Previously in this book you have seen the word NTSC, which might have looked like another obscure and cryptographic acronym for something that was designed to make your life harder. This section aims to explain what NTSC and PAL are, why they exist, and what they imply when processing video from NTSC or PAL sources. (DVDs ship with NTSC or PAL video only.) What I have not mentioned before is a third standard named SECAM that is used in a few countries around the world.
NTSC stands for National Television System Committee; the committee introduced a TV standard sometime in the early 1950s that inherited its name. The standard was aimed towards color television and, naturally, it aimed to satisfy compatibility with black and white devices and signals. In simple terms, a color TV should be able to decode a monochrome picture signal and vice versa, a black and white TV should be able to decode a color transmission without any modifications. This requirement resulted in the YUV...