+ bool is_blank( int clip );
+ bool is_blank_at( int position );
+ void consolidate_blanks( int keep_length = 0 );
+ Producer *replace_with_blank( int clip );
+ void insert_blank( int clip, int length );
+ void pad_blanks( int position, int length, int find = 0 );
+ int insert_at( int position, Producer *producer, int mode = 0 );
+ int insert_at( int position, Producer &producer, int mode = 0 );
+ int clip_start( int clip );
+ int clip_length( int clip );
+ int blanks_from( int clip, int bounded = 0 );
+ int remove_region( int position, int length );
+ int move_region( int position, int length, int new_position );