DVD vs. CD vs. VHS

DVD vs. CD

DVD disks came into our lives not so long ago, but they have already become one of the most popular trends, surpassing even CD disks. There are several reasons why DVD format became more popular than the CD one. The main is that it has higher-density storage of information. DVDs also have a multi-layer storage.

Because pits and tracks on a DVD disk are smaller than those on a CD, the single-layer DVD disk can store seven times more information than a CD. There is a tighter spacing on a DVD's surface; the track pitch is 2.16 times smaller and the length is 2.08 times smaller as well. If multiplying these numbers, the result will be approximately 4.5. This means that there are by 4.5 times more pits on a DVD than there are on a CD.

There are a lot of additional encoded data stored on a CD to allow correcting errors. This extra data represents, in fact, a repetition of the information on the disk. The scheme of error correction is today obsolete and ineffective. The DVD format uses less space for error correction and much more space for storing real data. This is why DVDs represent a new and more effective generation of disks.

The DVD disk can have maximum four layers to increase the volume of information that can be stored on a DVD. There are two layers on each side of the disk. The laser, that stores and reads the information on a DVD, works with the second layer through the first one. This allows storing up to 17.1 GB of information on a single DVD disk.

DVD vs. VHS

Obviously, the DVD format is much more advantageous than the VHS one. Firstly, the quality of the picture stored on a DVD is much better. This format has also Dolby Digital sound, which comes close to the one in a cinema.

Most movies stored on DVDs have an on-screen index. With its help the user can view some important movie parts as well as pictures stored by their creator. There is no need for rewinding in order to see the favorite part of the movie. Using a remote control the user can instantly select the most favorite part.

There are two formats a DVD player can play: letterbox and TV size format. The former concerns a widescreen and the latter, being a standard format, fits any TV. DVD disks allow storing subtitles to the movies as well as several soundtracks.

DVDs will surely remain within the pages of high-tech history. The new era of video and audio formats is still to come, but today, however, DVD holds the position of the leader.

Print version