SYSTEM ZUR SYNCHRONISIERUNG VON HAUPT- UND HILFSVIDEOSIGNALEN

A system for synchronizing first and second video signals which are to be combined is disclosed. The second signal is data compressed digital signal containing macro blocks of composite data preceded by a field sync flag synchronized with the field rate of the first signal. Each macro block contains a video block including a plurality of image line blocks. Each line block contains multiplexed video data such as luminance and chrominance information preceded by a marker flag. The flag preceding the first line block in a video block is a field flag which identifies the beginning of a scanning field associated with that video block. The flags preceding other line blocks in that video block identify the other line blocks respectively. Each flag contains a unique data preamble which identifies the associated line block. Illustratively, field flag data includes unique header, field number, and "performance index" data for controlling data quantization. Line block flag data includes unique header, line block number and performance index data.