If you have ah ohmmeter (one function of a multimeter) test continuity between the pins on CN1 and the video cable header. If they're common, then it might be easier to adapt something.
Digi-Key sells a wide variety of flat flex cables. As you wrote, the difficulty is that this cable splits into two cables. Also the turns in the cable are a small problem, although I think you can deal with those by creative folding -- but not too much folding. Folding can easily break the conductors in the cable.
If CN1 connects, then it might be possible to get two flat flex cables from Digi-Key (or similar) which match the two smaller cables after the split. They can be bought with flat ends suitable for connectors as shown in your picture, or with tinned pinned ends that might be matable with CN1 and cables with one end flat and the other end pinned are also available.