frei0r-filter-perspective parameters? Found them but internal dataflow error

Jos van Riswick josvanr at
Tue Jun 7 00:11:36 PDT 2011

trying this:

gst-launch v4l2src ! video/x-raw-yuv,width=320,height=240 !
ffmpegcolorspace !
! xvimagesink

ie view webcam and remove perspective distortion

First it complains it cannot find a file
but turns out to be an installation problem. After I get this from
some package however:...

reason not negotiated?


Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
Internal data flow error.
Additional debug info:
gstbasesrc.c(2574): gst_base_src_loop ():
streaming task paused, reason not-negotiated (-4)
Execution ended after 2507571638 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...

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