Overlay controller for multiple overlays

摘要

The method employs a memory (1) for video data of independent images (D1-D3). The images are read out sequentially into different video channels via a multiplexer (MUX). The physical channel (2) has a buffer memory (FIFO), decoder (DEC) and overlay controller (OVL) with synchronous control for insertion of video data at desired co-ordinates in random-access memory or a video monitor (3). A local microcontroller (CU) guarantees the necessary rapid and precisely timed reprogramming of the overlay controller and synchronous operation of other components of the system. The multiplexer is driven at a higher rate to restore the picture repetition rate which is reduced by alternate transmission of the video sequences (S1-S3) from the different channels.