🚀 go-pugleaf

/ hplred:comp.multimedia / pej@hpfcso.FC.HP.COM (Phil Jensen) /  6:04 am  Jul 27, 1992 /
> In comp.multimedia, soam@freyja.cs.cornell.edu (Soam Acharya) writes:
> > Can anyone point me towards a reference that explains how to convert
> > 4:1:1 subsampled YUV data to RGB? 
> > 
> 
> Call your local Signetics Rep and ask for the Phillips Video Data Handbook.
> This contains specs on the parts that are on your board. Look at the SAA7192
> Digital Colour Space Converter. This is a YUV to RGB converter. Included are 
> equations for the YUV to RGB conversion.

Actually, the Signetics book gives the equations for YCbCr (normalized
YUV, so they're essentially the same).  I just happened to be typing
in these numbers so I can save you some time:

|R|   | 1.000  0.000  1.000 | |Y|
|G| = | 1.000 -0.186 -0.508 | |U|
|B|   | 1.000  1.000  0.000 | |V|

|Y|   | 0.299  0.587  0.114 | |R|
|U| = |-0.299 -0.587  0.866 | |G|
|V|   | 0.701 -0.587 -0.114 | |B|

And if you want to use YCbCr,

|Y |   |     Y     |
|Cb| = | 0.564 * U |
|Cr|   | 0.713 * V |

Benson's "Television Engineering Handbook" (ISBN 0-07-004779-0),
though poorly organized and containing plenty of typos, contains all
kinds of stuff like this.  It's a better general reference than the
Sig.  data book, but it's far from free (~$100, I think).

Andrew Fitzhugh
Computational Color Reproduction
HP Laboratories