When you insert a video DVD into your computer, you can open the DVD and view the contents just like a folder on your hard drive. Most video DVDs have two folders in the root directory – AUDIO_TS and VIDEO_TS. These names are short for "audio transport stream" and "video transport stream."

The AUDIO_TS folder is used for storing audio data for DVD-audio discs. If the DVD contains only video content, the AUDIO_TS folder will be empty. Therefore, most DVDs have an empty AUDIO_TS folder.

The VIDEO_TS folder contains all the DVD's video data and playback information. A typical VIDEO_TS folder may look something like the folder below:

The .VOB (video object) files contain the majority of the DVD data. This includes the actual video and audio data as well as subtitles, additional viewing angles, and other video-related data. VOB files can be a maximum of 1 GB in size, which is why multiple VOB files are often required to create a video DVD. Some programs can extract video data from VOB files or play back the video data directly.

The .IFO (information) files contain basic information about the DVD and the corresponding VOB files. This includes what data should be loaded when the DVD is first inserted, where the DVD chapter markers are located, and what DVD commands can be entered by the user.

The .BUP (backup) files are exact copies of the IFO files. The serve as backups in case the original IFO files become corrupted and cannot be read. Since the DVD cannot be played back without valid information files, the BUP files reduce the risk of a small error or scratch on the disc ruining the DVD.