H.264 Webcam using uvch264_src

[David Röthlisberger]

On 3 Jan 2013, at 10:19, Thomas Lindner wrote:
> Hello,
> 
> I'm testing the Logitech BCC950 Cam which supports H.264 encoding. The H.264
> encoding should be fully compatible with the C920.
> And in fact, the test tool test-uvch264 works perfect with this cam.
> But when I try to setup the capture-decode-chain thru gst-launch, I always
> get the following *error message*:
> 
> linux-zn8k:~ # gst-launch uvch264_src device=/dev/video1 name=src
> auto-start=true src.vidsrc ! queue !
> video/x-h264,width=1280,height=720,framerate=15/1,profile=constrained-baseline
> ! h264parse ! ffdec_h264
> Setting pipeline to PAUSED ...
> Pipeline is live and does not need PREROLL ...
> Setting pipeline to PLAYING ...
> New clock: GstSystemClock
> *ERROR: from element
> /GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0: Internal data
> flow error.
> Additional debug info:
> gstbasesrc.c(2633): gst_base_src_loop ():
> /GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0:
> streaming task paused, reason not-linked (-1)*

Have you had a look at the debug output for the element causing you
trouble? Look at the man page for gst-launch-0.10, specifically
--gst-debug-level, --gst-debug and --gst-debug-help.

Judging from the output you posted, your uvch264_src is some kind of
"bin" that contains a v4l2src element, so you'd want to enable debug
for your uvch264_src *and* v4l2src, at least.

Hope this helps,
Dave.