What Are Audio TS & Video TS?by Finn McCuhil
When a disc is inserted into a DVD player, the player's firmware is programmed to search for two data folders. The first is labeled "VIDEO_TS." The second is labeled "AUDIO_TS." For a disc containing a movie to play in a standard DVD player, the "VIDEO_TS" folder must be present. In some players, the "AUDIO_TS" folder must also be present or the player will not recognize the disc as valid media.
The final two characters of the "VIDEO_TS" and "AUDIO_TS" folder names stand for "Title Set," signifying the type of files the player looks for in each folder. So, the player expects to find video files in the "VIDEO_TS" folder and audio files in the "AUDIO_TS" folder.
DVDs that contain movie information will have files with the extensions IFO, BUP and VOB in the "VIDEO_TS" folder. Files with the IFO extension contain information that allows the player to reference specific chapters, subtitles and audio tracks. Files with the BUP extension are backup files for the IFO files. These backup files allow the disc to play if the area containing a related IFO file is damaged. Files with the VOB -- video object -- extension contain the video, audio, subtitle and menu data that's decoded by the player and displayed on the screen.
Even though a DVD must contain an "AUDIO_TS" folder to be recognized by all DVD players, this folder usually contains no files or information. It can be used for special features or subtitles. When files are present in the "AUDIO_TS" folder, the files will have the same IFO, BUP and VOB extensions as the "VIDEO_TS" folder files.
When a DVD is inserted into a player, the player first looks for and reads the "VIDEO_TS.IFO" -- video title set information -- file in the "VIDEO_TS" folder. The information contained in this file tells the player where to locate and how to process the information in the "VIDEO_TS.VOB" -- video title set visual object -- file. Video object files larger than 1GB are split into smaller files or chapters. Files with information for each chapter carry the same file name with differing extensions, like "VTS_01_0.VOB," "VTS_01_0.IFO" and "VTS_01_0.BUP."
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