title: how to use gstreamer in a qt project on windows?
body: <p><a href="https://gitlab.com/njager/gstreamer-test/tree/master" rel="nofollow noreferrer">Here you can find a qt project to reproduce the problem</a></p>
  
  <p>I need to use <strong>gstreamer</strong> inside a <strong>Qt/Qml</strong> application. I installed <strong>gstreamer-1.0-devel-x86_64-1.14.3</strong> and <strong>gstreamer-1.0-x86_64-1.14.3</strong></p>
  
  <p>For some reason <strong>GST_PLUGIN_PATH</strong> is not set. I set it myself with <code>putenv()</code>.</p>
  
  <p>I got a lot of warnings, see below the first ones,</p>
  
  <pre><code>(gstreamer-test.exe:8540): GStreamer-WARNING **: Failed to load plugin 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\libgsta52dec.dll': 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\libgsta52dec.dll': The specified module could not be found.
  
  (gstreamer-test.exe:8540): GStreamer-WARNING **: Failed to load plugin 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\libgstaccurip.dll': 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\libgstaccurip.dll': The specified module could not be found.
  
  (gstreamer-test.exe:8540): GStreamer-WARNING **: Failed to load plugin 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\libgstadder.dll': 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\libgstadder.dll': The specified module could not be found.
  </code></pre>
  
  <p>In the code I try to make several <code>GstElement</code>,</p>
  
  <pre><code>/* Create gstreamer elements */
  GstElement *pipeline, *source, *demuxer, *decoder, *conv, *sink;
  pipeline = gst_pipeline_new ("audio-player");
  source   = gst_element_factory_make ("filesrc",       "file-source");
  demuxer  = gst_element_factory_make ("oggdemux",      "ogg-demuxer");
  decoder  = gst_element_factory_make ("vorbisdec",     "vorbis-decoder");
  conv     = gst_element_factory_make ("audioconvert",  "converter");
  sink     = gst_element_factory_make ("autoaudiosink", "audio-output");
  </code></pre>
  
  <p>then I check for each <code>GstElement</code> if they was well build. The result show,</p>
  
  <pre><code>source == nullptr
  demuxer == nullptr
  decoder == nullptr
  conv == nullptr
  </code></pre>
  
  <p>wich for example, in the case of <code>source</code> means the <code>factoryname</code> <code>filesrc</code> was not found.</p>
  
  <p>but <code>gst-inspect-1.0.exe</code> found it as show the screenshot,
  <a href="https://i.stack.imgur.com/vD7Pc.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vD7Pc.png" alt="enter image description here"></a></p>
  
  <p>and in the meantime, the <code>factoryname</code> <code>autoaudiosink</code> work.</p>
  
  <p>to finish, I got several criticals messages,</p>
  
  <pre><code>(gstreamer-test.exe:8540): GLib-GObject-CRITICAL **: g_object_set: assertion 'G_IS_OBJECT (object)' failed
  
  (gstreamer-test.exe:8540): GStreamer-CRITICAL **: gst_bin_add: assertion 'GST_IS_ELEMENT (element)' failed
  
  (gstreamer-test.exe:8540): GStreamer-CRITICAL **: gst_element_get_static_pad: assertion 'GST_IS_ELEMENT (element)' failed
  
  (gstreamer-test.exe:8540): GStreamer-CRITICAL **: gst_object_unref: assertion 'object != NULL' failed
  </code></pre>
  
  <p>no clue about why I got them...</p>
  
  <p><em>note: since <a href="https://github.com/GStreamer/qt-gstreamer" rel="nofollow noreferrer">qt-gstreamer</a> is unmaintained I didn't tried it.</em></p>