YDbDr is the colour space used in the SECAM colour television broadcasting standard, which is used in France and some countries of the former Eastern Bloc. Y is the luminance, and Db and Dr are the red and blue colour differences. These are related to the RGB colour space as follows.

Y  = + 0.299R + 0.587G + 0.114B
Db = + 1.505(B - Y)
   = - 0.450R - 0.883G + 1.333B
Dr = - 1.902(R - Y)
   = - 1.333R + 1.116G + 0.217B

Db and Dr are related to the U and V components of the YUV colour space as follows.

Db = + 3.059U
Dr = - 2.169V

There is also a variety of the PAL broadcasting standard, PAL-N, that uses the YDbDr colour space.