I have been working on an apparently very 'kind' compressor/agc program (mostly developed on Linux, but have been building parallel Windows versions.) It isn't just a straightforward AGC, but has careful algorithms and artifact avoidance. It has both single band and multi-band modes (running simultaneously due to an artifact of current CPU design/parallel algorithms.) It works well anywhere from 1.2:1 to inf:1 compression, but doesn't try to mindlessly achieve the numeric goal of always reaching the target level. It also has a well designed peak limiter, and can easily keep the signal below maximum without overshoot. (It does have a minor problem -- yet to be resolved -- that a subsequent brickwall filter will naturally cause ringing.) I am planning on putting together a nonlinear filter for high freqs on the output to prefilter the signal so that subsequent brickwalls don't overshoot.
I am willing to freely distribute binaries at this point (it doesn't have any source encumbered components -- by far most of it is my own carefully crafted C++.) After I get some good feedback, I am planning on free source distribution (I have some interesting code concepts that I will probably need to defend, and simply want proof of performance before laying it all out in public.) I have done lots of free software in the past (wrote significant amount of freely available OS code in the early internet days), so I am not fly-by-night, but also don't have any good contacts for providing/distributing this technology. I can have a 'most recent' version built within hours -- I have a days-old version running right now. The binary distribution is 6MB (an approx 1.5MB binary, and some Cygwin dlls), and/or I can provide a Linux-x86_64 version that has no compromised algorithms. It runs realtime on Silvermont or better. (I normally use a quad Haswell on workstation, but have a dual CPU silvermont laptop that I test on.) I can do a core2/Silvermont or an optimized AVX2(Haswell) build. I benefits from 2 or more threads (it is multi-threaded to maintain realtime performance.) Let me know if anyone is interested -- and I am willing to work with people who are really interested.