2010.11.16 20:09 "Re: [Tiff] unknown field with tag 317 (0x13d) encountered.", by E. Rosten
I'm trying to read a TIFF file, which seems to have the predictor set. I get the error message:
TIFFReadDirectory: Warning, std::istream: unknown field with tag 317 (0x13d) encountered.
and the TIFF appears to be quantized to a very small number of levels.
This is from my own software and I get very similar results from other software installed on the system. I have tried the latest version (3.9.4), with the following results from the configure script:
This file seems to use 16-bits per sample. Perhaps the "quantization" you are seeing is due to 16-bits being squashed down to 8-bits/sample as supported by common image display software. Sometimes 16-bit/sample images only use levels which don't map well to 8-bit. This is a common problem.
Ah! Thanks. I've found the bug. It appears that this TIFF doesn't have samplesperpixel set, and I wasn't defaulting it properly to 1. So, I was calling the cooked RGB interface because I didn't know how to cope with 0 samples per pixel.
I guess the unknown tag was a red herring.
Edward Rosten Machine Intelligence Laboratory
http://mi.eng.cam.ac.uk/~er258 Department of Engineering
+44 1223 7 65960 University of Cambridge