@woland said:
I would set the 'size px' to 6, 'repetitions' to 6, and 'spacing px' to 1?
Sure, that will work. You may want to crop/chop your video to narrow down on the region/s you want to select color from. I generally select the section of video I want to analyze, then scale it down (as low as 6px by 6px for your case) and then feed that into the Matrix Color Send actor. By scaling down you are basically averaging all the colors in a zone down to the one pixel.
So for example, if you selected a 60 px by 120px area as the control area from your video feed, you could scale that down to 6x6 and get a fair representation of the colors on those 36 zones/blocks. Depending on your goal, you may need to experiment a bit to find the right balance of color blending vs accuracy.