This code repository contains the original GSM-EFR reference code from ETSI
(taken from ts_146053v080000p0.zip), plus some small surgical patches (grafts
of code from AMR reference source) conditionalized with #ifdef EFR2_VARIANT.
In std directory we build the standard version of ETSI EFR encoder and decoder
(no hacks applied), and in efr2 directory we build our experimental hack
versions with -DEFR2_VARIANT.

Please read the accompanying Theory-and-mystery article for an explanation of
what the fuss is all about.