Greetings,
I wanted to know if libtiff supports YCbCr subsampled
planar images? Is it planned, i think it would be good to support it , I
tried to use an older version of the library 3.6.1 and it seems it is
not supported.
Rationale: A common issue when doing video encoding is that we need to
prepare the images in the YCbCr color space. Encoding is usually in
planar format, such as 4:2:2 or 4:2:0 or event 4:1:0 subsampled with
different matrixes with studio or full range. I do not know of any image
format that permits to support different subsampling, planar data,
custom matrixes and subsampling position information and compression
except for the TIFF format. Hence I have my image encoder when doing
YCbCr image space encodes directly in planar format, not in packed
format with full LZW and predictor information which requires less
processing. Furthermore, when decoding images from movies, we can dump
the images in a TIFF file, with one image per frame, this is what my
tool does currently.
Today, I have not seen any public support by any tool for planar
4:2:0/4:1:0/4:2:2 TIFF compressed formats, maybe i am wrong, and you now
support it?
My current image i have generated here from TIFFInfo:
TIFF Directory at offset 0x112cec (1125612)
Image Width: 1392 Image Length: 968
Resolution: 73, 73 pixels/inch
Bits/Sample: 8
Compression Scheme: LZW
Photometric Interpretation: YCbCr
YCbCr Subsampling: 2, 2
Samples/Pixel: 3
Rows/Strip: 968
Planar Configuration: separate image planes
DateTime: 2022:05:04 00:11:44
YCbCrCoefficients: 0.299000,0.587000,0.114000
Reference Black/White:
0: 0 255
1: 128 255
2: 128 255
Predictor: horizontal differencing 2 (0x2)
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