What is Component Video?

Y, U,  V

Y,  I,  Q (NTSC version of YUV)

Y, B-Y, R-Y

Y, Cr, Cb

Y, Pr,  Pb

All of the above are different component video standards ! 

Component video comprises three separate signals. One of these conveys the luminance information, and the other two convey information of the colour content of  a picture. Like RGB is can produce an extremely high quality picture. The Y or luminance signal contains the main picture information and  a combined 0.3V sync the other 2 signals contain the colour difference information. If you remove the sync from the equation then there is a relatively simple mathematical relationship between component video and RGB. The different flavours of component video simply differ slightly in the relative amounts of each signal. As most digital sources use the Y Cr Cb format this is the one most commonly found on consumer equipment and the one supported by the Keene Electronics Compnent2RGB convertor.  The Y, Cr, Cb system is the CCIR 601 standard adopted for most digital video applications. The traditional YUV is more often found on analogue professional equipment. Rather perversely the Y Cr Cb system adopted for digital video encoding is sometimes referred to as CAV or Consumer Analogue Video.

There is some confusion over the exact meaning of YCrCb and YPrPb. This seems to have come about because one school of thought (English) refers to YCrCb as an analogue signal and YPrPb as its digital equivalent. Another school of thought (This time American) suggests that YCrCb is interlaced and YPrPb is progressive. (As we are a British company we favour the British version!).

When buying component video equipment it is very important to make sure you get the right flavour of component for the equipment you are using. If you for example want to connect to a plasma display then nearly all of these use Y Pr Pb and connecting with YUV will produce a heavily tinted picture.

YUV = Y B-Y R-Y

The ratios for UV to Cb Cr are: Cb=(B-Y)/1.771 and Cr=(R-Y)/1.402 for the above standard.

Traditional analogue YUV (Y B-Y R-Y)

RGB -> YUV

Y = 0.299*Red+0.587*Green+0.114*Blue

U= -0.299*Red - 0.587*Green + 0.886*Blue   

V= 0.701*Red – 0.587*Green – 0.114*Blue

YUV -> RGB

Red = Y+ V

Green = Y – 0.195U – 0.509V

Blue = Y+ U

CAV or Digital Y Cr Cb

RGB -> Y Cr Cb

Y = 0.299*Red+0.587*Green+0.114*Blue

Cb = -0.169*Red - 0.331*Green + 0.5*Blue

Cr = 0.5*Red – 0.418*Green – 0.082*Blue

Y Cr Cb -> RGB

R= Y+1.402Cr

G= Y – 0.346Cb – 0.714Cr

B= Y + 1.771Cb