Still can't get videomixer to do live video at full frame rate

[Josh Doe]

On Tue, Aug 16, 2011 at 5:03 PM, wally bkg <wb666greene at gmail.com> wrote:
>
> Trying to display two genlocked camera images from two v4l2 capture devices
> in a single frame, ultimately to an appsink.
>
> This pipeline works but can't get full frame rate :(
>
> gst-launch v4l2src device=/dev/video0 ! queue ! \
> video/x-raw-yuv,format =\(fourcc\)I420, framerate=\(fraction\)30000/1001,
> width=640, height=480 ! \
> videomixer name=mix sink_0::alpha=1.0 sink_0::xpos=0 sink_0::ypos=0
> sink_1::alpha=1.0 sink_1::xpos=0 sink_1::ypos=480  \
> sink_2::zorder=3  !   xvimagesink \
> v4l2src device=/dev/video1 ! queue ! video/x-raw-yuv,format=\(fourcc\)I420,
> framerate=\(fraction\)30000/1001, width=640, height=480 ! mix. \
> videotestsrc pattern=2 ! queue ! video/x-raw-yuv,format=\(fourcc\)I420,
> framerate=\(fraction\)1/1, width=640, height=960 ! mix.

I'm not sure what's wrong with this pipeline, it's almost identical to
one I've used without problem.

> [...]
>
> Occasionally the videomixer gst-launch command spits out (not often, but I
> saw it this time and its why I'm posting this) a warning message:
>
> WARNING: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: A
> lot of buffers are being dropped.
> Additional debug info:
> gstbasesink.c(2597): gst_base_sink_is_too_late ():
> /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0:
> There may be a timestamping problem, or this computer is too slow.
>
>
> What is a timestamping problem and what can I do about it?

It's not likely a timestamping problem, but rather your
system/pipeline can't keep up. You can ignore this, increase the
time/frames/size of your queue's, or maybe set sync=false to
xvimagesink.

-Josh