While early color television experiments were kept in the component domain of RGB, most color television broadcasting and post production was compromised in the 1960s and 1970s to simplify infrastructure and transmission by combining the color and luminance (composite). However, once the color and luminance information was combined, it could never truly be uncombined as cleanly as originated. Component video was rarely processed through a video facility as RGB, as it is in computer displays. There was a historical legacy need to maintain black-and-white signals. Further, as the human eye is more sensitive to black-and-white picture information than color, engineers calculated that with the size of the largest home television screen, the color video lines did not need to be sampled for every converted digital pixel. Sony's 1982 news-gathering 1/2-inch video format Betacam, the first camcorder combination came up with a compromise, known as YUV. The "Y" was
luminance, or the detail of the video picture, in black-and-white. It contained the sync 'frame' needed to make a stable picture. If one connects only the "Y" cable, one can see a black-and-white image, but not if only connecting the other two color information channels. The "UV" was a math algorithm of
R-Y (red minus luminance) and
B-Y (blue minus luminance). The green information was derived by the difference (thus
YUV is referred to as color difference processing). For example, if there are five black-and-white panda teddy bears in a box (Y); plus eight red apples (R-Y) and two blueberries (B-Y); and the total number of items has to equal 20, one can easily calculate how many remaining green apples there are, as 20 minus 15 would leave a difference of five. When engineers sought to process and record in real time the huge amount of digital data needed to make the first digital video tape format, keeping the Y, R-Y, B-Y or YUV algorithm was key to simplifying and reducing the initial picture information sampled, saving valuable space. 4:2:2 is Y, R-Y and B-Y; not RGB; 4:2:2 is often erroneously quoted as 4 meaning red, and the remaining 2s standing for green and blue. If this were true, it would produce an uneven recording of green and blue data compared to red. In a given small sample of the video picture – for instance the first four pixels going across horizontally in the top-left corner of the screen, the first "4" means that the more important luminance/black-and-white picture detail was sampled in every pixel in that 4-sample. The next two 2s mean that R-Y and B-Y were sampled at every other pixel, skipping the one in-between. The eye should not be able to see the two in-between pixels not having the actual color information that the originating camera recorded – previous color pixel is simply replicated. Thus with 4:2:2, all color, red, green and blue, is sampled at half the rate of the black-and-white (luminance) picture detail. You could say that 50% of the color is actually recorded – because for the TV screen, it was good enough for the human eye. The popular 1995/96 1/4-inch DV/DVCAM/DVCPRO format had a component digital YUV sampling of 4:1:1, meaning only 1 out of 4 pixels or 25% of the color is actually recorded, which is why the color looks "muddy" and not as vibrant when compared to any 4:2:2 recording. This made green screen mattes lower quality on the format. The DV format further compressed the digital data at 5:1, to get 25 million bits per second onto a small tape moving at a slow speed. Subtle compression artifacts were sometimes visible. Modern high definition video recorders like Sony's HDCAM-SR format, SR stands for superior resolution, have the ability to switch between 4:2:2 and full RGB recording for giant-screen motion picture work, thus RGB is sampled at every pixel and branded 4:4:4. ==Models==