Use sdp in order to playback rtp stream

[Paixao Julien]

> -----Original Message-----
> From: gstreamer-devel [mailto:gstreamer-devel-bounces at lists.freedesktop.org] On Behalf Of Sebastian Dröge
> Sent: Tuesday, May 03, 2016 9:25 AM
> To: Discussion of the development of and with GStreamer <gstreamer-devel at lists.freedesktop.org>
> Subject: Re: Use sdp in order to playback rtp stream
> 
> On Di, 2016-05-03 at 07:18 +0000, Paixao Julien wrote:
> >
> > > Can you show an example SDP? This means that it's not detected as
> > > SDP by GStreamer for whatever reason.
> > >
> > v=0
> > o=user 53655765 2353687637 IN IP4 10.20.1.250
> > s=-
> > c=IN IP4 10.20.1.39
> > t=0 0
> > m=audio 3001 RTP/AVP 0
> > a=rtpmap:0 PCMU/8000
> 
> Which version of GStreamer are you using? 1.8.1 is detecting this as valid SDP.
> 

I caught it, something "stupid" the typefindfunctions plugin was not installed...
Now it's correctly detected.

> > > > On client side, I also tried the sdpdemux element, but the problem
> > > > with that element is that it "only" provides the RTP raw data, but
> > > no information about the media stream properties (G711 or G722).
> > > >
> > > > So I cannot know which rtp depayloader to attach to the rtp raw
> > > > data...
> > > >
> > > > Would you know a way of achieving the needed playback of such an
> > > > RTP stream containing G711 or G722?
> > > The application/x-rtp caps on the streams that come out of sdpdemux
> > > have all the relevant information from the SDP, including the
> > > encoding name.
> > >
> > Indeed, it should do the job, I will attach the correct rtp
> > depayloader and decoder depending on the caps in the application/x-
> > rtp of the stream.
> 
> You can also use decodebin for example, it will automatically pick a depayloader for you based on the caps.
> 

Indeed, it's much better, it works nicely.

> > FYI I am now trying to get it working with a multicast IP in the SDP. For the moment I get an error, I will dig into it (no bug report
> found).
> > ERROR: from element /GstPipeline:pipeline0/GstSDPDemux:sdpdemux0/GstUDPSrc:udpsrc0: Could not get/set settings from/on
> resource.
> > Additional debug info:
> > gstudpsrc.c(916): gst_udpsrc_start (): /GstPipeline:pipeline0/GstSDPDemux:sdpdemux0/GstUDPSrc:udpsrc0:
> > could add membership: Error joining multicast group: No such device
> 
> Can you file a bug about this with the SDP and a debug log with GST_DEBUG=udpsrc:6? Do you have multiple network devices and a
> specific one has to be used for this multicast group?
> 

I have only one network device and only one interface (which is on a linux machine eth0).
I just created a bug report, please find it on the following link https://bugzilla.gnome.org/show_bug.cgi?id=765925

BTW do you know of a good decoder for G722? I searched and found one in ffmpeg, would it not be nicer to have elements similar to G711 and G722?
e.g g722depayloader & g722decoder

Best regards,
Julien.