Re: Question about video signals
You would need a device known as SplitTechnologies. It is a processor that splits the image to be sent to multiple displays. the ict SplitMachine HR 22 can do a 2x2 (4 screens). The ict SplitMachine HR1500 can do 6x6 (36 displays) and the HR3000 goes up to 7x7 (which should be 49 displays, but it claims the ability to drive 52 displays).
There are others out there, as well as entire companies that are dedicated to video walls. If you want a DIY verison, you may be able to build a dedicated PC with software that can process the signal and has enough outputs to export to your video screens.
Personally, if you want a large video display, I would go with a projector. Video walls are good for businesses and showrooms.