RCA video input

I have a chase camera attached to my race car with RCA video output. I usually drag a television out into the garage to set up the camera (centering and focusing), but at the race track this isn't possible...

I'm hoping there is a way to input the RCA feed onto my MacBook Pro. For example, I read about an RCA-USB adapter "DVD Grabber", but I'm not sure if or how this would work.

Suggestions?

Thanks in advance!