About the Jbig file format
- Name
- Joint Bi-level Image Experts Group
- Extension
- .jbig
- Format
- Binary
- Category
- Raster Image
- Developer
- Joint Bi-level Image Experts Group (JBIG)
- Description
- JBIG is a lossless compression file format that was created for the fax machine; it can be used by other image file formats. The files created by JBIG format are smaller compared to G3 and G4 file formats.
- MIME Type
- image/jbig
- Sample
- sample.jbig
- Wikipedia
- .jbig on Wikipedia
Invented by the Joint Bi-level Image Experts Group, JBIG is an early lossless image compression standard. It was standardized as ISO/IEC standard 11544 and as ITU-T recommendation T.82 in March 1993 and is widely implemented in fax machines. However, a newer bi-level image compression standard JBIG2 was released therefore changing JBIG to JBIG1. It uses the file extension .jbg or .jbig
JBIG1 was designed for compression of binary images, faxes in particular, but can also be used on other images. In most instances, it offers a 20 - 50% increase in compression efficiencies compared to the Fax Group 4 standard. In other situations, it offers a 30-fold compression improvement.
JBIG1 is based on a form of arithmetic coding developed by IBM – Q-coder. It uses a relatively minor refinement invented by Mitsubishi, therefore resulting in what is known as the QM-coder. It concentrates the probability of each encoded bit on the values of the previous bits and the values in the previous line of the picture. It also supports progressive transmission which generally incurs a small overhead in bit rate, around 5%.
The codec was not widely implemented in open-source software due to skepticism on the patent license requirements for its implementations by IBM, Mitsubishi, and AT&T. As of 2012, none of the commonly used web browsers supported it and since then, there are no more JBIG1 patents in force. The last patents to expire were those of Mitsubishi in Canada and Australia on February 25, 2011, and in the United States on April 4, 2012.