YDbDr, sometimes written YD_BD_R, is the

colour space A color space is a specific organization of colors. In combination with color profiling supported by various physical devices, it supports reproducible representations of colorwhether such representation entails an analog or a digital represent ...

used in the

SECAM SECAM, also written SÉCAM (, ''Séquentiel de couleur à mémoire'', French for ''color sequential with memory''), is an analog color television system that was used in France, some parts of Europe and Africa, and Russia. It was one of th ...

analog terrestrial colour

television Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...

broadcasting standard (adopted in

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

and some countries of the former Eastern Bloc) and

PAL-N Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...

(adopted in Argentina, Paraguay and Uruguay). It is very close to

YUV YUV is a color model typically used as part of a color image pipeline. It encodes a color image or video taking human perception into account, allowing reduced bandwidth for chrominance components, compared to a "direct" RGB-representation. H ...

(used on the

PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...

system) and its related colour spaces such as YIQ (used on the

NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...

system),

YPbPr YPbPr or Y'PbPr, also written as , is a color space used in video electronics, in particular in reference to component video cables. YPBPR is gamma corrected YCBCR color space (it is not analog YUV that was used for analog TV, though component ...

and

YCbCr YCbCr, Y′CbCr, or Y Pb/Cb Pr/Cr, also written as YCBCR or Y′CBCR, is a family of color spaces used as a part of the color image pipeline in video and digital photography systems. Y′ is the luma component and CB and CR are the blue-diff ...

. YDbDr is composed of three components -

Y

D_B

and

D_R

Y

is the luminance,

D_B

and

D_R

are the

chrominance Chrominance (''chroma'' or ''C'' for short) is the signal used in video systems to convey the color information of the picture (see YUV color model), separately from the accompanying luma signal (or Y' for short). Chrominance is usually represente ...

components, representing the

red Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondar ...

and blue colour differences.

Formulas

The three component signals are created from an original RGB (red, green and blue) source. The weighted values of

R

G

and

B

are added together to produce a single

Y

signal, representing the overall brightness, or luminance, of that spot. The

D_B

signal is then created by subtracting the

Y

from the blue signal of the original RGB, and then scaling; and

D_R

by subtracting the

Y

from the red, and then scaling by a different factor. These formulae approximate the conversion between the

RGB The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three addi ...

colour space and YDbDr. :

\begin
R, G, B, Y &\in \left 0, 1 \right \
D_B, D_R &\in \left -1.333, 1.333 \right end

From RGB to YDbDr: :

\begin
Y   &= +0.299 R +0.587 G +0.114 B\\
D_B &= -0.450 R -0.883 G +1.333 B\\
D_R &= -1.333 R +1.116 G +0.217B\\
\begin Y \\ D_B \\ D_R \end &=
\begin 0.299 & 0.587 & 0.114 \\ 
-0.450 & -0.883 & 1.333 \\ 
-1.333 & 1.116 & 0.217 \end
\begin R \\ G \\ B \end\end

From YDbDr to RGB: :

\begin
R &= Y +0.000092303716148 D_B -0.525912630661865 D_R\\
G &= Y -0.129132898890509 D_B +0.267899328207599 D_R\\
B &= Y +0.664679059978955 D_B -0.000079202543533 D_R\\
\begin R \\ G \\ B \end &=
\begin 1 & 0.000092303716148 & -0.525912630661865 \\
1 & -0.129132898890509 & 0.267899328207599 \\
1 & 0.664679059978955 & -0.000079202543533 \end
\begin Y \\ D_B \\ D_R \end\end

You may note that the

Y

component of YDbDr is the same as the

Y

component of YUV.

D_B

and

D_R

are related to the

U

and

V

components of the

colour space as follows: :

\begin
D_B &= + 3.059 U\\
D_R &= - 2.169 V\end

There is also a variety of the

broadcasting standard,

, that uses the YDbDr colour space.

References

*Shi, Yun Q. and Sun, Huifang ''Image and Video Compression for Multimedia Engineering'', CRC Press, 2000

Formulas

References

See also