AUDIO TITLE SET folder: The AUDIO_TS folder is a part of the original DVD-Video specification and is not populated with files in a DVD-Video disc. DVD Authoring software packages still generate this folder. It is used primarily in the DVD-Audio disc format.

VIDEO TITLE SET folder: The VIDEO_TS folder must be at the top or root directory level of the DVD-Video disc. If other folders and files exist at the root level, they are related to enhanced features provided on the disc and make the disc a "Hybrid DVD" (see below).

• Contains the various Title Sets (VTS) for a DVD-Video.
• A VTS represents a "Title," which is a movie or track on a DVD-Video.
• The VIDEO_TS folder also contains information about the navigation structure for the disc and its menus/scripting.
• The VIDEO_TS folder is the one used to play back and test the "image" of a DVD-Video before burning the content to a DVD-R.
• The VIDEO_TS folder can contain many Video Title Sets. Usually, one Video Title Set represents the main movie. Other Video Title Sets represent supplementary materials, movie trailers, filmographies, etc.
• A VTS consists of three files, VOB, IFO, and BUP.

PRESENTATION FILES: The VOB file of a VTS contains the multiplexed menus, audio, video, and subtitle streams for a Title. These are the presentation or displayed contents for a DVD-Video. Under normal conditions, one cannot de-multiplex the menus, audio, video and subtitle streams in order to de-construct or change the content. Re-authoring and re-multiplexing is required.

There is a tool created by Trai Forrester called TFDVDEdit. One of its features is a VOB Editor. It lets you edit everything in a project's multimplexed VOB files (this is where the menus, video, audio and subpictures reside on the finished DVD).

A VOB can be no larger than 1GB and spills over into another VOB of another VTS if necessary.

NAVIGATION FILES: The IFO file of a VTS contains the navigation instructions, including jumps, programs and button definitions. It also contains the set up options such as aspect ratio and language selection. An IFO can be no larger than 1GB and spills over into another IFO of another VTS if necessary.

BACKUP FILES: The BUP file of a VTS is a duplicate of the IFO file for that set. This duplicate is used to avoid data being lost through scratches or errors on the DVD-Video disc. The BUP is usually physcially located on the outside rings of the DVD, far away from its original.

HYBRID DVD FILES: If the DVD contains supplementary enhanced content, such as games and web accessibility, then these files are contained at the top most directory structure. These files are often specific to a computer platform (see Web-DVD).