If I convert from YUV to RGB I loss quality?

[marcorocchini]

As in title, If I convert from YUV to RGB I get a loss of quality?

thanks

[poisondeathray]

Yes

[sanlyn]

Depends on how it's done. It can be done carefully with several proper methods (and if you can find an NLE app that does it properly, let us know). It's an even bigger problem going back to YUV for video encoding (and if you can find an NLE or decoder that does that one properly and carefully, let us know about that as well). I always use Avisynth methods and plugins, but only if I need to go to RGB for critical work.

However, the simple answer is poisondeathray's.

[jagabo]

There is not a one to one mapping of RGB to YUV values when working in 8 bit integer color. ~17 million RGB colors are mapped to ~11 million YUV colors when using the usual rec.601 or rec.709 colorspaces. So you get a loss of precision when converting one to the other. If you convert YUV to RGB, then convert back to YUV you will not have exactly the same YUV values you started with. Especially if some of the YUV values where outside the "legal" range.

YUV is also usually sub sampled (4:2:2 or 4:2:0) so the colors are usually interpolated when converting to RGB, then again going back to YUV. This results in blurring of the colors.

[Cornucopia]

Even without subsampling, all known mapping strategies for converting YUV<-->RGB color spaces don't use more than a few decimal places of precision beyond integer, so there is ALWAYS rounding, and thus LOSS.

Scott

[sanlyn]

The losses begin with YUV. Everything in graphics begins as RGB. Once you start denuding pixels, it's downhill from there.