What is the BUP file format?
A .bup file contains a backup copy of an .IFO navigation file for a given DVD disc. .BUP files are used when the corresponding .ifo file is corrupted or unreadable. A .bup file stores all the data needed for playing and navigating the disc's contents:
- Menu information
- Playback information
- Audio track data and information
- Chapter data
- Subtitles data
DVD-Video discs store .bup files in the VIDEO_TS folder alongside .VOB video object files. Together these files constitute a DVD-Video structure with interactive menus. The .bup is an exact byte-for-byte duplicate of its paired .ifo - VIDEO_TS.BUP backs up VIDEO_TS.IFO, and each VTS_xx_0.BUP backs up its matching VTS_xx_0.IFO. If both .ifo and .bup files are absent from a disc, it cannot be navigated with a DVD player. When an .ifo file is damaged, renaming the .bup file to .ifo can restore full disc navigation.
Security & safety
RISK: LOWDVD BUP files are inert navigation data - they contain no executable code and cannot harm a system. The only real caution is housekeeping: don't delete BUP files from a DVD backup you want to keep playable, since they are the disc's fallback navigation. A .bup of unknown origin is worth a quick header check (a DVD BUP begins with "DVDVIDEO-VMG/VTS") before assuming what it is.
Format details
in a nutshell- McAfee Quarantine File - VirusScan/Trellix stores detected threats as .bup OLE compound files with XOR-obfuscated (key 0x6A) members; restore only via the product's Quarantine Manager.
- Generic application backup - Some games and editors write automatic backups named .bup with no shared structure.
Programs that open BUP files
Windows2 apps
VLC media player
Open-source Don't open the BUP itself - Media → Open Folder and pick the VIDEO_TS folder (or open the largest VOB). The BUP/IFO provide menus and chapters. 
macOS1 app
VLC media player
Open-source Open the VIDEO_TS folder in VLC; the BUP is used automatically if the IFO is damaged. 
Linux1 app
Technical details
deep spec| Format type | Binary; byte-for-byte identical copy of a DVD-Video `.IFO` navigation file |
| File signature | `DVDVIDEO-VMG` at byte offset 0 (`VIDEO_TS.BUP`) or `DVDVIDEO-VTS` at byte offset 0 (`VTS_xx_0.BUP`) |
| Byte order | Big-endian, matching the DVD-Video IFO binary structure |
| MIME type | `application/octet-stream` |
| Storage location | `VIDEO_TS` folder on the DVD-Video disc |
| Naming pattern | `VIDEO_TS.BUP` for the disc menu set, or `VTS_xx_0.BUP` for each title set (xx = 01-99) |
| Paired file | Each `.bup` is paired 1:1 with a same-named `.ifo`; both files are identical in size and content |
| Backup trigger | DVD player falls back to the `.bup` automatically when the primary `.ifo` fails its checksum or is unreadable |
| Typical file size | Identical to its paired `.ifo` - a few kilobytes to several megabytes depending on the title set |
| Reuse as IFO | Renaming `.bup` to `.ifo` is a standard recovery technique when the original navigation file is corrupted |
| Contents | Navigation structures including title sets, chapter points, audio and subtitle stream mappings, menu program chains, and video attributes |
| Developer | DVD Forum (defined in the DVD-Video specification, introduced 1996) |
| Typical count per disc | One `VIDEO_TS.BUP` plus one `VTS_xx_0.BUP` per title set; a standard single-title disc has 2-3 `.bup` files |
| Released | 1996 (DVD-Video specification) |
BUP conversions
Community Q&A
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