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. Nota ...

DVD-Video DVD-Video is a consumer video format used to store digital video on DVDs. DVD-Video was the dominant consumer home video format in most of the world in the 2000s. As of 2024, it competes with the high-definition Blu-ray Disc, while both rece ...

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 signal (signal processing), digital form. In digital audio, the sound wave of the audio signal is typically encoded as numerical sampling (signal processing), ...

subtitles Subtitles are texts representing the contents of the audio in a film, television show, opera or other audiovisual media. Subtitles might provide a transcription or translation of spoken dialogue. Although naming conventions can vary, caption ...

, 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— ...

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 directory at the root of a

DVD The DVD (common abbreviation for digital video disc or digital versatile disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any ki ...

. The VOB format is based on the

MPEG program stream Program stream (PS or MPEG-PS) is a container format (digital), 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 ...

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 MPEG-1 is a standard for lossy compression of video and audio. It is designed to compress VHS-quality raw digital video and CD audio down to about 1.5 Mbit/s (26:1 and 6:1 compression ratios respectively) without excessive quality loss, m ...

video,

MPEG-1 Audio Layer II MP2 (formally MPEG-1 Audio Layer II or MPEG-2 Audio Layer II, sometimes incorrectly called Musicam) is a lossy audio compression format. It is standardised as one of the three audio codecs of MPEG-1 alongside MPEG-1 Audio Layer I (MP1) and 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 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 amplitud ...

, 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 * Airborne aircraft carrier, a type of aircraft * Alaskan Air Command, a radar network * American Aeronautical Corporation, a company from Port Washington, New ...

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 ...

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 or

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

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

copyright A copyright is a type of intellectual property that gives its owner the exclusive legal 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, ...

ed content. Many DVD-Video titles are

encrypted In cryptography, encryption (more specifically, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the information, known as plain ...

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 ...

(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 machine 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 the extraction of digital content from a container, such as a CD, onto a new digital location. Originally, the term meant to rip music from Commodore 64 games. Later, the term was applied to ripping WAV or MP3 files from digital audio ...

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, free and open source operating systems (such as BSD and Linux) could not play encrypted video ...

DVD Decrypter DVD Decrypter is a 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 program can als ...

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-ray ...

DVD Shrink DVD Shrink is a freeware DVD transcoder program for Microsoft Windows that uses a DVD ripper to back up DVD video. It can also be run under Linux using Wine. The final versions are 3.2.0.15 (English) and 3.2.0.16 (German); all other versio ...

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) is a free and open-source software, free and open-source, software portability, portable, cross-platform media player software and streaming media Server (computing), server developed by the Vide ...

GOM player GOM Player is a media player for Microsoft 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 ...

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- and 64-bit Microsoft Wi ...

and more platform-specific players like ALLPlayer play VOB files.

Other DVD containers

Some

DVD Recorder A DVD recorder is an optical disc recorder that uses optical disc recording technologies to digital recording, digitally record analog signal, analog or Digital signal (signal processing), digital signals onto blank writable DVD recordable, D ...

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 ...

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 HD DVD (short for High Density Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video.

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