/* notify subclass of preroll buffer or real buffer */
GstFlowReturn (*preroll) (GstBaseSink *sink, GstBuffer *buffer);
GstFlowReturn (*render) (GstBaseSink *sink, GstBuffer *buffer);
/* notify subclass of preroll buffer or real buffer */
GstFlowReturn (*preroll) (GstBaseSink *sink, GstBuffer *buffer);
GstFlowReturn (*render) (GstBaseSink *sink, GstBuffer *buffer);