quich question on colorspace

[TimurCivan]

ok i hear 4:4:4, 4:2:0, 4:1:1 thrown around a lot. i kinda understand how the sampling works. but visually speaking, is 4:2:0 better or worse than 4:1:1. Like i know 4:1:1 has trouble with very saturated reds, and oranges. But does 4:2:0 have similar problems???? or is it more well rounded?

 

[Barry_Green]

Well, interesting question, and an interesting answer. It's tempting to say that no, there's no difference in how color gets processed based on whether you're using 4:2:0 or 4:1:1... they're just patterns of pixel sampling, which has nothing to do with the saturation of the colors.

But, 4:2:0 is used in PAL, and 4:1:1 is used in NTSC, and PAL definitely has better color handling than NTSC. Not because of the 4:2:0 or 4:1:1, but because PAL was developed later than NTSC and just has better color.

4:2:0 and 4:1:1 are basically the same, just a different pattern. Both systems encode one chroma sample for every four luma samples, so it's a case of "six of one, half-dozen of the other." 4:2:0 is fine for progressive, but (as Graeme says) it's ghastly for interlaced. 4:1:1 works fine for either progressive or interlaced. Panasonic chose 4:1:1 for their PAL DVCPRO25 format, which broke compatibility with the other DV25 PAL formats.

Adam Wilt, Avid, Poynton, and Graeme Nattress have all published articles and discussions on the different color sampling techniques, if you want to do a little googling and a lot of heavy reading...

 

[TimurCivan]

grazie barry.