2022.12.11 16:37 "Re: [Tiff] libtiff v4.5.0 release candidate available", by Bob Friesenhahn

"TIFFReadDirectory: Warning, Didn't read next directory due to IFD looping at offset 0xa7ff1e (11009822) to offset 0x8 (8)."

Error: "Cannot handle more than 65535 TIFF directories"

The test file at <https://github.com/cgohlke/imagecodecs/blob/master/tests/tiff/gray.movie.u2.tif> contains 65567 pages.

This test file reveals something else which is concerning. I ran a profiler on GraphicsMagick while it was reading this file and I see that 53% of the time is being spent in _TIFFCheckDirNumberAndOffset().

Most of the time is being spent in the code associated with "Check if offset is already in the list".

I assumed that most of the time would be spent in GraphicsMagick code.

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