CCITT Group 4

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	|formattype=electronic		|formattype=electronic
	|subcat=Compression		|subcat=Compression
		+	|subcat2=Fax formats
		+	|locfdd={{LoCFDD|fdd000136}}
	|pronom={{PRONOM|x-cmp/15}}		|pronom={{PRONOM|x-cmp/15}}
	}}		}}
		+	[[CCITT Group 4]] is a widely-used lossless compression algorithm for bitonal images. It is also known as '''T6''', '''T.6''', '''Fax4''', '''G4''', '''Group 4''', or '''ITU-T Fax Group 4'''. It is frequently used in [[TIFF]] images created by scanning bitonal images.
−	[[CCITT Group 4]] is a widely used lossless compression algorithm used for bitonal images. It is also known as '''T.6''', '''Fax 4''', and '''ITU-T Fax Group 4'''. It is frequently used in [[TIFF]] images created by scanning bitonal images.	+	It uses [[Modified Modified READ]] (MMR) compression. '''MMR''' is probably another synonym for CCITT Group 4.
−		+
−	It is based on [[Modified Modified READ]] (MMR) compression.	+
	== Related formats ==		== Related formats ==
	In a [[TIFF]] file, compression type 4 is CCITT Group 4.		In a [[TIFF]] file, compression type 4 is CCITT Group 4.
−	In theory, CCITT Group 4 can be used in [[SPIFF]] files (compression type 3).	+	Other formats that can use CCITT Group 4 compression include [[PDF]] and [[SPIFF]].
	== See also ==		== See also ==
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	== Specifications ==		== Specifications ==
	* [http://www.itu.int/rec/T-REC-T.6-198811-I/en T.6 : Facsimile coding schemes and coding control functions for Group 4 facsimile apparatus]		* [http://www.itu.int/rec/T-REC-T.6-198811-I/en T.6 : Facsimile coding schemes and coding control functions for Group 4 facsimile apparatus]
		+
		+	== Software ==
		+	* [[Farbfeld Utilities]]
		+	* [[ImageMagick]] (specify the file format as "GROUP4")
	== References ==		== References ==
	* [http://www.digitalpreservation.gov/formats/fdd/fdd000136.shtml ITU-T Group 4 FAX Compression (T.6), from Library of Congress resource on Sustainability of Digital Formats]		* [http://www.digitalpreservation.gov/formats/fdd/fdd000136.shtml ITU-T Group 4 FAX Compression (T.6), from Library of Congress resource on Sustainability of Digital Formats]
		+
		+	[[Category:Graphics]]
		+	[[Category:Fax]]

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Latest revision as of 01:33, 25 August 2020

File Format
Name	CCITT Group 4
Ontology	Electronic File Formats Compression Fax formats CCITT Group 4
LoCFDD	fdd000136
PRONOM	x-cmp/15

CCITT Group 4 is a widely-used lossless compression algorithm for bitonal images. It is also known as T6, T.6, Fax4, G4, Group 4, or ITU-T Fax Group 4. It is frequently used in TIFF images created by scanning bitonal images.

It uses Modified Modified READ (MMR) compression. MMR is probably another synonym for CCITT Group 4.

Contents 1 Related formats 2 See also 3 Specifications 4 Software 5 References

[edit] Related formats

In a TIFF file, compression type 4 is CCITT Group 4.

Other formats that can use CCITT Group 4 compression include PDF and SPIFF.

[edit] See also

• CCITT Group 3

[edit] Specifications

• T.6 : Facsimile coding schemes and coding control functions for Group 4 facsimile apparatus

[edit] Software

• Farbfeld Utilities
• ImageMagick (specify the file format as "GROUP4")

[edit] References

• ITU-T Group 4 FAX Compression (T.6), from Library of Congress resource on Sustainability of Digital Formats