PNG Encoding is slower than .Net Framework System.Windows.Media with the same compression level

[ratok-mk]

A performance comparison of 100 times encoding and decoding of 2560 x 1920 PNG 16bit greyscale image on Intel Core i7 8850H took:
System.Windows.Media: ~30 seconds
ImageSharp BestSpeed: ~34 seconds
ImageSharp DefaultCompression: ~60 seconds

Debugging showed that decoding was close together, but encoding took far more time for ImageSharp.

[JimBobSquarePants]

No. If it’s a problem for you. Look into it yourself.

[ratok-mk]

I will give it a try. All hints are welcome, where to look first.

[JimBobSquarePants]

We're using a custom DeflateStream implementation for Png encoding because the runtime DeflateStream implementation does not allow setting the compression range or properly and also failed to compress certain pixel layouts well.

Before doing any work I would create a proper benchmark (using BenchMarkDotNet) to ensure that you are comparing like-for-like compression. There's a lot more to encoding than simply comparing compression speed. If System.Windows.Media is anything like System.Drawing there's generally about 15% difference in file output size between ourselves an them.