System of video recording/playback by alternation of half- frames for simultaneous recording of two different programs on video cassettes and playing them back separately

摘要

The subject of the invention is a system of video recording/playback by alternation of half-frames for the recording on video cassette of two different superimposed programs and for their separate playback, in which during the recording the two video signals V1, V2 of the two different programs are composed by a composer unit into a single resultant video signal V1+V2 consisting of one half-frame (odd or even lines) of the first signal and one half-frame (even or odd lines) of the second signal and, during playback, each frame of said resultant video signal V1+V2 is decomposed by a decomposer unit into the two component half-frames (even lines and odd lines), one corresponding to the first video signal V1 and the other corresponding to the second video signal V2, it being possible to use said signals separately after putting them through a duplicator unit which adds to each half- frame obtained by the decomposition an identical half- frame obtained by duplication, so as to reconstruct a whole frame. IMAGE