You know, back in the 40s and 50s, the original standard television had a 4 to 3 width to height ratio. That shape was chosen to be a slight rectangle, but still mostly square, thus having the maximal screen area for the given dimensions. And that's still the ratio on many TVs and computer monitors in today's homes. The problem is, hardly anybody today treats video content in a 4 to 3 ratio. See, this whole problem started when people wanted to watch movies from the theater in the comfort of their own homes. Movie screens are considerably larger than our home television. More important, the screen is completely different rectangle, and can't mathematically fit on our TV screens without manipulation. A typical TV is one and a third times wider than it is tall . Some movie screens could be up to three times as wide as it is tall. So what're we gonna do to make it fit? Well, we have all kinds of options. Well, we could squeeze and stretch and mangle everything on to the screen, to make it all fill up, and everyone would look ridiculously thin and compressed. The good news is the sound would be just fine. Although I don't think people would be too happy about that option, particularly the actors in the movie. We could just cut a chunk of the original movie like a cookie cutter and just see that frame of the movie. The problem with that would be that people and objects would be speaking from off the screen, or even worse, they might be cut in half. Some movie editors use what's called the 'pan and scan' technique to allow the full height of the TV screen to be used.