Is there any wire with many small wires which i can use for multiple video signal
This 3M cable is available in 7 to 50 twisted pairs. Outer diameter for the 8 pairs is 5.84mm. Available from Digikey, not cheap.



The ends shown seem to be untwisted, which often happens during stripping of the isolation. If you want to be sure the cable has enough twists (about 1 full twist every 5cm is nice), ask a sample from 3M.

Make sure to check the cable's impedance.