ON SCREEN DISPLAY ARRANGEMENT FOR A DIGITAL VIDEO SIGNAL PROCESSING SYSTEM

A digital video signal processing system receives encoded packets of data representing video image information in compressed form. A video decoder and an associated video RAM are used to decode and decompress the video packets to form groups of video image representative digital words. The video image groups are organized in a compressed component format (e.g., Y, U, V in the ratio 4:2:2) related to the video image compression format in which pairs of color related components correspond to more than one pixel. The video decoder also includes an on-screen display (OSD) unit which converts a graphics bit map stored in a section of the video RAM to groups of graphic image representative digital words. The graphic image groups are organized in an uncompressed component format (Y, U, V in the ratio 4:4:4). Color related components of the uncompressed graphic image groups are deleted by a converter so as to form new graphic image groups having the same format as the video image groups which may be readily multiplexed with the video image groups to insert a graphics image within a video image.