[gst-devel] Changing video effects while playing using pad blocking

Luciana Fujii Pontello luciana at holoscopio.com
Fri Feb 12 19:37:57 CET 2010


I'm trying to apply effects to a video and change these effects while
streaming. Someone suggested that I use pad blocking, and so I'm trying
to using mostly this as my information font:

Using this code http://codepad.org/JqSs1DFn to change elements I usually
can change effects while streaming, but sometimes the pipeline just
stops. In fact, it always stops when I change to an yuv effect from a
rgb effect or vice-versa, and sometimes it stops with effects of the
same type (but not exactly the same caps).

I can apply, for instance, videoflip, and then navigationtest. But if I
change to vertigotv next, the pipeline stops.

I also asked about that and someone told me that the elements should
handle this change in colorspace and that some element could be broken.
The only elements I'm using right now are:
v4l2src ! ffmpegcolorspace ! queue ! effect ! ffmpegcolorspace !
autovideosink. My test aplication can be found in

I really don't know where to look now. I'm not sure I'm changing the
elements correctly, or if it is something with the elements I'm using.
Can anyone point me a way? Maybe an example of pad blocking that can do
something similar to what I'm doing?


Luciana Fujii
Holoscópio Tecnologia - http://holoscopio.com

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