[gst-devel] xml pipeline run problem

kpykcb at gmail.com kpykcb at gmail.com
Tue Jun 16 07:48:17 CEST 2009

Hi everyone, i have C code that realize this pipeline: 

gst-launch v4l2src ! video/x-raw-yuv,width=320,height=240 !
ffmpegcolorspace ! jpegenc ! udpsink host=localhost port=5000

After construction of pipeline i save it to xml file:

gst_xml_write_file (GST_ELEMENT (pipeline), fopen ("gstcam-xml.gst",

Then when i try to run this pipeline 
>>with python code (IPython) 

>In [6]: xml.parse_file("gstcam-xml.gst", "r")
(ipython:3958): GStreamer-CRITICAL **: gst_pad_link: assertion
`GST_PAD_IS_SRC (srcpad)' failed Out[6]: True

>or just
pycli> gst-xmllaunch gstcam-xml.gst 

(gst-launch-0.10:3953): GStreamer-CRITICAL **: gst_pad_link: assertion
`GST_PAD_IS_SRC (srcpad)' failed Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
ERROR: from element /GstPipeline:v4l2src udp server/GstV4l2Src:cam
reader: Internal data flow error. Additional debug info:
gstbasesrc.c(2334): gst_base_src_loop (): /GstPipeline:v4l2src udp
server/GstV4l2Src:cam reader: streaming task paused, reason
not-negotiated (-4) Execution ended after 1243745015 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
FREEING pipeline ...

>and finaly with compiled example from "Gst app dev manual" 

(xmlload:4050): GStreamer-CRITICAL **: gst_pad_link: assertion
`GST_PAD_IS_SRC (srcpad)' failed **
ERROR:xmlload.c:20:main: assertion failed: (pipeline != NULL)

I have such error. I'm newbie with gstreamer that's why does not fully
understand error message cause. One assumption is wrong generation of
xml code(its quite long, so i mail it if needed separately)

I dont sink that it is some Debian-specific error, but:
my box is: Debian Lenny + some Testing and Unstable packages, uvc
webcam, particulary i have eee-pc 901.
pycli> dpkg -l | gr gst
ii  gstreamer-tools                      0.10.19-3
Tools for use with GStreamer ii  gstreamer0.10-alsa
0.10.23-2                     GStreamer plugin for ALSA ii
gstreamer0.10-ffmpeg                 0.10.4-3
FFmpeg plugin for GStreamer ii  gstreamer0.10-fluendo-mp3
0.10.7.debian-1               Fluendo mp3 decoder GStreamer plugin ii
gstreamer0.10-fluendo-mpegdemux      0.10.15-1
GStreamer plugin for demuxing of MPEG2 streams ii
gstreamer0.10-fluendo-mpegmux        0.10.4-1
GStreamer plugin for muxing of MPEG2 TS streams ii
GStreamer plugin for using MS Windows binary codecs ii
gstreamer0.10-plugins-base           0.10.23-2
GStreamer plugins from the "base" set ii
gstreamer0.10-plugins-base-apps      0.10.19-2
GStreamer helper programs from the "base" set ii
gstreamer0.10-plugins-good           0.10.8-4.1~lenny1
GStreamer plugins from the "good" set ii
gstreamer0.10-plugins-ugly           0.10.8-1
GStreamer plugins from the "ugly" set ii
gstreamer0.10-tools                  0.10.19-3
Tools for use with GStreamer ii  gstreamer0.10-x
0.10.19-2                     GStreamer plugins for X11 and Pango ii
libgstreamer-plugins-base0.10-0      0.10.23-2
GStreamer libraries from the "base" set ii
libgstreamer0.10-0                   0.10.23-1                     Core
GStreamer libraries and elements ii
libgstreamer0.10-dev                 0.10.23-1
GStreamer core development files ii
python-gst0.10                       0.10.12-1.1
generic media-playing framework (Python bindings)

WBR Lavruschenko Oleksandr

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