|Extension TIFF Tag YCbCrSubSampling|
TIFF Tag Reference
TIFF Tag YCbCrSubSampling
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:
Short 1: YCbCrSubsampleVert:
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.