FFTReal v1.1
This is one of the best real FFT/iFFT transforms available in existence! I have gone through at least 10, and kept upgrading until I found this one, so I adapted it for SIMD capability, optimized it in C++ and neon asm a bit.
This is what I am using now in all of my audio projects instead of AVFFT, PFFFT, etc. It is by far the best sounding that I found that is also fast as lightning.
NEW v1.1: I optimized the algo a bit with neon inline asm but I am no wizard at neon, just trying to learn. If anyone wanting to optimize this further, I'd appreciate if you send me your optimizations, email below.