so you look up a-law and mu-law, and they are upselling them so freakin hard, with all the terminology and the sophistication of the study of the human hearing, and nature of audio signals, and speech in particular, and then follow up with formulas so backwards and mathy you have to wonder if logs are base 2 or base e... and of cource you have classic "you don't need to understand this stupid programmer, just use this lookup table" scaremongering

then you read up on the actual standard codec spec
https://en.wikipedia.org/wiki/G.711
and it turns out it's basically just

float compress(long long value)
{ return value; }

except smaller and simpler