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TIFF Tag YCbCrSubSampling

IFDImage
Code530 (hex 0x0212)
NameYCbCrSubSampling
LibTiff nameTIFFTAG_YCBCRSUBSAMPLING
TypeSHORT
Count2
Default[2,2]

Description

Specifies the subsampling factors used for the chrominance components of a YCbCr image.

The two fields of this field, YCbCrSubsampleHoriz and YCbCrSubsampleVert, specify the horizontal and vertical subsampling factors respectively.

The two fields of this field are defined as follows:

Short 0: YCbCrSubsampleHoriz:
1 = ImageWidth of this chroma image is equal to the ImageWidth of the associated luma image.
2 = ImageWidth of this chroma image is halfthe ImageWidth of the associated luma image.
4 = ImageWidth of this chroma image is one-quarter the ImageWidth of the associated luma image.

Short 1: YCbCrSubsampleVert:
1 = ImageLength (height) of this chroma image is equal to the ImageLength of the associated luma image.
2 = ImageLength (height) of this chroma image is half the ImageLength of the associated luma image.
4 = ImageLength (height) of this chroma image is one-quarter the ImageLength of the associated luma image.

Both Cb and Cr have the same subsampling ratio. Also, YCbCrSubsampleVert shall always be less than or equal to YCbCrSubsampleHoriz.

ImageWidth and ImageLength are constrained to be integer multiples of YCbCrSubsampleHoriz and YCbCrSubsampleVert respectively. TileWidth and TileLength have the same constraints. RowsPerStrip must be an integer multiple of YCbCrSubsampleVert.

The TIFF-F specification (RFC 2301) renames this tag to 'ChromaSubSampling' to reflect extended applicability to other color spaces.

Related tags

YCbCrCoefficients
YCbCrPositioning

See also

RFC 2301 - File Format for Internet Fax