File Extension VOB
File extension VOB most commonly refers to a DVD Video Object file, and is one of the most widespread formats used to store video and audio streams on DVD discs. The VOB format also may denote a Vue d'Esprit object, which is a 3D model created for use within the application.
DVD VOB files are a container, which consist of video, audio and subtitle streams. The video stream is in MPEG-2 format, whilst the audio can be in AC3, MPEG-2 multichannel, MPEG-1 Layer 2 dual channel or PCM format. The vast majority of VOB files contain an AC3 audio stream as it offers a good compromise between quality and bitrate. PCM (Pulse-Code Modulation) streams are used on occasions where high-quality audio is the primary objective, such as on music DVDs, though given their uncompressed nature and inevitably large file sizes, are not often used for film soundtracks.
VOB files often contain audio tracks and subtitles in multiple languages, which are usually streamed alongside the video. Though this creates a higher bandwidth demand, it does make it possible to switch between streams during playback. It is also common to find a DVD consisting of multiple VOB files, whereby each individual file represents a single scene or chapter. This allows easy navigation through the contents of a DVD, as the playback software can simply skip to the beginning of the desired VOB file. In many cases, an File extension IFO file accompanies the VOB file which contains menu information as well as the location of each chapter, particularly in cases where the VOB file is not split.
Most DVD playing software can open VOB files, and popular applications include CyberLink PowerDVD, Windows Media Player, VLC Media Player and InterVideo WinDVD. DVD creation software such as Nero and Roxio are also able to import VOB files and burn them to disc.