The Adaptive Multi-Rate (AMR, AMR-NB or GSM-AMR) audio codec is an audio compression format optimized for speech coding.AMR speech codec consists of a multi-rate narrowband speech codec that encodes narrowband (200–3400 Hz) signals at variable bit rates ranging from 4.75 to 12.2 kbit/s with toll quality speech starting at 7.4 kbit/s.However, if you use the ProperTree OpenCore ist editor, quite a bit of the work is automated.
This is probably the most tedious part: setting up OpenCore in the EFI folder, and creating a ist file.
