Microsoft Document Imaging Format
| Filename extension |
.mdi |
|---|---|
| Internet media type |
image/vnd.ms-modi |
| Magic number | 0x5045 |
| Developed by | Microsoft |
| Type of format | Image file formats |
| Extended from | TIFF |
MDI (Microsoft Document Imaging format) is a file format created by Microsoft for storing raster images of scanned documents together with optional annotations or metadata which can include the text of the document, generated by OCR. MDI is a proprietary format - the specifications have not been made public by Microsoft, and MDI files can only be produced or read by certain Microsoft software, in particular the Microsoft Office Document Imaging (MODI) module included in Microsoft Office 2003 and later versions. With MDI being a raster format it is by far inferior to PDF. The latter can include fonts/vector graphic information to produce high quality and scalable document and graphic representations.
Relation to TIFF
It is known that MDI is a variant of TIFF (see Brad Hards references below). Key differences from TIFF:
- Magic number is 0x5045 (ASCII 'EP'?) (instead of 0x4D4D 'MM' or 0x4949 'II').
- Three proprietary image compression formats are used.
- Numerous proprietary tag values are used.