Compresión de señal YUV

4:4:4 means that each sample of luminance has corresponding samples of both U & V. This is effectively the same as full-bandwidth RGB - you can convert it to 4:4:4 YUV and back to RGB and the results will be identical.

4:2:2 means that you've halved the resolution of the colour difference signals along the line. The luminance resolution remains the same, but U and V are halved (only one UV sample pair for every two Y samples). Used in broadcast tape formats like Digital Betacam.

4:1:1 as above but colour resolution quartered. Used in broadcast tape formats like DVCPro and NTSC DV/DVCAM.

4:2:0 is slightly more confusing terminology, but it just means that the colour resolution is halved in both the horizontal and vertical directions. This is the technique used in digital TV broadcasting, DVD and PAL DV/DVCAM.