.dirstamp adder alsa appsink appsrc audioconvert audiorate audioresample audiotestsrc decodebin encodebin libvisual multifdsink multisocketsink opus videorate videotestsrc volume vorbisdec typefindfunctions textoverlay videoconvert videoscale videoscale-[1-6] vorbistag playbin playbin-compressed playbin-complex playsink streamsynchronizer subparse rawaudioparse rawvideoparse