frame must have a valid encoded data buffer, whose metadata fields
are then appropriately set according to frame data or no buffer at
all if the frame should be dropped.
It is subsequently pushed downstream or provided to pre_push.
In any case, the frame is considered finished and released.
After calling this function the output buffer of the frame is to be
considered read-only. This function will also change the metadata
of the buffer.
frame must have a valid encoded data buffer, whose metadata fields are then appropriately set according to frame data or no buffer at all if the frame should be dropped. It is subsequently pushed downstream or provided to pre_push. In any case, the frame is considered finished and released.
After calling this function the output buffer of the frame is to be considered read-only. This function will also change the metadata of the buffer.