title: gst_parse_launch differs output from command line gst_launch
body: <p>I have a pipeline like this, which works with gst-launch-1.0</p>
  
  <pre><code>gst-launch-1.0 v4l2src device='/dev/video0' ! 'video/x-raw,format=(string)YUY2,width=(int)640,height=(int)480' ! nvvidconv ! 'video/x-raw(memory:NVMM),format=(string)NV12,width=(int)640,height=(int)480' ! nvvidconv ! 'video/x-raw,format=(string)NV12,width=(int)640,height=(int)480' ! nvvideoconvert ! 'video/x-raw(memory:NVMM),format=(string)NV12,width=(int)640,height=(int)480' ! mux.sink_0 nvstreammux live-source=1 name=mux batch-size=1 width=640 height=480 ! nvinfer config-file-path=/opt/nvidia/deepstream/deepstream-4.0/sources/apps/sample_apps/deepstream-test1/dstest1_pgie_config.txt batch-size=1 ! nvmultistreamtiler rows=1 columns=1 width=640 height=480 ! nvvideoconvert ! nvdsosd ! nvegltransform ! nveglglessink sync=false -v
  
  </code></pre>
  
  <p>In my c application, such as below which executes the same command line, it doesn't display any window. </p>
  
  <pre><code>#include &lt;gst/gst.h&gt;
  
  int
  main (int argc, char *argv[])
  {
    GstElement *pipeline;
    GstBus *bus;
    GstMessage *msg;
  
    /* Initialize GStreamer */
    gst_init (&amp;argc, &amp;argv);
  
    /* Build the pipeline */
    pipeline =
        gst_parse_launch
        ("v4l2src device='/dev/video0' ! 'video/x-raw,format=(string)YUY2,width=(int)640,height=(int)480' ! nvvidconv ! 'video/x-raw(memory:NVMM),format=(string)NV12,width=(int)640,height=(int)480' ! nvvidconv ! 'video/x-raw,format=(string)NV12,width=(int)640,height=(int)480' ! nvvideoconvert ! 'video/x-raw(memory:NVMM),format=(string)NV12,width=(int)640,height=(int)480' ! mux.sink_0 nvstreammux live-source=1 name=mux batch-size=1 width=640 height=480 ! nvinfer config-file-path=/opt/nvidia/deepstream/deepstream-4.0/sources/apps/sample_apps/deepstream-test1/dstest1_pgie_config.txt batch-size=1 ! nvmultistreamtiler rows=1 columns=1 width=640 height=480 ! nvvideoconvert ! nvdsosd ! nvegltransform ! nveglglessink sync=false -v",
        NULL);
  
    /* Start playing */
    gst_element_set_state (pipeline, GST_STATE_PLAYING);
  
    /* Wait until error or EOS */
    bus = gst_element_get_bus (pipeline);
    msg =
        gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE,
        GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
  
    /* Free resources */
    if (msg != NULL)
      gst_message_unref (msg);
    gst_object_unref (bus);
    gst_element_set_state (pipeline, GST_STATE_NULL);
    gst_object_unref (pipeline);
    return 0;
  }
  
  </code></pre>