[gst-devel] stuck with looping videos into a mixer

Luis de Bethencourt luisbg at ubuntu.com
Thu Jun 5 17:01:44 CEST 2008

Hello everybody,

For the last week I've been coding a video application, small doubts
and little fixes have been done through irc, thanks wtay and thanks
thaytan (you rock!). Anyway, now I stuck. My application switchs
videos that loop, its a vj app.

You can check:

In the solo folder... I have a bin.py where the video bin is created,
this bin overrides the do_handle_message virtual method to capture
when the segment is done and do a seek to start the video again. This
bin is fed to a xvimagesink.... it works perfectly.

In the mix_1 folder... I have the same bin.py, feeding to a videomix
and this to the image sink. Also works perfectly.

In the mix_2 folder is where the problems start, when looping two
videos into the mixer... strange things happen, I would report the
outcome if it werent that everytime I run it a different thing
happens. But usually the shorter video loops, and when the second
finishes they both stall... or they both stall after the short one
finishes. Or the short one finishes and then only the long one is
played at high speed. Or they will pause, then continue, pause, then

I need help! :(

This solution for a vj app problem has been thought because if I do a
pipeline with only one videosource, when I stop this, to change the
file source, to play again. The stopping, decoding, negotiating,
etc... makes a black frame in each switch, and this isnt good.
Switches in a vj gig, usually happen every few beats of a song, so a
lot of them per minute.

Plus it would be nice in the future to do fades for the switches...
but I dont care about that yet, first I need seamless direct switch.

Any ideas? Any help?

Luis de Bethencourt

pd: I'm running CVS version of gstreamer (Jan told me there has been
fixes in the videomixer lately)

Luis de Bethencourt Guimerá
<luisbg at ubuntu.com>
GPG: B0ED1326

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