What is the MOI file format?
A .moi file, also known as a Movie Index file, is created alongside the video file, which is saved with a .MOD extension. When an application opens the .mod file for playback or editing, the corresponding .moi is read automatically to supply clip metadata.
.moi is not a video or audio stream - it is a small binary sidecar produced by JVC Everio and Panasonic SD/HDD camcorders, typically just a few hundred bytes to a few KB. The file stores the recording date and time, clip duration in milliseconds, aspect ratio, TV system, and audio codec (AC-3 or MPEG). Multi-byte fields use big-endian byte order; the file begins with a version stamp such as V6 at offset 0.
The format was superseded by AVCHD, which embeds metadata within the stream itself. To watch the footage, open the .mod video - not the .moi index.
Security & safety
RISK: LOWA .MOI is a tiny passive metadata record with no executable content - completely harmless. The only thing to know is practical, not security: it isn't video/audio, so don't waste effort trying to 'play' or 'convert' it. After copying footage off a camcorder you can usually delete the .MOI files safely; you only lose the camcorder software's view of the original recording date. Keep them only if you rely on Everio MediaBrowser / VideoCam Suite for dates.
Format details
in a nutshellPrograms that open MOI files
Windows3 apps
Hex editor (HxD)
Free Open the .MOI in a hex editor only if you need to inspect the raw metadata fields. There's no 'viewer' - the file is an index, not media.
JVC Everio MediaBrowser (legacy)
Built-in The camcorder's bundled software reads the .MOI alongside its .MOD to show the clip's date/length. Largely legacy; downloads often unavailable.
VLC media player (for the .MOD, not the .MOI)
Open-source To watch the actual video, open the matching .MOD file in VLC. The .MOI itself is not playable. 
macOS1 app
Hex editor (Hex Fiend)
Open-source Inspect the raw .MOI metadata fields if needed. To play the footage, open the sibling .MOD in VLC. 
Linux1 app
Hex editor / xxd
Open-source 'xxd clip.MOI | less' to inspect the metadata bytes. Play the matching .MOD with VLC/ffplay. Technical details
deep spec| Format type | Fixed-offset binary sidecar (index record, not a media stream) |
| Companion video format | Paired one-to-one with a same-named `.MOD` or `.TOD` video clip |
| Typical file size | A few hundred bytes to a few KB - it indexes the clip, not the media itself |
| Byte order | Big-endian for all multi-byte fields |
| File signature (magic bytes) | Version stamp at offset 0 - commonly ASCII "V6" (hex 56 36) |
| Duration field | Clip length stored in milliseconds at byte offsets 0x0E-0x11 |
| Date/time field | Recording date and time encoded at offsets 0x06-0x0C |
| Aspect ratio / TV system | Stored in a 4-byte field at offsets 0x80-0x83 |
| Audio codec identifier | 2-byte field at offset 0x84: 0x00C1 = AC-3 (Dolby Digital), 0x4001 = MPEG audio |
| Audio bitrate field | Stored at offset 0x86 |
| Compression | None - raw binary fields with no data compression |
| Developer | JVC and Panasonic (tapeless camcorder vendors, introduced circa 2003) |
| Associated camcorder lines | JVC Everio GZ-series; Panasonic SD/HDD camcorder models |
| Superseded by | AVCHD (`.MTS`/`.M2TS`), which embeds metadata in the stream with no separate sidecar |
| MIME type | application/octet-stream (no dedicated MIME type registered) |
| Released | circa 2003 (JVC Everio GZ-series and Panasonic SD/HDD camcorders) |
| Latest version | N/A (de facto vendor format; superseded by AVCHD .MTS, which has no separate index sidecar) |
| Specification | en.wikipedia.org |
MOI conversions
Community Q&A
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