gst-launch-1.0 filesrc location=sintel-1024-surround.mp4 ! qtdemux name=demux demux.video_0 ! queue ! avdec_h264 ! videoconvert ! videoscale ! video/x-raw,width=512,height=218 ! x264enc ! h264parse ! mp4mux name=m ! filesink location=sintel-512-surround.mp4 demux.audio_0 ! queue  max-size-time=0 max-size-bytes=0 max-size-buffers=0 ! m.