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. No ...

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- ...

media. VOB can contain

digital video Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data Digital data, in information theory and information systems, is information represented as a string of discrete symbols eac ...

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, samp ...

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 informa ...

, DVD menus and navigation contents

multiplexed In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource - a ...

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 ...

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 MPEG-1 Audio Layer II or MPEG-2 Audio Layer II (MP2, sometimes incorrectly called Musicam or MUSICAM) is a lossy audio compression format defined by ISO/IEC 11172-3 alongside MPEG-1 Audio Layer I and MPEG-1 Audio Layer III (MP3). While MP3 is m ...

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 Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the am ...

, 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 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 t ...

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 logi ...

copy protection Copy protection, also known as content protection, copy prevention and copy restriction, describes measures to enforce copyright by preventing the reproduction of software, films, music, and other media. Copy protection is most commonly found o ...

method, which also affects VOB files. Copy protection is usually used for

copyrighted A copyright is a type of intellectual property that gives its owner the exclusive right to copy, distribute, adapt, display, and perform a creative work, usually for a limited time. The creative work may be in a literary, artistic, education ...

content. Many DVD-Video titles are

encrypted In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can deci ...

with

Content Scramble System The Content Scramble System (CSS) is a digital rights management (DRM) and encryption system employed on many commercially produced DVD-Video discs. CSS utilizes a proprietary 40-bit stream cipher algorithm. The system was introduced around 1996 ...

(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 A DVD player is a device that plays DVDs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. Some DVD players will also play audio CDs. DVD players are connected to a television to ...

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 Ripping is extracting all or parts of digital content from a container. Originally, it meant to rip music out of Commodore 64 games. Later, the term was used to extract WAV or MP3 format files from digital audio CDs, but got applied as well to e ...

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 DeCSS is one of the first free computer programs capable of decrypting content on a commercially produced DVD video disc. Before the release of DeCSS, open source operating systems (such as BSD and Linux) could not play encrypted video DVDs. ...

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 progr ...

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. DV ...

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,

VLC media player VLC media player (previously the VideoLAN Client and commonly known as simply VLC) is a free and open-source, portable, cross-platform media player software and streaming media server developed by the VideoLAN project. VLC is available for desk ...

, GOM player,

Media Player Classic Media Player Classic (MPC), Media Player Classic - Home Cinema (MPC-HC), and Media Player Classic - Black Edition (MPC-BE) are a family of free and open-source, compact, lightweight, and customizable media players for 32-bit and 64-bit Microsoft ...

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 ...

ALLPlayer ALLPlayer is a cross-platform media player (software), media player and streaming media Server (computing), server written by ALLPlaye Group Ltd. ALLPlayer is available for desktop Windows and mobile platforms, such as Android (operating system) ...

play VOB files.

Other DVD containers

Some

DVD Recorder A DVD recorder is an optical disc recorder that uses optical disc recording technologies to digitally record analog or digital signals onto blank writable DVD media. Such devices are available as either installable drives for computers o ...

s 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 n ...

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 Enhanced Video Object, also known as Enhanced VOB, EVOB or EVO, is a container format for HD DVD video media. It contains the actual digital video, digital audio, subtitle and DVD menu contents in stream form. It is an extension to VOB. It can co ...

(EVO) is also an extension to VOB, originally meant for the now-discontinued

HD DVD HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to the ...

video. It can contain additional video and audio formats such

H.264 Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 Part 10, is a video compression standard based on block-oriented, motion-compensated coding. It is by far the most commonly used format for the recording, compression, and distr ...

and AAC.

References

External links

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