YUV Color Space

YUV^[1] defines each pixel has:

• one Y Luminance, luma vector
• two chrominance vector , where..
  • U is blue projection .
  • V is red projection.

It can be convert to and from RGB model and other color spaces.

Luminance:

Chrominance (U, V) (Blue, Red projection):

❓Why YUV instead of RGB

Typical RGB has 8 bits per compoment (R, G, B) with a total 24 bits per pixel. However, YUV can be 4 bits per compoment (Y, U , V) with a total 12 bits per pixel.
This reduce the space when storing pixel in the memory and reduce the bandwidth when video transportation.

❓What is YUV 8bits and 10bits?

YUV 8 bits and 10 bits are represent as the depth of each compoment, e.g. Y, U and V.

Common YUV format

YUV4:4:4 format

Each pixel contains Y, U and V compoments and each compoments are 1 byte.

YUV4:2:2 format

Each 2 horizontal pixels contains 2 Y, 1 U and V compoments and both pixels share the same U and V. YUV4:2:2 has different packed format, check here.

YUV4:2:0 format

Each 2 horizontal and 2 vertical pixels (total 4 pixels) contains 4 Y, 1 U and 1 V compoments and four pixels share the same U and V.

YUV4:1:1 format

Each 4 horizontal pixels (total 4 pixels) contains 4 Y, 1 Y and 1 U compoments and four pixels share the the same U and V.

⚙️ YUV444 to / from RGB888 conversion

to YUV Fomula:

to RGB Folula:

Where:

• *$R(G,B)\in [0,255]$
• *$Y\in [0,255]$
• $U\in [-112,+112]$
• $V\in [-157,+157]$