The IEM Plug-in Suite was created by staff and students student of the Institute of Electronic Music and Acoustics in Graz. It is free and open source. Downloads and documentation can be found here https://plugins.iem.at/.
The Plug-in Suite include several tools for encoding and decoding ambisonics signals as well as processing tools useful working with ambisonics or multichannel audio, including different encoders, EQ, compressor, ...
Mostly it used as VST-Plugins which were made with REAPER as DAW target which is most suitable for working with ambisonics because of its flexible channellayout but there also standalone applications available.
The plugins are using AmbiX (Ambisonic eXchange) as format this means: * channel order ACN: WYZX * normalization SN3D