Template:IFD tag Compression

Compression (scheme used on the image data)

Tag = 259 (103.H)

Type = SHORT

N= 1

Default		1 (No compression)

The specification defines these values to be baseline:

1 = No compression 2 = CCITT modified Huffman RLE 32773 = PackBits compression, aka Macintosh RLE

Additionally, the specification defines these values as part of the TIFF extensions:

3 = CCITT Group 3 fax encoding 4 = CCITT Group 4 fax encoding 5 = LZW 6 = JPEG ('old-style' JPEG, later overriden in Technote2)

Technote2 overrides old-style JPEG compression, and defines:

7 = JPEG ('new-style' JPEG)

Adobe later added the deflate compression scheme:

8 = Deflate ('Adobe-style')

The TIFF-F specification (RFC 2301) defines:

9 = Defined by TIFF-F and TIFF-FX standard (RFC 2301) as ITU-T Rec. T.82 coding, using ITU-T Rec. T.85

(which boils down to JBIG on black and white).

10 = Defined by TIFF-F and TIFF-FX standard (RFC 2301) as ITU-T Rec. T.82 coding, using ITU-T Rec. T.43

(which boils down to JBIG on color).

LibTiff supports most of these. (Even though it can be argued that old-style JPEG cannot be really

properly supported, and is probably best ignored, there is some attempt at decoding support for some

common old-style JPEG interpretations.) Additionally, LibTiff adds support for some compression schemes

that are not part of the specification and are somewhat less common. Here's LibTiff's definition of

possible values:

COMPRESSION_NONE = 1; COMPRESSION_CCITTRLE = 2; COMPRESSION_CCITTFAX3 = COMPRESSION_CCITT_T4 = 3; COMPRESSION_CCITTFAX4 = COMPRESSION_CCITT_T6 = 4; COMPRESSION_LZW = 5; COMPRESSION_OJPEG = 6; COMPRESSION_JPEG = 7; COMPRESSION_NEXT = 32766; COMPRESSION_CCITTRLEW = 32771; COMPRESSION_PACKBITS = 32773; COMPRESSION_THUNDERSCAN = 32809; COMPRESSION_IT8CTPAD = 32895; COMPRESSION_IT8LW = 32896; COMPRESSION_IT8MP = 32897; COMPRESSION_IT8BL = 32898; COMPRESSION_PIXARFILM = 32908; COMPRESSION_PIXARLOG = 32909; COMPRESSION_DEFLATE = 32946; COMPRESSION_ADOBE_DEFLATE = 8; COMPRESSION_DCS = 32947; COMPRESSION_JBIG = 34661; COMPRESSION_SGILOG = 34676; COMPRESSION_SGILOG24 = 34677; COMPRESSION_JP2000 = 34712;