What is pixel depth?

 Pixel depthIt refers to the number of BITs used by each pixel. The pixel depth determines the number of colors that each pixel may have, or determines the possible gray level of each pixel of a grayscale image. For example, each pixel of a color image is represented by three components: R, G, and B. If each component is 8 bits, one pixel is represented by 24 bits, that is to say, the depth of a pixel is 24 bits, and each pixel can be 224, that is, one of the 16777216 colors. In this sense, the pixel bit depth is often said to be the image depth. The more digits a pixel has, the more colors it can express, and the deeper it is. Although the pixel depth or image depth can be very deep, it is meaningless to pursue a particularly deep pixel depth due to the limitations of the device and the Resolution Limitation of the human eye. The deeper the pixel depth, the larger the data volume, the larger the transmission bandwidth and storage space required. On the contrary, if the pixel depth is too small, it will affect the image quality. The image looks rough and unnatural.

Tip: If the pixel depth is 8 (BIT), take the format 4: 2: 0 for the four pixels in the dotted box as an example, the samples have a total of 6 sampling points (4 brightness components plus 2 color components). A total of 6x8 = 48 bits are required, with an average pixel of 48/4 = 12 bits, this is why in some cases the 4: 2: 0 sampling format is also known as "12-bit sampling per pixel.