The problem with Genlock is that it requires the original information's synch signal and there is no (to the best of my knowledge as I date from the tube and early non digital systems information contained withing a video line to regenerate the synch information when it is lost and the data it was encoded with unless you can store a lot of lines of video or count them to try and detirmine the frame synch that way, either way it does exceed the limitations of this forum because of the nature of the task and it's inherent complexity... IMO
Doc