[gst-devel] dvdec performance

Louis Bouchard lbouchard at sat.qc.ca
Thu Nov 10 09:50:50 CET 2005

Did anyone have much success in using the dvdec plugin in conjunction
with dv1394src?

For example, if launch the following pipeline:
gst-launch-0.8 dv1394src ! dvdec ! xvimagesink

... I get very poor frame rate, about 8-9 fps.  Also the stream is
displayed slower than real time.  It seems the images are buffered
somewhere and displayed one by one as soon as they get decoded - the
image decoded at any moment is NOT the last frame  sent by the camera.
 Also, at every 50 frames or so, the frames seem to be dropped at an
alarming rate: I figured that since it can't process the stream of
images in real time, it accumulates images until it can't hold any
more and drops them.

I have had some success in dealing with the dropped frames by setting
the drop-factor to 2:
gst-launch-0.8 dv1394src ! dvdec drop-factor=2 ! xvimagesink

it works, the images are played somewhat real-time (with a delay of
about 2 seconds) but the frame rate is still horrible at 8-9 fps.

I have head somewhere that libdv would be the performance culprit, so
I tried installing the latest version but the results are the same.

Has anyone been able to get more performance out of this setup?

I am building my own small app to do this and I am running into the
same problems that I have with gst-launch, so any solution would
probably work for both.

I use Ubuntu (hoary hedgehog) on AMD64.

thanks in advance,

Louis Bouchard

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