[MPlayer-users] UDP -udp-slave video sync

[Reimar Döffinger]

On Wed, Jun 08, 2011 at 09:46:07PM +0100, Rob Canning wrote:
> Reimar Döffinger wrote:
> >On Wed, Jun 08, 2011 at 02:40:57PM +0100, rob at goto10.org wrote:
> >>ok great thank you! - i applied the patch and now it works as
> >>expected
> >
> >Unfortunately I couldn't see the patch. However the behaviour
> >was due to a stupid bug I introduced, and that happened because
> >with vsync enabled the video I tested actually did run at about
> >correct speed so the behaviour wasn't as bad as what you experienced.
> >Assuming it really works this time, the change in SVN should have
> is this a recent change in the SVN - should i update and recompile it ?

Yes.

> >the advantage that the slave instances will start playing independently
> >after 30 seconds.
> >
> does this mean after 30 seconds of being synced then the independent
> playback will kick in and the audio/video sync lag will be able to
> rectify itself?

No, it means after the network being down for 30 seconds or the master
having died unexpectedly or whatever the slaves start playing
normally, waiting for the master to become available again.

> >>(i know if i were doing a video wall then you could just use the
> >>audio from one source - but this is not what i am doing)
> >
> >Might help to say what you are doing. You can certainly just
> >set up an audio server and transmit the audio to the slaves via
> >network, independent of the MPlayer slaves.
> ok so i have 8 computers each playing a 720HD mkv file with 5.1
> sound - each playback computer needs to have the video and 5.1 in
> sync and each of the 8 computers also in sync - the material on each
> of the playback computers is different but of equal duration - the
> udp master slave thing seemed like it might be a solution but the
> lack of absolute sync between the audio and video within each
> machine is a problem
> any suggestions on how to make this happen would be most appreciated

What is the duration? How precisely must it be in sync?
In principle it is possible to change playback speed dynamically
(which in case of -udp-slave would only affect audio) but it's
not implemented yet to do that based on UDP sync or something
and I'm not sure it's a good idea anyway since it decreases audio
quality and introduces jitter even with a good implementation.