FIELD: masking systems for video data lost in the course of transmission. SUBSTANCE: compressed-to-decompressed data conversion system has device for receiving compressed data, device for detecting errors in compressed data coming from receiving device, and decompression facilities, replacing data shaping facilities, facilities for replacing compressed data blocks supplied from receiving device by replacing data supplied from replacing data shaping facilities in case error is detected by error detecting device; decompression facilities supplied with data from compressed data block replacing facilities are made for replacing decompressed data corresponding to mentioned replacing data decompressed earlier by image data. System for processing compressed video data transmitted in the form of blocks has decompression facilities, device for error detection in mentioned compressed video data blocks, device for shaping replacing data simulating compressed video data, device for replacing compressed video data blocks in which errors are detected by error detection device by mentioned replacing data, facilities for replacing decompressed video data corresponding to mentioned replacing data by decompressed data having same spatial position with time shift connected to decompression facilities and to error detecting device. EFFECT: provision for transmitting data of different level of significance at different power levels. 8 cl, 8 dwg
