session_sendm_with_ts() function is taking 26 to 30 millisecond. Does
> this give any hint?
Yes: you don't need blocking mode (use 
rtp_session_set_blocking_mode(session,false);
since your camera is delivering frames on time.
Blocking mode would be required if you would be streaming frames from a file 
for example.


> For streaming the video i have modified the rtpsend application present in
> the tests folder of the ortp. i have registered avprofile
> payload_type_h263_1998 and using payload 96 (dynamic).
>
> Warm Regards,
> pramod
>
> On Dec 14, 2007 3:01 PM, Simon Morlat <address@hidden> wrote:
> > Hi,
> >
> > Usually cameras have approximate frames per second values. Incrementing
> > the
> > timestamp by 90000/30 is not reliable.
> > You should instead do a gettimeofday each time the camera gives you a
> > frame,
> > and then send the packet with a timestamp derived from the gettimeofday
> > time.
> > uint32_t ts=(uint32_t) (current_time_in_milliseconds*90);
> >
> > Simon
> >
> > Le Monday 10 December 2007 13:44:37 Pramod Bhagwat, vous avez écrit:
> > > Hi,
> > > I am using oRTP to stream the video data from the camera on Linux. I am
> > > using H.263 codec  for sending the video data. I am using custom H.263
> > > codec and added the H.263 header packetization  routines using
> > > rtp_session_create_packet() function and then sending the data using
> > > rtp_session_sendm_with_ts() function.
> > > Here I am incrementing "user_ts" value by 3000 Since the Camera outputs
> >
> > 30
> >
> > > frames per second.
> > > i.e. 90000/30 = 3000.
> > > But when i profiled the rtp_session_sendm_with_ts() function using
> > > gettimeofday it is taking 400 millisecond which is very large value.
> > >
> > > Is there any thing wrong in my timestamp calculation. Please let me
> >
> > know.
> >
> > > Warm Regards,
> > > pramod