This is a format for presenting fonts in PDF files that was initially conceived to store symbols in the Japanese and Chinese languages because it had a 16-bit structure and allowed for more precise adjustment. CID expands the the potential for PostScript by supporting languages that do not have a left-to-right orientation, and by supporting even a vertical mode of orientation.
This format is used to store images that have been divided into Y, U, and V color components. In this case, Y corresponds to brightness, and the variables U and V correspond to color information. This format is able to store more accurate color information than the RGB color space. The YUV Color System also allows you to store video files and save a particular sequence of images.