Are you planning on duplicating all the lines/resolution? Likely not. So have you decided on the resolution? How will you downscale from NTSC/PAL resolution to the resolution of your array?
In order to keep things simple, I plan to have the original video send in very low quality resolution. Hopefully low enough to match up with the resolution required. Don't know if that's possible though. Yes, I would be the one providing the low quality video.
Given the output of a high resolution grid, I can figure out how to make a low resolution grid out of it.
I looked at the LM1881 chip you posted. Looks like it has all the bells and whistles needed for inputting video signals. I don't know how to use this circuit though. The pages gives a lot of info about output of the chip...:
• Composite sync and vertical outputs
• Odd/even field output
• Burst gate/back porch output
• Edge triggered vertical output
• Default triggered vertical output for non-standard video signal (video games-home computers)
You know how to convert any of this into a simple analog grid?