title: Compiling Opencv with Gstreamer, cmake not finding GStreamer
body: <p>I want to build opencv with GStreamer support.</p>
  
  <p>I built the GStreamer from source (version 1.8.1) following this guide:
  <a href="http://kacianka.at/?p=145" rel="noreferrer">http://kacianka.at/?p=145</a>
  I have 'gstreamer_build' folder at my home directory and it contains 'bin' folder with these:</p>
  
  <blockquote>
    <p>gst-device-monitor-1.0 
    gst-discoverer-1.0  gst-inspect-1.0 
    gst-launch-1.0  gst-play-1.0 
    gst-stats-1.0  gst-typefind-1.0 
    orc-bugreport  orcc</p>
  </blockquote>
  
  <p>I have this path added to my environment variable PATH.</p>
  
  <p>When I use cmake like:</p>
  
  <blockquote>
    <p>cmake -D CMAKE_BUILD_TYPE=RELEASE -D
    CMAKE_INSTALL_PREFIX=/usr/local -D
    OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules -D BUILD_opencv_python3=ON -D WITH_GSTREAMER=ON -D WITH_FFMPEG=OFF
    ..</p>
  </blockquote>
  
  <p>I get the following output clearly indicating that gstreamer is not found:</p>
  
  <pre><code>-- checking for module 'gstreamer-base-1.0'
  --   package 'gstreamer-base-1.0' not found
  -- checking for module 'gstreamer-video-1.0'
  --   package 'gstreamer-video-1.0' not found
  -- checking for module 'gstreamer-app-1.0'
  --   package 'gstreamer-app-1.0' not found
  -- checking for module 'gstreamer-riff-1.0'
  --   package 'gstreamer-riff-1.0' not found
  -- checking for module 'gstreamer-pbutils-1.0'
  --   package 'gstreamer-pbutils-1.0' not found
  -- checking for module 'gstreamer-base-0.10'
  --   package 'gstreamer-base-0.10' not found
  -- checking for module 'gstreamer-video-0.10'
  --   package 'gstreamer-video-0.10' not found
  -- checking for module 'gstreamer-app-0.10'
  --   package 'gstreamer-app-0.10' not found
  -- checking for module 'gstreamer-riff-0.10'
  --   package 'gstreamer-riff-0.10' not found
  -- checking for module 'gstreamer-pbutils-0.10'
  --   package 'gstreamer-pbutils-0.10' not found
  </code></pre>
  
  <p>and this:</p>
  
  <pre><code>Video I/O:
  --     DC1394 1.x:                  NO
  --     DC1394 2.x:                  NO
  --     FFMPEG:                      NO
  --       codec:                     NO
  --       format:                    NO
  --       util:                      NO
  --       swscale:                   NO
  --       resample:                  NO
  --       gentoo-style:              NO
  --     GStreamer:                   NO
  --     OpenNI:                      NO
  --     OpenNI PrimeSensor Modules:  NO
  --     OpenNI2:                     NO
  --     PvAPI:                       NO
  --     GigEVisionSDK:               NO
  --     UniCap:                      NO
  --     UniCap ucil:                 NO
  --     V4L/V4L2:                    Using libv4l1 (ver 1.0.1) / libv4l2 (ver 1.0.1)
  --     XIMEA:                       NO
  --     Xine:                        NO
  --     gPhoto2:                     NO
  </code></pre>
  
  <p>Can anyone help me with this?</p>