| A Digital Video Disc or DVD is one of the most | | | | Producing DVDs requires certain authentication. Also, |
| popular forms of storage media nowadays. It is an | | | | certain processes and rules are needed to be |
| optical disc and mainly used to store videos. | | | | followed to handle their production. Present day |
| However, data in any form can be stored on a DVD. | | | | markets are full of illegal and fake DVDs. Especially in |
| The dimensions of a DVD are generally the same as | | | | Asia, Africa and Brazil. So, certain security measures |
| a common compact disc but the amount of data | | | | are applied to check this illegal business. Copy |
| that can be stored is six times greater. | | | | prevention techniques are used that prevents illegal |
| The different variations of DVD are based on the | | | | replicating of the original disk. |
| way data is being stored on it. A DVD-ROM has | | | | A DVD-Video is standard for storage of video |
| pre-written data that can only be read. A DVD+R | | | | content on the media. Typically the format in which |
| and DVD-R are the ones on which the data can be | | | | video is stored in the DVDs is MPEG-2, 16:9 aspect |
| written only once; and on a DVD+RW the data can | | | | ratio videos. The resolution used are 720*576 (PAL) |
| be written and erased more than once. The lasers | | | | or 720*480 (NTSC) at 25 or 29.97 FPS. The audio on |
| used to read DVDs are typically of 650 nm | | | | the disc is stored in DTS (Digital Theatre System) or |
| wavelength. | | | | AC-3 (Dolby Digital) formats. However, a number of |
| The terms DVD-Audio and DVD-Video discs are | | | | other resolutions and formats are also supported. |
| DVDs with suitably structured and formatted audio | | | | Other features like selectable language in subtitles, |
| and video content respectively. Other types of DVDs | | | | menus, multiple audio tracks and more than one |
| are called DVD-data discs. | | | | camera angle is also supported by DVD-Video. |
| The term `DVD` is used for an unofficial full form | | | | The DVD-Audio format is used to deliver high-quality |
| `digital video disc`. However, it was officially | | | | audio content. A number of channel configuration |
| announced that it stands for `digital versatile disc`. | | | | choices (like from mono to 5.1 or 7.1 surround sound) |
| A typical DVD has a 4.7 GB storage capacity. These | | | | at a number of sampling frequencies are offered by |
| discs are one sided and single layered i.e. the data is | | | | the DVD-Audio. The higher storage capacities enable |
| stored only on one side of the disc and only at one | | | | it to store a considerable higher amount of music or |
| level. The size is enough for a high quality 133-minute | | | | a much higher audio quality. |
| movie. The double sided and dual layered DVDs can | | | | Although the DVD-Audio has higher technical |
| store about 17 GB of data in any form. The capacity | | | | specifications, the debate on whether the audio |
| dwarfs a compact disc easily. | | | | enhancements that are being included are actually |
| The writing speeds on a DVD vary from 1350 KB/s | | | | distinguishable or not in a typical listening environment |
| (1 x) to 26 MB/s (18 x to 20 x). For a CD, the speed | | | | is still on. |
| 1 x means only 153.6 KB/s. | | | | There are a number of possible successors to the |
| Initially, the burning or the duplication of DVD was an | | | | DVD. The strongest being the Blu-Ray Disc. Others |
| expensive work and required skilled persons to do it. | | | | are Maxell`s HVD (Holographic Versatile Disc) and the |
| Today, the process of writing on a DVD has become | | | | 3D optical storage discs that are being developed |
| a piece of cake and any one with a little knowledge | | | | actively. |
| of computers can do it at a click of the mouse. | | | | |