I have a couple of spare cameras I would like to repurpose
I just need a video stream.
I read in a few places that Arduino was too small to manage digital to ntsc (analog) but the camera appears to have a board the manages it's own processing. I want ntsc to digital. The opposite.
Would an Arduino or an ESP8266 (or its updated version) be able to hand this video over to serial or better yet IP? Or should I at least be working with a raspberry pi?
Capturing NTSC or PAL video is orders of magnitude more difficult and resource-intensive than simply generating NTSC or PAL output. An AVR-based Arduino is more than capable of doing the latter, providing it has some fairly simple hardware support, and it is doing almost nothing else. It would be totally incapable of doing the former.
Actually, you will find that Arduino projects that drive NTSC actually produce a signal that is a stripped down, pale imitation of NTSC. It would almost certainly be missing interlaced sync and chroma information.