I think I found a bug in function CvCapture_GStreamer::open. There is a call <pre> gst_caps_unref(caps) </pre> on line 408, but the variable <pre> caps </pre> is uninitialized. I think that the solution is to first assign the return value of the <pre> gst_caps_new_simple(...) </pre> to the caps variable and only than call into <pre> gst_app_sink_set_caps(...) </pre>. gst_app_sink_set_caps(...).