Graillon 1.0, VST effect fully made with D

[Ola Fosheim Grøstad via Digitalmars-d-announce]

On Sunday, 29 November 2015 at 15:13:41 UTC, Guillaume Piolat 
wrote:
> The hard thing about live pitch-tracking is getting the minimal 
> latency keeping reliability. It's not that simple. You also 
> want "voicedness", which is more challenging than pitch.

I think they developed it for a specific work, but IIRC it was 
challenging to get it accurate.

I don't now much about current pitch trackers, but I think you 
can do a high quality one for voice using filterbanks. Some 
people do resynthesis that way (and well, that is just an 
alternative to FFT after all). That's pretty much how cochlea 
works, I think, by having overlapping frequency bands. But it 
probably is hard to get right. I assume you can make a better 
pitch tracker that is specialized for voice by thinking about FoF 
synthesis, the sound of the voice is really a sequence of bursts 
of roughly the same shape (like granular synthesis in a way) and 
you should be able to figure out some statistical relationship 
between formants and how they change with pitch. I'm not saying 
it is easy. Probably a lot published on this though.

I don't know what "voicedness" is? You mean things like vibrato?

> I've not tried the multiple FFT, I was worried pitch would lag 
> oddly when changing FFT size. Perhaps it could work.

I think it should work in theory, but you'll probably get some of 
complications due to the distortions that comes with the 
windowing function etc? And making a real time phase vocoder is 
more work than it looks like on paper... Obviously doable, but 
there are some "missing bits" in the theoretical descriptions. I 
guess that's why IRCAM can sell licenses to superVP. :)

>> Or maybe one can use wavelets, but I don't know much about 
>> wavelet transforms (they don't map to cosine, so imagine it 
>> will be much harder to do well).
>
> I have trouble to imagine the reconstruction so don't use them 
> (well, I did once, but didn't _get_ it).

Yeah, I don't know. Still, in the past few years it has been 
popular with distorted and glitchy sounds, so maybe one could do 
some cool distorted effects with it.