[gst-devel] Compiz Video Performance

Christopher Halse Rogers chalserogers at gmail.com
Thu Dec 4 03:32:49 CET 2008

On Wed, Dec 3, 2008 at 10:17 PM, Colin Guthrie <gmane at colin.guthr.ie> wrote:
> 'Twas brillig, and Murray Blakeman at 03/12/08 10:25 did gyre and gimble:
>> I use Totem/GStreamer for viewing movie files.
>> With Compiz active the picture breaks up, especially in fullscreen.
>> How do I improve/fix the performance of video in Compiz.
>> CPU usage doesn't go beyond 20% but the picture still breaks up (tears)
>> quite often.
>> When I disable Compiz I can view the movies perfectly.
This sounds more like a sync-to-vblank issue rather than one of
decoding/display speed.  Having a composite manager enabled will break
the vsync normally provided for Xv as the video gets rendered to an
offscreen buffer, and it's the composite manager's job to actually
display it.  You might want to check if you can reduce tearing by
enabling sync-to-vblank (ensuring that it has detected the correct
refresh rate) in Compiz' settings.

> AFAIK the video plugin defines a kind of experimental extension to XV.
> The mplayer patch is the only one to take advantage of this.
> I think you'd have to look at what this patch does and then port that
> code to gstreamer.
> I think the intention was to be a bit more "standard" about the
> extension to XV so that wider adoption by other players (gstreamer, xine
> etc.) is promoted. You'd be better asking on the compiz mailing list
> about this tho'.
> There is also nvidias VDPAU "standard" that is in beta now... no idea
> what that means for compositing tho', nor how far outside of nvidia
> chipsets it could spread.

Given that this is the third such standard - Intel introduced one
about 1.5 years ago, ATI introduced one a couple of fglrx releases ago
- I wouldn't hold my breath.

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