title: gstreamer pipeline to show images
body: <p>i use videomixer to display multiplr images in one windows i use the following code to do it</p>
  
  <pre><code>#include &lt;gst/gst.h&gt; 
  #include &lt;glib.h&gt;
  
  
  
  
  static gboolean bus_call (GstBus     *bus,
                            GstMessage *msg,
                            gpointer    data)
  {
    GMainLoop *loop = (GMainLoop *) data;
  
    switch (GST_MESSAGE_TYPE (msg)) {
  
     case GST_MESSAGE_EOS:
        g_print ("End of stream\n");
        g_main_loop_quit (loop);
        break;
      case GST_MESSAGE_ERROR: {
        gchar  *debug;
        GError *error;
  
        gst_message_parse_error (msg, &amp;error, &amp;debug);
        g_free (debug);
  
        g_printerr ("Error: %s\n", error-&gt;message);
        g_error_free (error);
  
        g_main_loop_quit (loop);
        break;
      }
      default:
        break;
    }
    return TRUE;
  }
  
  static void
  on_pad_added (GstElement *element,
                GstPad     *pad,
                gpointer    data)
  {
    GstPad *sinkpad;
    GstElement *decoder = (GstElement *) data;
  
    /* We can now link this pad with the vorbis-decoder sink pad */
    g_print ("Dynamic pad created, linking demuxer/decoder\n");
  
    sinkpad = gst_element_get_static_pad (decoder, "sink");
  
    gst_pad_link (pad, sinkpad);
    gst_object_unref (sinkpad);
  }
  
  int
  main (int   argc,
        char *argv[]) {
  
  GMainLoop *loop;
  
  GstElement *pipeline,*freeze,*clrspace;
  GstElement *source1;
  GstElement *source2;
  GstElement *videobox1,*videobox2;
  GstElement *mixer,*sink,*queuevideo;
  GstBus *bus;
  
  loop = g_main_loop_new (NULL, FALSE);
  
  /* Create gstreamer elements */
  pipeline = gst_pipeline_new ("player");
  source1  = gst_element_factory_make ("playbin2", "dec1");
  source2  = gst_element_factory_make ("playbin2", "dec2");
  freeze = gst_element_factory_make ("imagefreeze", "fr");
  //videobox1 = gst_element_factory_make ("videobox",       "videobox1");
  //videobox2 = gst_element_factory_make ("videobox",       "videobox2");
  clrspace  = gst_element_factory_make ("ffmpegcolorspace",       "clrspace");
  mixer = gst_element_factory_make ("videomixer",       "mixer");
  queuevideo = gst_element_factory_make ("queue", "queue-video");
  sink     = gst_element_factory_make ("xvimagesink", "sink");
  
  
  if (!pipeline || !source1 || !source2 || !sink || !mixer ||!freeze || !clrspace || !queuevideo ) {
      g_printerr ("One element could not be created. Exiting.\n");
      exit(1);
  }
  
  g_object_set (source1, "uri", "http://www.logotheque.fr/6396-2/logo+RMC+INFO.jpg", NULL);
  g_object_set (source2, "uri", "http://www.logotheque.fr/6396-2/logo+RMC+INFO.jpg", NULL);
  
  // g_object_set(videobox1,"border-alpha",0,"top",0,"left",0,NULL);
  // g_object_set(videobox2,"border-alpha",0,"top",0,"left",-200,NULL);
  
  /* we add a message handler */
  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
  gst_bus_add_watch (bus, bus_call, loop);
  gst_object_unref (bus);
  
  /* we add all elements into the pipeline */
  gst_bin_add_many (GST_BIN (pipeline),
                    source1,mixer, clrspace, freeze, sink, source2, NULL);
  
  /* we link the elements together */
  gst_element_link_many (source1, mixer, clrspace, freeze,sink,source2, NULL);
  //gst_element_link_many (source[1], mixer, NULL);
  
   g_signal_connect (source1, "pad-added", G_CALLBACK (on_pad_added), queuevideo);
   g_signal_connect (source2, "pad-added", G_CALLBACK (on_pad_added), queuevideo);
  
  
  /* Set the pipeline to "playing" state*/
  gst_element_set_state (pipeline, GST_STATE_PLAYING);
  
  /* Iterate */
  g_print ("Running...\n");
  g_main_loop_run (loop);
  
  /* Out of the main loop, clean up nicely */
  g_print ("Returned, stopping playback\n");
  gst_element_set_state (pipeline, GST_STATE_NULL);
  
  g_print ("Deleting pipeline\n");
  gst_object_unref (GST_OBJECT (pipeline));
  }
  </code></pre>
  
  <p>i don't have a errors compilation but when i run it  i  show nothing and i have a following warning</p>
  
  <pre><code>(process:5959): GStreamer-CRITICAL **: gst_element_factory_make: assertion `gst_is_initialized ()' failed
  
  (process:5959): GStreamer-CRITICAL **: gst_element_factory_make: assertion `gst_is_initialized ()' failed
  
  (process:5959): GStreamer-CRITICAL **: gst_element_factory_make: assertion `gst_is_initialized ()' failed
  
  (process:5959): GStreamer-CRITICAL **: gst_element_factory_make: assertion `gst_is_initialized ()' failed
  
  (process:5959): GStreamer-CRITICAL **: gst_element_factory_make: assertion `gst_is_initialized ()' failed
  
  (process:5959): GStreamer-CRITICAL **: gst_element_factory_make: assertion `gst_is_initialized ()' failed
  
  (process:5959): GStreamer-CRITICAL **: gst_element_factory_make: assertion `gst_is_initialized ()' failed
  
  (process:5959): GStreamer-CRITICAL **: gst_element_factory_make: assertion `gst_is_initialized ()' failed
  One element could not be created. Exiting.
  </code></pre>
  
  <p>someone can help me please?</p>