YUV 422 , YUV 420 ,YUV 444
I have for example 4*4 image. I want to extract the Y,U and V components separately. How to do it if the image is YUV 422 ,YUV 420 and YUV444. I am interested in knowing the structure of array how Y,U and V are stored in 422,420 and 444, so that it can be accessed.
Answer
This site gives you a pretty good overview over the different YUV formats. There's also a pixel-structure given.
For clarification: These numbers are for determination of color component subsampling. For instance YUV 444 = 4:4:4 subsampling, meaning that every of the three components (Y, U and V) has the same sample rate. Whereas 4:2:2 states that U and V are only sampled with half the rate of Y. Or, in other words, 2 Bytes for Y and for U and V 1 Byte respectively, if the depth is 1 Byte. This implies that Y can have a higher dynamic range.
It is worth noting that JPEG standard defines horizontal and vertical sampling factors for each color component. The human visual system has a 20:1 ratio of the luma sensors (rods) to chroma sensors (cones). For this reason, typically luminosity component is not subsampled, but the JPEG standard does allow such content to be encoded.