My old Diamond video capture didnt work with the current MacOS or M1 Macs in general, so I tried this Elgato Video Capture device which was $80. I read mixed things about it working on M1 Macs, but found an article on Elgato's web site pointing to a new version of their video capture software that works with M1, so I took a chance on the USB hardware atually working.
Got it today, plugged it in, MacOS asked if it was OK to connect, sure! Started up the capture software and it works perfectly. Actually way better than the Diamond one ever did.
Heres a quick capture I did straight out of the box. Notice it is crystal clear, however it is slightly tinted toward purple. In the capture software, you can adjust RGB, Hue and Vibrance (?). I suspect a minor tweak will correct it. The software is written by Roxio I beleive, but branded as Elgato, dead simple to use which is a bonus. I believe this will also work with OBS if you want to stream. Note that the uploaded video was handraked from the original size but still very clear (at about 1/8 the original size of 7.2MB).
If you need/want a video capture solulution that includes S-Video and Composite with left/right audio on M1 Mac, this is the way. Not expensive and works like a champ.
Wade