Am Mittwoch 20 Oktober 2010, um 22:20:13 schrieb Damien Lespiau:
> On Wed, 2010-10-20 at 20:28 +0100, Lukas Ruetz wrote:
> > Hello,
> 
> Hi,
> 
> > I have a performance/sync problem when playing raw YUV or DV video. I've
> > invested many days now and can't find a solution.
> > The playback is fine with gstreamer alone (with glimagesink and VBLANK by
> > the graphics driver), but in clutter it's stuttering.
> > 
> > The real strange thing is that it sometimes plays without any problem,
> > and sometimes not. I've made this experience on different systems. These
> > systems always have < 30% CPU load and 2-4 cores.
> > 
> > This behaviour is also reproduceable with the example video-player from
> > clutter-gst so the problem isn't in my code. Some runs are ok, some not.
> > 
> > Could this be a sync problem between the two frameworks - gstreamer with
> > it's framerate - clutter with the VBLANK (which is turend on)?
> > Clutter reports FPS between 25-26 - does this mean it's a bit too fast or
> > is this measurement just not so exact?
> > 
> > The source (in this case a DV video in PAL size) was once decoded to YUY2
> > (and then to I420) but also to RGB - with no difference.
> > 
> > Any thoughts?
> 
> So, I've grabbed a USB webcam and hacked tests/test-yuv-upload.c to use
> v4l2src and I can't reproduce that behaviour at all. Every time I launch
> the test, it works (and I test it with the same clutter/clutter-gst
> versions as you).
> 
> Have you tried to add a queue to decouple a bit the pipeline?

Hi, 

sorry for my late answer. Yes I have a queue in my pipeline. The problem is 
only visible during a lot of motion in the picture so it's not really obvious.

Now I've tried another hardware where the V4L playback is ok, but it's 
stuttering again when there are other translucent actors (2-5 non-moving
static images) on the stage above the video covering about 1/5 of the area.
Having the same overlay on a ~7Mbit H.264 videos works. The raw YUV video
from a v4l-source is much more simpler video (without audio) but of course
with a lot more data (720px * 576px * 12bpp * 25fps = ~124Mbit/s). Maybe
this is the problem? I'll keep on trying ..

thanks
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