Parallelized PNG encoder using OpenMP and libpng

This is a parallelized PNG encoder written in C++ using OpenMP and libpng.

This application has to be seen as a proof of concept as it was developed for a seminar paper during my study.

Feel free to use, enhance or whatever.

Requirements

• libboost-program-options-dev
• libmagick++-dev
• libpng-dev
• zlib-dev

Compilation

Run "make all"

Execution

./pngencoder -i INPUT_FILE.ext -o OUTPUT_FILE.png --num_threads=NUMBER

Known issues

• Returns with error "pngencoder: magick/cache.c:2053: GetAuthenticPixelsCache: Assertion 'id < (long) cache_info->number_threads' failed." if the number of threads is higher than the available amount of CPUs. Seems to be a bug in ImageMagick.
• It does not use any filtering for the rows so the deflate compression ratio is pretty bad.