buf may be NULL in which case the indicated number of frames
are discarded and considered to have produced no output
(e.g. lead-in or setup frames).
Otherwise, source pad caps must be set when it is called with valid
data in buf.
Note that a frame received in #GstAudioDecoderClass.handle_frame() may be
invalidated by a call to this function.
Collects decoded data and pushes it downstream.
buf may be NULL in which case the indicated number of frames are discarded and considered to have produced no output (e.g. lead-in or setup frames). Otherwise, source pad caps must be set when it is called with valid data in buf.
Note that a frame received in #GstAudioDecoderClass.handle_frame() may be invalidated by a call to this function.