Can DVD-Audio Discs Use VOB Files?

While the core audio of a DVD-Audio disc is stored in the AUDIO_TS directory using Audio Object (.AOB) files, DVD-Audio discs can and frequently do utilize Video Object (.VOB) files inside a complementary VIDEO_TS directory. This hybrid structure is formally supported by the DVD-Audio specification to enable backward compatibility with standard DVD-Video players and to provide video menus, still images, or accompanying video content.

The Role of AUDIO_TS vs. VIDEO_TS

A compliant DVD-Audio disc contains two primary root directories: AUDIO_TS (Audio Title Set) and VIDEO_TS (Video Title Set).

• The AUDIO_TS Directory: This folder is dedicated strictly to DVD-Audio players. High-resolution audio streams—such as stereo or multi-channel Meridian Lossless Packing (MLP) and uncompressed high-bitrate LPCM—are stored in .AOB files. These are technically modified MPEG-2 Program Streams tailored for audio. The AUDIO_TS directory itself strictly uses .AOB, .IFO, and .BUP extensions, meaning standard .VOB files are not placed directly inside this folder.
• The VIDEO_TS Directory: This folder houses standard DVD-Video architecture using .VOB, .IFO, and .BUP files.

Why DVD-Audio Discs Include VOB Files

Most commercial DVD-Audio releases are authored as "Universal DVD" or hybrid discs. Including .VOB files in the VIDEO_TS zone serves several practical functions:

1. Backward Compatibility: Standard DVD-Video players cannot interpret the .AOB files in AUDIO_TS. To ensure the disc remains playable on any device, authors place alternate, video-compatible audio formats (such as Dolby Digital AC-3, DTS, or standard 16-bit/48kHz PCM) inside .VOB containers within the VIDEO_TS folder.
2. Interactive Visual Menus: While dedicated DVD-Audio players can render basic visual menus directly from the audio zone, authoring the navigation menus as standard video streams in .VOB format provides cross-platform menu functionality.
3. Bonus Video Content: Music videos, artist interviews, and liner notes are authored as conventional DVD-Video content and stored as .VOB files.

Within the strict confines of the AUDIO_TS folder, VOB files are not used; the architecture mandates .AOB files instead. However, in the broader directory structure of a complete DVD-Audio disc, .VOB files are fully supported, standard, and widely utilized to bridge the gap between high-resolution audio hardware and standard video players.