Encode API with decoupled packet/frame dataflow. The API is the
same as the avcodec_ prefixed APIs (avcodec_send_frame() etc.), except
that:
- never called if the codec is closed or the wrong type,
- if AV_CODEC_CAP_DELAY is not set, drain frames are never sent,
- only one drain frame is ever passed down,
Encode API with decoupled packet/frame dataflow. The API is the same as the avcodec_ prefixed APIs (avcodec_send_frame() etc.), except that: - never called if the codec is closed or the wrong type, - if AV_CODEC_CAP_DELAY is not set, drain frames are never sent, - only one drain frame is ever passed down,