change state of pipeline to NULL before freeing.

modules/highgui/src/cap_gstreamer.cpp

@@ -347,12 +347,12 @@ bool CvCapture_GStreamer::open( int type, const char* filename )
     if(!uridecodebin) {
         uridecodebin = gst_element_factory_make ("uridecodebin", NULL);
         g_object_set(G_OBJECT(uridecodebin),"uri",uri, NULL);
-    }
         if(!uridecodebin) {
             CV_WARN("GStreamer: Failed to create uridecodebin\n");
             close();
             return false;
         }
+    }
 
     if(manualpipeline) {
         GstIterator *it = gst_bin_iterate_sinks(GST_BIN(uridecodebin));
@@ -401,6 +401,7 @@ bool CvCapture_GStreamer::open( int type, const char* filename )
 
     if(gst_element_set_state(GST_ELEMENT(pipeline), GST_STATE_PLAYING) ==
        GST_STATE_CHANGE_FAILURE) {
+        gst_element_set_state(GST_ELEMENT(pipeline), GST_STATE_NULL);
         CV_WARN("GStreamer: unable to set pipeline to playing\n");
         gst_object_unref(pipeline);
         return false;