GT3b2 with HF Reduction, Proof of concept Options

[QuantumKnot]

I've included the HF boost reduction technique I used in QKTune beta 3.2 into the current GT3b2, as a proof of concept.

You can download the binary here:
http://www.hydrogenaudio.org/forums/index....ndpost&p=188227

The nice pre-echo handling of the original GT3b2 may be slightly worse. Start at -q 5 and compare this with the original GT3b1/GT3b2 and see whether the HF boost is there or not.

[QuantumKnot]

Many thanks to guruboolez for his listening tests. The term 'reduce' is definitely the appropriate one here since I'm not really fixing the source of the problem but rather, trying to compensate for it which means my settings may not be optimal and more tuning is needed. Also, I only focused on reducing one type of HF boost.

Unfortunately, I have no answer at this time for how to fix the coarse and grainy noise that appears in classical music. I suspect there is no easy way of compensating for it (in a consistent way) and one will have to look into the code deeply. But after the experimenting I've personally done, there are a few things I discovered:

1. Most of these problems seem to have little to do with stereo coupling. I've replaced point stereo with lossless coupling and stilll, I get the HF boost. Nothing seems to be wrong with lossless coupling either since I've checked the coupling and decoupling code and everything should decouple right. Hence I believe point stereo is magnifying the problem but is not the cause of it.

2. Since the HF boost is present in both point and lossless stereo, then the source of the problem either lies in the floor generation, the floor removal, or the residue quantisation. I'm leaning towards perhaps the third process as being the cause since it is entirely consistent with what other people on the vorbis-dev mailing list suspect....unusually low SNR in high frequencies causing a high increase in energy due to quantisation noise.