4:1:1 (one sample of each Cb & Cr for every 4 Y samples)
4:2:0 (same as 4:2:2 except color is sampled every other line)
4:2:2 (two samples of Cb & Cr for every 4 Y samples)
4:4:4 means equal samples of R,G,B (colors aren't combined into two vetors)
With 4:4:4 notice the slight increase in color resolution and the large increase in Y (black & white or luminance resolution)