Digital Video - How Does It Work?

Digital video. In today's age we take this amazing piece of technology so much for granted. The truth is, that we are able to create digital video at all is simply amazing. To understand digital video you first need a basic understanding of analogue video or what is more commonly referred to as videotape or even before that, video film. Technically, motion pictures are simply the speeding up and displaying of still photos. Early motion pictures were recorded on film similar to photographic film. If you were to examine motion picture film it would look very similar to the negatives you'd see after taking your photos to the local photo-mart to be developed. To oversimplify things, motion pictures is simply taking those negatives, stringing them together and running them through a high speed projector to produce the illusion of movement. Of course the process today for film is much more complex than that but you get the basic idea. So then what is the difference between video film or tape and digital video? This is where we have to move into the area of computers. For the purpose of not confusing anyone this will be described as simply as possible. In order to create digital video you first have to start with an analogue or film image. Let's take for example a home camcorder which still uses video tape similar to the tape used in VCR tapes. After filming the moving image the camcorder would then be hooked up to a computer interface which is an analogue to digital converter. The film is then run through the converter where each image in the motion sequence is converted to a sequence of bits. The higher the bit concentration, whether it be 8 bit, 16 bit, 32 bit or higher, the more of the film quality that's preserved. The reason for this is because for each image to be salvaged the converter translates the image density, color, shape and other attributes into digital format. The more information there is to store the more bits are required to store it accurately. For example. it would not take as many bits to store the image of say a black tie as it would a photo of the Mona Lisa because the Mona Lisa has more detail to it. So some images you can get away with storing less information whereas other images you would not even be able to recognize what they were, even if you were storing the same amount of information. Again, this is simplifying things greatly. Okay, so what's the benefit of digital video if any? Actually the benefit is pretty great. With analogue film over time the film gets old and goes bad. So many old movies have had to be restored because of the terrible shape of the original prints. Some were so bad they couldn't be restored. With digital, there is nothing to get old. Bits don't age. So the digital video that you see today will look exactly the same 1000 years from today. With this technology you never have to worry about losing video of historic significance. A movie made today will not have to be restored 100 years from now. Artistic people will claim that the quality of digital video is cold, that you don't have the warmth of the look of film images. There may be something to that and the argument will probably go on for sometime about which is better. But one thing is for sure. Digital video is here to stay, which means that our films of our 25th anniversary celebration are also here to stay.