Continued:

The next step is to understand how motion works or should we say, how we can deceive the brain into thinking that it is watching a live scene while in reality, it is just seeing a bunch of still shots being flipped through at a high speed.

Every video is a collection of frames. The concept is similar to animation (pre-flash days mostly) where if you drew slightly different images on successive pages of a pad and flipped through them rapidly enough, it would appear that the image was animated.

This is exactly how a normal TV works. It has a Cathode Ray Tube (Hence CRT) that draws an image on the screen pixel by pixel. If it works with interlace scanning then it draws each complete frame every 1/30th of a second and gives you a frame rate of 30fps (to continue with our notebook example, frame rate is the number of still images you will flip through in one second. In this case it is 30) progressive scanning, however, you get 60fps and unlike interlace scanning the entire scene is drawn at once and not alternately.

This is just the video part. The audio is completely separate, however. If you have ever linked a VCR or a DVD player to your TV, you might remember that there are two wires, the yellow one for the video and the Red/White for the audio.

Now this signal is fine by itself, but it’s way out of its league when compared to digital solutions. Of course, you may argue that it looks fine to you and you don’t find anything wrong with the image nor do you see the point of throwing out your trusty TV and getting in a hugely expensive DTV. Unfortunately, you would be wrong.

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