RGB and YUV colourspace

RGB and YUV colourspace

RGB - is the color space, which uses a number for each color. One for red, one for green, and one for blue. This number can be used to describe a precise color in the spectrum. An example of this would be, 8 bits defines 256 color scale, 16 bits defines 65,536 colors, and 24 bit defines 16.7 million colors. If you add the bits together you get the color depth of that image.


RGB can be thought of as three grayscale images (usually referred to as channels) representing the light values of Red, Green and Blue. Combining these three channels of light produces a wide range of visible colors.

YUV - is a color space derived from the PAL television color standard. Y is the luminance channel, U is the blue channel, and V is the red channel. 


RGB graphics are sampled at 4:4:4, but it is not practical to broadcast the much information, particularly when much of it is beyond our ability to perceive. YUV (Y’C B C R) reduces the amount of information required to reproduce an acceptable video image.

http://www.zerocut.com/tech/vid_img.htm

4:4:4 - a group of 8 pixels (4 by 2) the first number is representing the luma value or the brightness the next two numbers are representing the chroma so for a 4:4:4 image each pixel has both a luma value and a chroma value. 

4:2:2 -  all pixels will get a luma value because the human eye is very sensitive to this, but the chroma value will be shared across two pixels. 

4:2:0 the chroma value is shared across 4 pixels in a square...

4:1:1 the chroma value is shared across four pixels horizontally