Scan Music Jitter Recipe

I like this patch and how it sonifies the video. I see that it turns the video into a 1 dimensional matrixin order to have it turned into sound by jit.release~. My question is how would one make 3 one dimensional matrices so that you could get all the info that's in the video into sound. Is this already done when it is rendered into the 1 dimensional matrix? I've tried to wrap my head around this but cant quite figure it out. is this done when you select the "scan line"?