VOB (Video Object) is a container format in DVD-Video media. VOB file contains digital video, digital audio, subtitles, screen menus and navigation all multiplexed into a single stream. The .VOB files are typically stored in the VIDEO_TS folder of a DVD and are based on the MPEG program stream format.

On the DVD all the content for one set is contiguous, but broken into 1GB VOB files for the convenience of the various operating systems. Every file must be less than or equal to 1 GB size.

Many DVDs are encrypted with Content Scramble System (CSS), a data encryption method, designed to prevent direct copying of video and audio from the DVD disc.