gst.BaseSink.BaseSink is the base class for sink elements in GStreamer, such as xvimagesink or filesink. It is a layer on top of gstreamer.Element that provides a simplified interface to plugin writers. gst.BaseSink.BaseSink handles many details for you, for example: preroll, clock synchronization, state changes, activation in push or pull mode, and queries.
Undocumented in source.