|| Antonio Trande on 2013-07-02 17:38
|| Priority: Normal
|| Affected: branch '2.4'
|| Category: highgui-video
|| Tracker: Bug
|| Difficulty: Medium
|| PR: 
|| Platform: x64 / Linux

Hi all.

This warning appears when I try to load a video file in 'qgifer' software (http://sourceforge.net/projects/qgifer/) in Fedora 19 with opencv-2.4.5 installed:

<pre>
$ qgifer
ffmpeg version 1.2.1
built on Jun 21 2013 12:33:57 with gcc 4.8.1 (GCC) 20130603 (Red Hat 4.8.1-1)
configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic' --enable-bzlib --disable-crystalhd --enable-frei0r --enable-gnutls --enable-libass --enable-libcelt --enable-libdc1394 --disable-indev=jack --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-openal --enable-libopencv --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvpx --enable-libx264 --enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
libavutil      52. 18.100 / 52. 18.100
libavcodec     54. 92.100 / 54. 92.100
libavformat    54. 63.104 / 54. 63.104
libavdevice    54.  3.103 / 54.  3.103
libavfilter     3. 42.103 /  3. 42.103
libswscale      2.  2.100 /  2.  2.100
libswresample   0. 17.102 /  0. 17.102
libpostproc    52.  2.100 / 52.  2.100
FramePlayer::openSource new video loaded:  "/home/sagitter/Videos/big_buck_bunny.ogv" 
codec name:  "" 
warning: GStreamer: unable to query position of stream (/builddir/build/BUILD/opencv-2.4.5/modules/highgui/src/cap_gstreamer.cpp:660)
total frames:  0 
dragging B 
preview destroyed...
</pre> 

I don't know if it is related to opencv or not.

-   Assignee set to Alexander Smorkalov

The code that generates warning is:
    case CV_CAP_PROP_FRAME_COUNT:
        format = GST_FORMAT_DEFAULT;
        if(!gst_element_query_duration(pipeline, &format, &value)) {
            CV_WARN("GStreamer: unable to query position of stream");
            return false;
        }

This warning looks like some GStreamer issue. Try to update GStreamer and install appropriate plug-ins for it.
I cancel the ticket.
-   Status changed from New to Cancelled

Hi Alexander.

> This warning looks like some GStreamer issue.

Well, GStreamer maintainer says that this problem is outside of GStreamer: [https://bugzilla.gnome.org/show_bug.cgi?id=703632#c1] :) 
The code you are showed is in 'opencv-2.4.5/modules/highgui/src/cap_gstreamer.cpp' file; do you think may be a conflict between GStreamer-0.10 and GStreamer-1.0 ?

As I know, GStreamer 1.0 is incompatible with 0.1. It can case problem here.
-   Status changed from Cancelled to Open

Alexander Smorkalov wrote:
> As I know, GStreamer 1.0 is incompatible with 0.1. It can case problem here.

This is a big problem because in Fedora 19 Gnome-based gstreamer-1.0 is a main dependency of Gnome. If I try to remove gstreamer-1.0 and leave just old gstreamer-0.10, the package manager removes various main packages (Gnome-shell, Nautilus, GDM, ...).

The GStreamer warning in question appears by using other applications related with opencv, too.

I reproduce your issue with OpenCV laplace example.
GStreamer version: 0.10.36
OS: OpenSuse Linux 12.2
-   Affected version changed from 2.4.0 - 2.4.5 to branch '2.4'
-   Difficulty set to Medium
-   Category set to highgui-video

-   Target version set to Next Hackathon