CCITT Group 3
(→Related formats) |
|||
| Line 25: | Line 25: | ||
== Software == | == Software == | ||
| + | * [[Konvertor]] | ||
* [[Netpbm]]: g3topbm, pbmtog3 | * [[Netpbm]]: g3topbm, pbmtog3 | ||
* [[ImageMagick]] (format named "FAX") | * [[ImageMagick]] (format named "FAX") | ||
Revision as of 14:42, 22 February 2016
CCITT Group 3 is a lossless compressed data format for bi-level images. It is also known as T4, T.4, Fax3, Group 3, G3, or ITU-T Fax Group 3. It is one of the formats used by fax machines. It is usually embedded in another image file format such as TIFF, but can be stored in a file by itself.
It comes in two main varieties: so-called 1-dimensional and 2-dimensional (though both are used on 2-dimensional images). The 1-dimensional variety uses Modified Huffman (MH) compression, and the 2-dimensional variety uses Modified READ (MR) compression.
Contents |
Related formats
Many of the formats listed in the Fax formats article use CCITT Group 3 compression.
In a TIFF file, compression codes 2, 3, and 32771 are varieties of CCITT Group 3 compression.
Other formats that can use CCITT Group 3 compression include PDF and SPIFF.
See also
Specifications
- ITU-T Recommendation T.4
- TIFF 6.0 Specification, Section 10: Modified Huffman Compression
Software
- Konvertor
- Netpbm: g3topbm, pbmtog3
- ImageMagick (format named "FAX")
