The s3a decorrelation toolbox is an open-source set of tools for decorrelating audio. It includes the s3a decorrelator, an upmix algorithm written in python. The algorithm can also be used to upmix any audio source to any number of channels. The algorithm is blind and the resultant upmix remains mono compatible.
It was designed to maximise envelopment for diffuse sound objects such as ambience, applause and reverberation but can be used for any source material.