VOB (for video object) is the

container format A container format (informally, sometimes called a wrapper) or metafile is a file format that allows multiple data streams to be embedded into a single file, usually along with metadata for identifying and further detailing those streams. Notab ...

DVD-Video DVD-Video is a consumer video format used to store digital video on DVD discs. DVD-Video was the dominant consumer home video format in Asia, North America, Europe, and Australia in the 2000s until it was supplanted by the high-definition Blu-r ...

media. VOB can contain

digital video Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises ...

digital audio Digital audio is a representation of sound recorded in, or converted into, digital form. In digital audio, the sound wave of the audio signal is typically encoded as numerical samples in a continuous sequence. For example, in CD audio, sa ...

subtitles Subtitles and captions are lines of dialogue or other text displayed at the bottom of the screen in films, television programs, video games or other visual media. They can be transcriptions of the screenplay, translations of it, or informati ...

, DVD menus and navigation contents multiplexed together into a stream form. Files in VOB format may be encrypted.

File format

Files in VOB format have a .vob filename extension and are typically stored in the

VIDEO_TS DVD-Video is a consumer video format used to store digital video on DVD discs. DVD-Video was the dominant consumer home video format in Asia, North America, Europe, and Australia in the 2000s until it was supplanted by the high-definition Blu ...

directory at the root of a DVD. The VOB format is based on the

MPEG program stream Program stream (PS or MPEG-PS) is a container format for multiplexing digital audio, video and more. The PS format is specified in MPEG-1 Part 1 (ISO/IEC 11172-1) and MPEG-2 Part 1, Systems (ISO/IEC standard 13818-1/ITU-T H.222.0). The MPEG-2 Pr ...

format, but with additional limitations and specifications in the private streams. The MPEG program stream has provisions for non-standard data (as used in VOB files) in the form of so-called private streams. VOB files are a very strict subset of the MPEG program stream standard. While all VOB files are MPEG program streams, not all MPEG program streams comply with the definition for a VOB file. Analogous to the MPEG program stream, a VOB file can contain H.262/MPEG-2 Part 2 or MPEG-1 Part 2 video, MPEG-1 Audio Layer II or MPEG-2 Audio Layer II audio, but usage of these compression formats in a VOB file has some restrictions in comparison to the MPEG program stream. In addition, a VOB file can contain linear PCM, AC-3 or DTS audio and subpictures (subtitles).Videohelp.co
What is DVD? Technical Info for DVD-Video
Retrieved on 2009-07-28 VOB files cannot contain

AAC AAC may refer to: Aviation * Advanced Aircraft, a company from Carlsbad, California * Alaskan Air Command, a radar network * American Aeronautical Corporation, a company from Port Washington, New York * American Aviation, a company from Cleveland, ...

audio (MPEG-2 Part 7),

MPEG-4 MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related tec ...

compression formats and others, which are allowed in the MPEG program stream standard. On the DVD, all of the content for one title set is contiguous, but if necessary is broken up into 1 GB VOB files in order to be compatible with all operating systems, as some cannot read files larger than that size.

Companion files

VOB files may be accompanied with IFO and BUP files. These files respectively have .ifo and .bup filename extensions. IFO (information) files contain all the information a DVD player needs to know about a DVD so that the user can navigate and play all DVD content properly, such as where a chapter starts, where a certain audio or subtitle stream is located, information about menu functions and navigation. BUP (backup) files are exact redundant copies of IFO files, supplied to help in case of corruption. Video players may not allow DVD navigation when IFO or BUP files are absent.

Copy protection

Almost all commercially produced DVD-Video titles use some

restriction Restriction, restrict or restrictor may refer to: Science and technology * restrict, a keyword in the C programming language used in pointer declarations * Restriction enzyme, a type of enzyme that cleaves genetic material Mathematics and log ...

or copy protection method, which also affects VOB files. Copy protection is usually used for copyrighted content. Many DVD-Video titles are encrypted with Content Scramble System (CSS). This is a data encryption and communications authentication method designed to prevent copying video and audio data directly from the DVD-Video discs. Decryption and authentication keys needed for playing back encrypted VOB files are stored in the normally inaccessible lead-in area of the DVD and are used only by CSS decryption software (e.g., in a DVD player or software player). If someone is trying to copy the contents of an encrypted DVD-Video (e.g., VOB files) to a hard drive, an error can occur, because the DVD was not authenticated in the drive by CSS decryption software. Authentication of the disc allows the copying of individual VOB files without error, but the encryption keys will not be copied. If the copied undecrypted VOB files are opened in a player, they will request the keys from the DVD-ROM drive and will fail.DVD Demystified (July 13, 2009
DVD Frequently Asked Questions (and Answers) - Why can't I play movies copied to my hard drive?
Retrieved on 2009-07-28What are the copy protection schemes used in DVD ? What is CSS ?
Retrieved on 2009-07-28 There are many CSS-decrypting programs, or ripping software, such as

libdvdcss libdvdcss (or libdvdcss2 in some repositories) is a free and open-source software library for accessing and unscrambling DVDs encrypted with the Content Scramble System (CSS). libdvdcss is part of the VideoLAN project and is used by VLC media p ...

, DeCSS,

DVD Decrypter DVD Decrypter is a deprecated software application for Microsoft Windows that can create backup disk images of the DVD-Video structure of DVDs. It can be used to make a copy of any DVD protected with Content Scrambling System (CSS). The progra ...

AnyDVD AnyDVD is a device driver for Microsoft Windows which allows decryption of DVDs on the fly, as well as targeted removal of copy preventions and user operation prohibitions (UOPs). With an upgrade, it will also do the same for HD DVD and Blu-r ...

DVD Shrink DVD Shrink is a freeware DVD transcoder program for Microsoft Windows that uses a DVD ripper to back up DVD video. The final versions are 3.2.0.15 (English) and 3.2.0.16 (German); all other versions, such as DVD Shrink 2010, are illegitimate. D ...

which allow a protected DVD-Video disc to be played without access to the original key or copied to hard disk unscrambled. In some countries, their usage can be a violation of law (e.g. for non-personal use).

Playback

A player of generic MPEG-2 files can usually play unencrypted VOB files, which contain MPEG-1 Audio Layer II audio. Other audio compression formats such as AC-3 or DTS are less widely supported.

KMPlayer K-Multimedia Player (commonly known as The KMPlayer, KMPlayer or KMP) is an Adware-supported media player for Windows and iOS that can play most current audio and video formats, including VCD, HDML, DVD, AVI, MKV, Ogg, OGM, 3GP, MPEG-1/2/4, A ...

, VLC media player,

GOM player GOM Player is a media player for Windows, developed by GOM & Company. With more than 100 million downloads, it is also known as the most used player in South Korea. Its main features include the ability to play some broken media files and find ...

, Media Player Classic and more platform-specific

players Players may refer to: Art, entertainment, and media * ''Players'' (1979 film), a film starring Ali MacGraw * ''Players'' (2012 film), a Bollywood film * ''Players'' (Dicks novel), a novel by Terrance Dicks, based on the television series ''Doc ...

like ALLPlayer play VOB files.

Other DVD containers

Some DVD Recorders use

DVD-VR The DVD-VR standard defines a logical format for video recording on DVD-R, DVD-RW, and DVD-RAM style media, including the dual layer versions of these media. As opposed to media recorded with the DVD+VR recording standard, the resulting media are no ...

format and store multiplexed audiovisual content in VRO containers.DVD Demystified (July 13, 2009
What are .IFO, .VOB, .AOB, and .VRO files? How can I play them?
Retrieved on 2009-07-28 A VRO file is equivalent to a collection of DVD-Video VOB files. The VRO files can be played directly like a VOB if no editing is intended.DVD-VR Application format notes
Retrieved on 2009-07-28 Fragmented VRO files are not widely supported by software players and video editing software. Enhanced VOB (EVO) is also an extension to VOB, originally meant for the now-discontinued HD DVD video. It can contain additional video and audio formats such H.264 and

References

External links

doom9.org - What is on a DVD?
{{DEFAULTSORT:Vob DVD Digital container formats Filename extensions