The Sonoris Dither is a professional, high quality audio plugin for mastering purposes.
With this plugin you can quantize audio to a lower bitdepth with dither and/or noiseshaping. The dither type is selectable between TPDF and High Pass (HP) TPDF. TPDF is short for Triangular Probability Densitity Function, a form of dither that eliminates non-linear distortion during re-quantization and has no signal modulation artifacts. The noiseshaping can be set to three flavors: Curve A, B and C or "Off". It is also possible to set noiseshaping without dither. The output bitdepth can be set to 16 and 20 bit or "Off" for no quantization.