DVD video
| Storage medium DVD video
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 logo |
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| General | |
|---|---|
| Type | optically |
| capacity | up to 8.5 GB |
| lifespan | about 10 years |
| size | 12 cm x 1.2 mm |
| use | Video films |
| origin | |
| developer | DVD forum |
| idea | 1995 |
| Launch | 1997 |
| predecessor | Video cassette , video CD |
| successor | Blu-ray Disc , HD DVD (formerly) |
A DVD-Video is a film stored on a DVD in DVD-Video format, a technical specification for the storage of videos on a DVD data carrier. The data carrier itself is sometimes referred to as DVD-Video, and the DVD-Video format is sometimes referred to as “DVD-Video” for short. The DVD-Video format was created by the DVD Forum to guarantee future security and problem-free playability on all devices, but not least to keep the medium under the control of the film industry - according to the standard, DVD-Videos can only be played on authorized devices be played. The DVD-Video format is the best-known DVD variant, which is why the vernacular also imprecisely describes the corresponding film data carrier as DVD. Other well-known synonyms of DVD video are DVD feature film , DVD film, or DV film for short .
History and future
Development concepts
The DVD-Video format is the successor to various data carrier formats for video data , such as VHS cassettes, video CD or laser disc. The resounding success of the DVD-Video format since its market launch in 1997 is based on the fact that the disadvantages of its DVD predecessors have been avoided, but their advantages have been adopted, but especially on its versatility, both on personal computers with a DVD drive (using media players ) and to be playable on DVD players through a television .
- From the Video-CD format , the DVD-Video developers adopted the idea that a drive for a video data carrier could also play the audio CDs that were already widespread at the time . Such a solution is very attractive for consumers, because when they buy a drive they can use it flexibly for audio or video.
In most parts of the world, however, the video CD was at least a commercial flop. Although the video CD format, like the audio CD format, offered greater ease of use than the video cassettes known at the time (no rewinding and no tape wear), the video CD did not offer a higher quality than its predecessor like the audio CD. The picture quality of the video CD was somewhat poorer, especially compared to the popular VHS cassette; In addition, there was the much shorter playing time, which was insufficient for feature films. The cause was the insufficient storage capacity of a CD for the video compression algorithms known at the time . Despite these drawbacks, the video CD has almost completely supplanted VHS in Japan. Device manufacturers responded by researching CD-like data carriers with higher storage capacities. - From the very popular VHS cassette , DVD developers learned that the success of a video data carrier not only depends on its technical performance data , but also on its distribution .
With the video cassette, there were initially different video cassette standards, such as Betamax , Video 2000 , etc. Ultimately, the lower quality VHS cassette prevailed because it spread faster through clever marketing. The film industry companies suffered from the competition of video cassette standards in the entertainment industry because they had to offer their films in multiple video cassette standards simultaneously if they were to reach all consumers. The film industry wanted to avoid these increased production costs with the next video CD generation and intervened in the two parallel developments of the multimedia CD (MMCD, from Sony and Philips) and the super density CD (SD, from Toshiba and Time Warner). The film industry was in an influential position in this further development because without its films, the content for the videos was missing. The balance of interests between the manufacturers of entertainment electronics and the film industry was organized institutionally for the first time, through the DVD Forum , which determined the successor standard in consensus between the two industries. It was only this consensus that made the rapid market penetration of DVD-Video possible, because there was only one technical solution from the most important device manufacturers such as content providers. - From the laser disc , the DVD developers learned that for the buyer of a Video-CD-like data carrier, in addition to the film, extras such as audio commentary, background reports and trailers are crucial . These extras represent a significant additional benefit for the film lover compared to a possible VHS recording from television. They are included on most DVD videos.
These were the three main predecessors of DVD-Video, many of which the DVD-Video format inherited from. Originally, DVD-Videos should only be called DVD for short , for Digital Video Disc (English for "digital video disc "). The longer name DVD-Video came about because it was later decided in the DVD Forum to use all CD variants, such as B. to replace the audio CD , video CD and CD-ROM with a common data carrier with higher storage capacity. In addition to the DVD-Video u. a. the formats DVD-Audio and DVD-ROM . The three letters “DVD” were initially “repackaged” to Digital Versatile Disc (English for “digital versatile disc”). In 1999 the DVD Forum stated that DVD was a meaningless combination of letters.
Market development
The DVD Forum's first DVD-Video specification came out in late 1995. However, DVD-Videos did not go on sale until 1997 because the film industry insisted on an extended specification that supports its classic marketing strategies. For this purpose, two technical distribution controls were built into the DVD-Video, the regional code and copy protection ( see chapter Distribution control ).
- The first DVD players - which could also play audio CDs - came on the market at the end of 1997 and typically cost the equivalent of around € 700 to € 900. With the ever faster decline in the price of DVD players and the associated films with simultaneous technical improvements, the spread of the DVD video format grew. Since mid-2004, DVD players have been available from around € 40.
- Since 2001, more feature films have been sold on DVD in Germany than on VHS cassettes.
Todays use
DVD-Video is not only used to play videos for sale, but has also been used since the turn of the millennium to record television films or to watch amateur films. You can create your own DVD videos with the writable DVD versions DVD ± R , DVD ± RW and DVD-RAM . This was made possible because the writable DVD variants do not have to be pressed industrially , but can be created with so-called DVD burners and DVD video recorders . DVD videos are thus replacing video tapes, such as VHS , S-VHS and Hi8 tapes, etc. in their last bastion.
Successor technology
While there were many different successor technologies in the years 2000 to around 2008 ( Enhanced Versatile Disc - EVD, Finalized Versatile Disc - FVD, Versatile Multilayer Disc as well as HD DVD and Blu-ray Disc ), except for Blu-ray Disc the Development and / or marketing of all these alternatives stopped, so that according to the current status (2014) this has prevailed as the successor to the DVD.
DVD-Video from the user's perspective
From the user's point of view, the significantly better picture and sound quality is mentioned as a decisive argument in favor of DVDs compared to their predecessors. In addition, the playback mechanism is much less subject to wear because it works without mechanical contact. Due to the digital storage of the data, the image quality does not directly depend on the condition of the medium. In addition, there is no winding; Random access to a DVD is possible. This also enables non-sequential functions such as direct access to individual chapters.
In addition, some DVDs have additional functions such as additional audio tracks for additional synchronization versions or for comments on certain scenes. Switchable subtitles are also possible. Often bonus material is included, such as production documentation of the film, interviews and comments with those involved in production such as directors , actors or other extras such as cinema trailers , music videos or even computer games .
If activated, the copy protection and the region code of a DVD can prove to be disadvantageous for the user.
- On a PC that only runs open source software (e.g. from one of the many Linux distributions ), there is practically no authorized playback option for content scrambling system- protected DVDs ( OEM players are an exception ) . Playback is then only possible by breaking the protection, which in many countries (including Germany, Switzerland) represents great legal uncertainty or is even illegal, even if you have bought the DVD to be played yourself.
- It is also not possible, for example, to play a DVD from the USA on a player purchased in Germany without breaking the regional code protection. In the meantime, however, so-called region - free players are also available in Europe , which can not only play any DVD regardless of its origin, but also a wide variety of other formats and codes ( MP3 , DivX ).
- The DVD-Video specification offers the manufacturer the option of incorporating so-called User Operation Prohibitions (UOPs, “user operation prohibitions ”). This enables certain operating functions such as B. free selection of chapters or "fast forward" blocked for the user. Many DVD manufacturers make it excessive use, so as not skippable "anti- piracy " spots to incorporate advertising for other films and the like. However, some software players completely ignore this feature (e.g. VLC player ) or offer the option of deactivating it (e.g. Nero ShowTime ).
With some DVD players you also have to remember the current position in the film yourself; a tape already remains physically in this position. In addition, DVDs are relatively susceptible to mechanical damage (but significantly less than CDs) because they usually have no built-in protection against it. Appropriate solutions ( caddy , anti-scratch coating ) have not caught on on the market.
Spread control
The DVD-Video format is the first video data carrier to be specified jointly by device manufacturers and the film industry. The film industry pays particular attention to a technical distribution control, which should allow its traditional marketing of films without change even in the age of DVD videos.
Region code
Justification for the RPCs
The regional code, which is exactly called Regional Playback Control (RPC) , should prevent e.g. B. a DVD-Video from the USA can be played on a European device. From the film industry's point of view, this is necessary for a number of reasons:
- Even today's cinemas are primarily supplied with film rolls, the reproduction technology of which is so time-consuming that, according to the Motion Picture Association (MPA), not all cinemas in the world can be supplied at the same time. However, this claim was refuted with the simultaneous international premiere of the first The Lord of the Rings film and the second Star Wars trilogy. In addition, this argument cannot be used to justify why DVDs with classic films that were released in theaters years or decades ago are also given regional codes.
- On the other hand, it is said that without a regional lock, all consumers would have to wait for the DVD videos until the last theatrical release of the film around the world has been completed. In some cases, however, DVD sales now begin at the same time as the cinema release in the same region.
- The studios also sell distribution rights to various distributors. The distributors are happy if they can secure their exclusive market not only legally but also technically. Especially when a DVD-Video is to be sold at different prices depending on the market region. The regional code was intended to prevent "import", for example from the often cheaper USA to Europe.
- In order to better meet the different requirements for the protection of minors and age limits, the regional editions of individual DVD titles contain different versions.
- Finally, non-simultaneous marketing of a film in the world lowers the marketing risk in that each experience from one country can facilitate marketing in other countries.
From the point of view of the media user, regional codes are an obstacle, especially because many films and series in individual regions appear late, in abridged form or not at all. This can also result in less competition between the various DVD releases. Using special ripping programs , however, the regional codes / country codes can be selected or removed while they are being ripped to the hard drive . Many software DVD players such as MPlayer even simply ignore the regional code .
Technology of regional codes
A DVD-Video with clearly set regional codes can normally only be read by a DVD player that is set to one of these regional codes. The market also offers “Region Code Free” players that play DVD-Videos from all regions. Some devices can also be taught this with a firmware update or with codes that have to be entered via the remote control. However, this usually invalidates the guarantee. "Region code-free" players do not necessarily lead to success with every DVD-Video, since some DVD-Videos query the player's regional code through built-in scripting options and can behave differently accordingly.
The zone model of the RPCs
These codes are as follows:
| code | region |
|---|---|
| 1 | United States, Canada, and US Outer Territories |
| 2 | Western and Central Europe, Greenland, South Africa, Egypt and the Middle East, Japan |
| 3 | Southeast Asia, South Korea, Hong Kong, Indonesia, Philippines, Taiwan |
| 4th | Australia, New Zealand, Mexico, Central America, South America |
| 5 | Eastern Europe and other countries of the former USSR, India, Africa |
| 6th | People's Republic of China |
| 7th | Reserved for future use |
| 8th | International territory, for example in airplanes or on ships |
Colloquially, the terms regional code 0, RC 0, R0 have become commonplace for DVDs that have set several or even all regional codes. However, there is no official regional code 0 for DVDs - it is a manufacturer's name. For playback devices, “Region code 0” is used as a synonym for “ignores all regional codes”.
Encryption
Commercial DVDs are encrypted with the Content Scramble System (CSS), which is intended to prevent the making of unencrypted copies of the DVD (e.g. for distribution on other media) or the cancellation of the regional code. CSS led to problems for the developers of DVD players on an open source basis, because they cannot obtain the necessary keys for decryption from the DVD Copy Control Association - as these keys would also have to be published in the case of open source. Among other things, this led to the development of the open source program DeCSS .
technical structure
Here are some technical terms from the field of DVD authoring :
Directory structure and file names
The directory structure and file names of a DVD are also standardized. The following structure must be given in the UDF V1.02 file system format to ensure maximum compatibility with every DVD player:
AUDIO_TS
The directory AUDIO_TS (Audio Title Sets) is necessary for compatibility with DVD-Audio . Most of the time this directory exists, but is empty.
VIDEO_TS
.jpg)
The directory VIDEO_TS (Video Title Sets) contains the actual video data of a DVD-Video. The following files are specified there: a. to be found:
- VIDEO_TS.IFO This file contains information on the Video Manager Menu (VMGM) for structure and navigation as well as information on the playback of the VIDEO_TS.VOB files.
- VIDEO_TS.BUP Backup of the VIDEO_TS.IFO file (also called VMGI_BAK for "Video Manager Information Backup").
- VIDEO_TS.VOB contains the video objects for the title menu and multiplexed video, subtitle and audio files. This file is also known as VMGM_VOBS for "Video Manager Information Video Object Set".
- VTS_01_0.IFO (Video Title Set Information; VTSI); contains information about the Video Title Set and the Video Title Set Menu. The first number (01) indicates the title set number, the second number (0) is always 0.
- VTS_01_0.BUP VTSI_BAK; Backup of the VTS_01_0.IFO file.
- VTS_01_0.VOB VTSM_VOBS; contains the video objects of the VTS menu. This file is only available if this Title Set has a menu. The first number (01) indicates the title set number, the second number (0) is always 0 for Title Set Menu VOBs.
- VTS_01_1.VOB VTSTT_VOBS; contains the video objects of the title. The first number (01) indicates the title set number, the second number (1) the file number (the maximum file size on DVD-Video is 1 GB, so it may be necessary to split the data into several files).
JACKET_P
Certain DVD players use the optional and often non-existent directory JACKET_P (Jacket Picture) to read a graphic file from it for displaying a logo. This logo has to be stored several times for different resolutions and television standards:
- J00 ___ 5L.MP2 Image file in high resolution of 720 × 480 pixels for NTSC television
- J00 ___ 5M.MP2 Image file in medium resolution of 176 × 112 pixels for NTSC television
- J00 ___ 5S.MP2 Image file in small resolution of 96 × 64 pixels for NTSC television
- J00 ___ 6L.MP2 Image file in large resolution of 720 × 576 pixels for PAL television
- J00 ___ 6M.MP2 Image file in medium resolution of 176 × 144 pixels for PAL television
- J00 ___ 6S.MP2 Image file in small resolution of 96 × 80 pixels for PAL television
Video formats
The video data on a DVD is usually available as an MPEG-2 compressed data stream. The older MPEG-1 format of the Video CD is also supported, but has little practical significance. The standard provides a data rate for audio and video of up to 9.8 Mbit / s in total.
PAL DVDs (z. B. in Europe used) offer a resolution of 704 × 576/720 × 576 pixels with a frame rate of 25 Hz , while in America and in Japan spread NTSC DVDs a resolution of 704 × 480 / 720 × 480 points at a frequency of 29.97 Hz. On NTSC DVDs, however, videos can also be available in 23.976 Hz; a flag in the video stream tells the output device which fields it can show twice in order to achieve the 29.97 Hz required for NTSC output. Separate SECAM DVDs do not exist, as PAL and SECAM differ only in the type of color coding, but not in resolution and frame rate, and the color coding is not stored on the DVD, but only generated in the player when required.
On DVD-Video, video can be in fields (50 per second for PAL; 59.94 per second for NTSC) or full frames. So that output devices that can only work in full frames at the required frame rate can display the pictures better, it is possible to mark in the video stream which fields belong together and when put together they result in a full picture.
Pixels are not square on a DVD. The resolutions 704 × 576 and 704 × 480 both produce an image with an aspect ratio of exactly 4: 3. The resolutions 720 × 576 and 720 × 480 use the same pixels, which means that they produce an image that is slightly wider than 4: 3. 352 × 576 and 352 × 480 use pixels that are twice as wide, so that they also produce an exact 4: 3 image. 352 × 288 and 352 × 240 use pixels twice as wide and twice as high as 704 × 576 and 704 × 480, so that an image of the same size with a quarter of the resolution is created.
Videos can be saved anamorphically in the resolutions 720 × 576, 720 × 480, 704 × 576 and 704 × 480 . Anamorphic storage means that a 16: 9 video is compressed into a 4: 3 picture and rectified again during playback. This means that you do not need black bars at the top and bottom when saving (also called letterboxing ). When playing on 4: 3 televisions, the picture is compressed vertically by the DVD player and the black bars are created. However, if the picture is displayed on a 16: 9 television, the picture is transmitted to the television with the full 576 or 480 lines and rectified to full width there. This gives you a higher resolution on 16: 9 televisions than if the video were not stored anamorphically.
| resolution | system | Codec | possible aspect ratios |
|---|---|---|---|
| 720 × 576 | PAL | MPEG-2 | slightly wider than 4: 3, 16: 9 anamorphic |
| 720 × 480 | NTSC | MPEG-2 | slightly wider than 4: 3, 16: 9 anamorphic |
| 704 × 576 | PAL | MPEG-2 | 4: 3, 16: 9 anamorphic |
| 704 × 480 | NTSC | MPEG-2 | 4: 3, 16: 9 anamorphic |
| 352 × 576 | PAL | MPEG-2 | 4: 3 |
| 352 × 480 | NTSC | MPEG-2 | 4: 3 |
| 352 × 288 | PAL | MPEG-1 | 4: 3 |
| 352 × 240 | NTSC | MPEG-1 | 4: 3 |
Sound formats
The sound of a video DVD can be recorded in the formats PCM (up to 7.1 , uncompressed ), DTS (up to 5.1 and DTS-ES Discrete 6.1 , data-reduced), MPEG-1 Audio Layer 2 ( stereo , data-reduced), MPEG-2 Multichannel (up to 7.1, data-reduced) or Dolby Digital AC-3 (up to 5.1, data-reduced). NTSC players only need to support PCM and Dolby Digital, the other formats are optional.
In countries in which the PAL television standard is used, only PCM, MPEG-1 Audio Layer 2 and MPEG-2 Multichannel were originally intended as mandatory. However, following pressure from the general public and industry, Dolby Digital has also become a mandatory sound format for manufacturers of PAL-compatible DVD players.
A DVD-Video supports up to eight different audio tracks. This is z. B. used to accommodate different audio formats and / or languages on a DVD. There are also 32 subtitle tracks available.
Menu structure
DVD content is divided into titles (e.g. movies), which in turn can be divided into chapters (e.g. scenes). Titles and chapters can be viewed and selected using graphically edited menus; if there are no menus, the film content starts immediately when the DVD is played. In addition to the title and chapter menu , a DVD also has a so-called main menu , which is subordinate to the title menu and usually contains references to the audio and subtitle menus or to the chapter menu . When playing a DVD, the title menu is always opened first.
The designer has a variety of options to improve the interactivity of a DVD. There are several ways to build a DVD menu. The background of a menu can consist of a static image or a video stream. The same guidelines then apply to this as to the rest of the video material. The loop has to be created very cleverly so that a small jerk at the end of the video can be hidden as inconspicuously as possible. The means of choice range from morphing , to scenes of the same length, cut together in a sequence that is constantly repeated, to a simple slideshow of stills.
There are also various implementation options for the menu items. The most common method is to use subtitle tracks, with the help of which a menu item can be overlaid on a bitmap with a maximum of four colors and set in PAL resolution . This graphic can have three different states:
- not selected
- selected
- activated
Another possibility is to use “full color menus”, which has various advantages and disadvantages. Because in full-color menus the various menu items can be represented by full-color images, but a completely new menu background image must always be loaded, which can slow down navigation considerably. In addition, each menu item only has two states available:
- not selected
- selected
This is particularly annoying if a certain loading time elapses after activating a menu item, which becomes clear in the case of a subtitle track by the status "activated". This feedback is absent in a full color menu.
A menu may contain a maximum of 36 buttons. Please note that subtitle tracks are not scaled. This means that if a menu is to be in 16: 9 and 4: 3 on a DVD, the buttons with subtitle tracks must also be available in both formats. This means that only 18 buttons are possible per menu, as each button has to be embedded twice in the video.
programming
The playback behavior of a DVD can be determined by programming. There is also an instruction set and 16 memory locations, the so-called General Parameters - GPRMs, which can be used for your own programs. The GPRMs can be read and written directly. Each of these 16 memory locations can store a number in the range 0–65535 . Depending on the DVD authoring program used, the number of freely usable storage locations may be limited. The DVDMaestro program from Spruce Technologies, for example, allows you to use eight memory locations for your own programs; the remaining eight are used for internal purposes.
With the programming, for example, the behavior of the playback device can be determined when the menu button on the remote control is pressed while a film is being played. Here you can determine through appropriate programming that the button corresponding to the chapter currently being played is preset in the chapter menu.
Settings of the DVD player such as language and aspect ratio can also be read out. This information is in the so-called system parameters - SPRMs. These can usually only be read when programming. You can also write to a few using your own commands from the command set. An example is the SPRM 8, which contains the information as to which button is set.
Norms, standards and licensing
In contrast to the other DVD variants, such as DVD-ROM , DVD-RAM , etc., there are neither standards from ISO nor public standards from ECMA . The DVD Forum has not followed the usual path with DVD-Video because it gives it more options for ensuring DVD copy protection and the compatibility of DVD devices.
The exact DVD-Video specification is only available for a fee and under special conditions from the DVD Forum. Only manufacturers who meet the criteria of the DVD Forum are granted the right to affix the compatibility logo to their products ( licensing ), such as on DVD players or DVD-Video media.
See also
literature
- David A. Aydintan: The antitrust law admissibility of regional coding on DVD, Blu-ray Disc and HD-DVD: According to Art. 81 EG, § 1 GWB and international agreements . Kovač, Hamburg 2008, ISBN 978-3-8300-4128-3 .
Web links
- dvddemystiziert.de Frequently asked questions about DVDs from the group rec.video.dvd
- biff-filmfestival.de Background information on DVD production, such as formats, colors, problems
- Peter Riedlberger, Peter Mühlbauer : The return of the Volksempfänger by other means: How the DVD region code system curtails the freedom of information . Telepolis , May 4, 2001
Individual evidence
- ↑ a b Duden on gender and word meaning , accessed on April 5, 2013
- ↑ DVDs overtake VHS cassettes , report on Heise Online from November 8, 2001
- ↑ Peter Riedlberger, Peter Mühlbauer: The return of the people's receiver with other means , Telepolis, web document, May 4, 2001