[ NoWrapper ]
public virtual FlowReturn aggregate_frames (Buffer outbuffer)
Lets subclasses aggregate frames that are ready.
Subclasses should iterate the GstElement.sinkpads and use the already mapped Frame
from get_prepared_frame or directly use the
Buffer from
get_current_buffer if it needs to map the buffer in a
special way. The result of the aggregation should land in outbuffer.