2021.04.18 15:57 "[Tiff] Scalar & SIMD optimization", by Larry Bank

Hi all. I'm new to this group and would like some feedback on a few ideas. Many years ago I wrote optimized codecs for all standard image compression types and recently decided to start sharing the code to the open source community. My first releases were for the embedded/Arduino community because I thought it would have the most impact:


Then I saw the need to optimize open source libraries with a wider reach (e.g. giflib, libTIFF, libPNG). I created a much faster version of giflib:


After poking around libTIFF, it surprised me that no one had bothered to optimize certain parts with SIMD. SIMD optimization is even more important on the new Apple M1; the speed difference is tremendous.

I don't personally use libTIFF, libPNG, libjpeg or giflib because I wrote my own codecs. This is the basic problem with randomly optimizing other people's code. I don't have a personal stake in this work because I don't use it. This also complicates testing since I don't have any projects which depend on the code.

From my testing, my work can bring the following benefits to libTIFF:

I have a full time job and a family, so free time is scarce. I'll help with optimization if there is a clear benefit to the community.

Finally... what I'm asking of this group is the following:

Thanks for listening,

Larry Bank