synchronising multiple audio clients

[Johannes Bauer]

Hello!

Thanks for your reply!
Your talk is really informative and i think I understood a lot of those
parameters much better now.

In my understanding I need to distribute a common GstClock in order to have
the clients synchronised.

As I understand, the gst_net_clock needs to be requested by every client
and cannot be received via multicast.
So there is a lot of network traffic if every clients request clock info
from the server.
Is there a way to distribute the clock via multicast?

Kind regards
JB


2016-07-08 12:34 GMT+02:00 Sebastian Dröge <sebastian at centricular.com>:

> On Fr, 2016-07-08 at 12:21 +0200, Johannes Bauer wrote:
> > Hello!
> >
> > Since I had problems getting gst-python running i wrote my programs
> > in C for both serer and client.
> > I now have GStreamer 1.8.1 on my server (Win7) and also on both of my
> > clients (raspi2 with wheezy and raspi3 with jessy).
> >
> > My server starts streaming an mpa stream from the mic input to the
> > clients via rtp and rtcp multicast. The clients receive the rtp
> > stream and the rtcp data.
> >
> > I hear the output on both of my raspberries, however raspi2 is about
> > 0.5 seconds delayed in contrast to the raspi3.
> >
> > Is it possible to synchronize them, so there is "no" delay among the
> > clients?
> >
> > I read something about the rtpbin parameters ntp-time-source, ntp-
> > sync, latency, buffer-mode and tried to play around with them, but i
> > can't manage to get the clients synchronised. Is it possible with the
> > properties or do i need to do something else here?
>
> The easiest solution would be by using gst-rtsp-server and sharing a
> clock between the different clients:
>
> https://cgit.freedesktop.org/gstreamer/gst-rtsp-server/tree/examples/test-netclock-client.c
>
> https://cgit.freedesktop.org/gstreamer/gst-rtsp-server/tree/examples/test-netclock.c
>
> But you can of course also implement the same manually without RTSP.
>
> See also my talk at the GStreamer conference about this:
>
> https://gstconf.ubicast.tv/videos/synchronised-multi-room-media-playback-and-distributed-live-media-processing-and-mixing-with-gstreamer/
>
> --
>
> Sebastian Dröge, Centricular Ltd · http://www.centricular.com
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