Compressed digital video overlay controller and method

(-- 57) summary -- to the specific domain of the 1st television picture generated by the video signal by which the 1st was compressed in digital one, the 2nd picture materialized by the 2nd video signal is overlaid. A controller is equipped with I frame buffer which memorizes the pixel data of a macro block in which I frame format drawn from the 2nd signal was updated. A controller is equipped with the mat mask storage register which memorizes the data which demarcates the domain pinpointed by the macro block again. A mat substitution processor communicates with the mat mask storage register, has the 1st signal as an input, and offers the overlaid output further. A controller also prevents transfer to the output of which macro block of the data flow of the 1st signal in a specific domain. It functions as replacing such a macro block with a macro block corresponding from I frame buffer.