[gst-devel] why this pipeline doesnot work

[Jerry tan]

hi, guys,

gst-launch videotestsrc ! ximagesink  works on my system,
but gst-launch videotestsrc !* *ffmpegcolorspace* ! * ximagesink does 
not work

it tells me that
ERROR: Pipeline doesn't want to pause.
ERROR: from element /pipeline0/videotestsrc0: Could not negotiate format
Additional debug info:
gstbasesrc.c(1790): gst_base_src_start (): /pipeline0/videotestsrc0:
Check your filtered caps, if any


how could I fix this problem?
I am running it on sunray client