Details: File format summary

Details for: CCITT T.4


Compression Name	CCITT T.4
Other names	CCITT Group 3
Identifier(s)	PUID: x-cmp/14
Family
Description	Officially known as CCITT T.4, Group 3 is a compression algorithm developed by the International Telegraph and Telephone Consultative Committee in 1985 for encoding and compressing 1-bit (monochrome) image data. Its primary use has been in fax transmission, and it is optimised for scanned printed or handwritten documents. Group 3 is a lossless algorithm, of which two forms exist: one-dimensional (which is a modified version of Huffman encoding) and two-dimensional, which offers superior compression rates. Due to its origin as a data transmission protocol, Group 3 encoding incorporates error detection codes. Group 3 compression is most commonly used in the TIFF file format.
Lossiness	Lossless
Released	01 Jan 1985
Withdrawn
Developed by	International Telecommunication Union
Supported by
Documentation	CCITT Blue Book, 1989, Volume VII, Fascicle VII.3: Terminal equipment and protocols for telematic services, recommendations T.0 - T.63
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