<A HREF="COL_.htm"><img align=center src="contents.gif" ALT="Contents"></A>

## ITU.BT-709 HDTV studio production in Y'CbCr

This is a recent standard, defined only as an interim standard for HDTV studio production. It was defined by the CCIR (now the ITU) in 1988, but is not yet recommended for use in broadcasting. The primaries are the R and B from the EBU, and a G which is midway between SMPTE-C and EBU. The CRT gamma law is assumed to be 2.2. White is D65. The chromaticities are:

```    R:      xr=0.64       yr=0.33
G:      xg=0.30       yg=0.60
B:      xb=0.15       yb=0.06
White:  xn=0.312713   yn=0.329016
```
The conversion equations for linear signals are:

```    X = 0.412*R + 0.358*G + 0.180*B
Y = 0.213*R + 0.715*G + 0.072*B
Z = 0.019*R + 0.119*G + 0.950*B
```
```
R = 3.241*X - 1.537*Y - 0.499*Z
G =-0.969*X + 1.876*Y + 0.042*Z
B = 0.056*X - 0.204*Y + 1.057*Z
```

The coding equations for non-linear signals are:

```    Y'= 0.2215*R' + 0.7154*G' + 0.0721*B'
Cb=-0.1145*R' - 0.3855*G' + 0.5000*B'
Cr= 0.5016*R' - 0.4556*G' - 0.0459*B'
```
```
R'= Y' + 0.0000*Cb + 1.5701*Cr
G'= Y' - 0.1870*Cb - 0.4664*Cr
B'= Y' - 1.8556*Cb + 0.0000*Cr
```

The conversion equations between linear 709 RGB signals and EBU RGB signals are:

```    Re= 0.9578*R7 + 0.0422*G7 + 0.0000*B7
Ge= 0.0000*R7 + 1.0000*G7 + 0.0000*B7
Be= 0.0000*R7 + 0.0118*G7 + 0.9882*B7
```
```
R7= 1.0440*Re - 0.0440*Ge + 0.0000*Be
G7= 0.0000*Re + 1.0000*G7 + 0.0000*Be
B7= 0.0000*Re - 0.0119*Ge + 1.0119*Be
```