picture_t * ( * pf_video_filter ) ( filter_t *, picture_t * );
block_t * ( * pf_audio_filter ) ( filter_t *, block_t * );
void ( * pf_video_blend ) ( filter_t *, picture_t *,
picture_t * ( * pf_video_filter ) ( filter_t *, picture_t * );
block_t * ( * pf_audio_filter ) ( filter_t *, block_t * );
void ( * pf_video_blend ) ( filter_t *, picture_t *,