AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2022.05.11 16:37 "[Tiff] YCbCr Planar subsampled format support", by Carl Eric Codere
2022.05.12 13:45 "Re: [Tiff] YCbCr Planar subsampled format support", by Bob Friesenhahn
2022.05.14 07:45 "Re: [Tiff] YCbCr Planar subsampled format support", by Carl Eric Codere

2022.05.12 13:45 "Re: [Tiff] YCbCr Planar subsampled format support", by Bob Friesenhahn

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.

I did not see any response to your question.

There is a sample/test program provided with libtiff sources called rgb2ycbcr.c to encode YCbCr TIFF with subsampling, but this does not appear to support creating planar/separated TIFF files.

The lack of a utility to encode/decode YCbCr planar images does not mean that libtiff does not 'support' it since libtiff is primarily a library and applications using libtiff are able to use the tiff library to do things that the provided utilities do not support. The application using libtiff would need to do YCbCr down/up sampling outside of libtiff but nothing should prevent storing the result.

I would immediately agree that planar TIFF may be easier for some applications to deal with (depending on the sampling involved), but subsampled encoded YCbCr may be easier for other applications to deal with.

Simple compression is more likely to work well by default with planar representation.

Bob

Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
Public Key, http://www.simplesystems.org/users/bfriesen/public-key.txt