File Extension DJVU
File extension DjVu is a file format used to store compressed documents which include images, text, drawings and photographs. To open DjVu files you can use SumatraPDF software for Windows, Cuminas Official DjVu Browser Plug-in, DjVuLibre DjView, WinDjView and MacDjView Desktop Viewers.
DjVu documents are optimized for storing OCRed (Optical Character Recognized) documents and allow storage of text layer on top of original text image.
Developers can use an open source library distributed as part of DjVuLibre package. DjVu file structure is based on IFF (Interchangeable File Format). File starts with 4-byte "AT&T" magic number. Thus if you open DjVu file in text or hex editor you should see "AT&T" as 4 first bytes of the file.
DjVu is an open source document format with patents. It is maintained by original DjVu developers as an open source library DjVuLibre under the GNU General Public License. Commercial developmen rights for the DjVu are owned by several companies which include AT&T Corporation, LizardTech, Cuminas and Celartem.