DVD

What's all the hype about DVD? Do you get dismayed everything a new technology turns up rendering your current software/hardware obsolette? But this time DVD really changes life for the better. I myself had to go through videotapes and then later change to laser disc. You build up your new collection of laserdisc and all your effort are in vain and you have to abandon them again. You wonder, should you just stick with old and existing technology or do you go with the flow, join the crowd and embrace new technology?

The good news is DVD is indeed much better than the old videotape or laserdisc. DVDs are astonishing technology. Two thin discs can be bonded together so that both sides each hold 4.7 GB of information. Not only that , each side can have two layers of data, bringing the total storage data capacity to 18 GB. Wow! That's amazing. That's why besides storing movies in different formats, there is still space for different languages, subtitles and director's commentary. The best thing about DVD is that it allows you to skip to a specific scene you want immediately. There are index marks as well as chapter numbers to allow you to do so. DVDs also supports Dolby Digital.

Each single side with a single layer can hold 4.7 gigabyte of information which is seven times more than a CD. Both CDs and DVDs are the small size physically. How is DVD able to store a higher density of data? This is achieved by making the pits to encode the ones and zeros smaller and more numerous. Each side in fact can hold two layers of data.

Even though DVD can hold so much digital information, the original amount of video and audio data is still takes a much greater amount of space than the DVD can take. All the data can go into one DVD due to audio and video compression using dolby digital compression and MPEG2 digital video compression.

How does MPEG2 work? Suppose a scene shows a person walking against a stationary brown desert and a blue sky . Now the only thing that changes from frame to frame are the movement of his body and his facial expression. So only this data information is stored. The background is reused over and over again in each new frame, thereby saving space and storage. Actually, the technology is much more complex than this. This is just a simple explanation of the technology.