Maximum VOB Files in a Video Title Set

This article explains the technical limitations on split Video Object (VOB) files within a single Video Title Set (VTS) under the DVD-Video specification. A standard DVD-Video layout enforces strict file-naming conventions and file-size caps to maintain compatibility across legacy operating systems and standalone players. Readers will learn the exact number of content and menu VOB files allowed per title set, the reasoning behind the split limit, and how DVD authoring handles content that exceeds these constraints.

In a single Video Title Set, the maximum number of split content VOB files permitted is 9.

Under the DVD-Video specification, content files are named following the pattern VTS_xx_y.VOB, where xx represents the title set number (from 01 to 99) and y represents the individual file sequence number:

• Menu VOB (VTS_xx_0.VOB): The index 0 is reserved exclusively for the menu of that specific title set. It cannot be split; there is only ever a maximum of one menu VOB per VTS.
• Content/Title VOBs (VTS_xx_1.VOB through VTS_xx_9.VOB): The indices 1 through 9 are assigned to the actual video and audio content.

Because the specification only allocates a single digit for the sequence number y, a single title set cannot exceed VTS_xx_9.VOB. Including the optional menu file, the absolute maximum number of total VOB files of any kind in a single VTS is 10 (one menu VOB plus nine content VOBs).

This splitting mechanism exists because DVD filesystems (UDF 1.02 and MicroUDF) require individual files to remain below 1 GiB (1,073,741,824 bytes, or 1.024 GB) to ensure compatibility with 32-bit file systems such as FAT32. Consequently, a single continuous video title cannot exceed roughly 9 GiB across its 9 split files.

If a video project requires more capacity or exceeds 9 content VOB files, the author must divide the content across multiple Video Title Sets. The DVD standard allows up to 99 separate Video Title Sets (VTS_01 through VTS_99) on a single disc, controlled by the global Video Manager (VIDEO_TS.IFO).