TL;DR

LodePNG is not so fast. 😢

Introduction

PngBench calculates the decompression time of several PNG decoders by using Windows' native icons as test suite.

Currently, the following decoders are supported:

• GDI+
• Windows Imaging Component (WIC)
• libpng + zlib
• LodePNG & picoPNG
• uPNG
• stb_image

Usage

1. Build libpng and zlib.
2. Put libpng.lib and zlib.lib into libpng/ folder and zlib/ folder respectively.
3. Run nmake on the developer command prompt.
4. Run either pngbench_n or pngbench_c.

Example Result

Decoder	Speed (ms)
WIC	700
GDI+	945
libpng+zlib	1708
stb_image	2007
LodePNG+zlib	2292
uPNG	2598
LodePNG	3123
picoPNG	3758

Memo

• WIC has MMX, SSE2 and SSSE3 optimised code for filter and decompression.
• GDI+ just delegates WIC to decode images.
• libpng has SSE2 optimised code for filter.
• zlib has experimental MMX and/or hand-tuned assembly code for decompression.

Todo

• Verify decompressed images (maybe something's wrong with results)
• Add miniz support
• Apply some SIMD patch to zlib

License

Released under the WTFPL except third party libraries.