Hi Julius, Thanks for the trick, it works pretty well: I can compile it using faust compiler and options -lang cpp -scal -ftz 0 with 300 samples. I will try for more with some more time. The web assembly seems not to like it actually.
I did not try yet to see if the detected pitch is accurate. But I think you got the idea. Thanks :) Nicolas > On 6 May 2020, at 19:21, Julius Smith <julius.sm...@gmail.com> wrote: > > Hi Nicolas, > > It looks like you are asking for unbounded correlation lags. Try limiting it > with something like i = min(1e8,+(1)) ~_ ; > > - Julius > > On Tue, May 5, 2020 at 11:56 PM Nicolas Gravillon <gravil...@gmail.com > <mailto:gravil...@gmail.com>> wrote: > Hi everyone, > > First of all, thank you all for your amazing achievement with Faust. I am > delighted to use it and amazed by all this work. Regarding my problem, I try > for some time now to implement a pitch tracker implementing autocorrelation, > for a more reliable metering than the zero crossing method. I ended with the > following version, strongly inspired from Tiziano Bole work : > > import("stdfaust.lib"); > > BufferLength=4; > > pitch(x) = ma.SR / max(M, 1) - ma.SR * (M == 0) > with { > AC(x, k) = sum(j, BufferLength, (x@(j))*(x@(j+k))) / (BufferLength) ; // > Correlating two signals, on the buffer length, ideally over 600 samples with > actual SR > i = +(1) ~_ ; > U = AC(x,i) > AC(x,0)/2; // Detection of a good correlation, > AC(x,0) being the highest possible value, so its half becomes the detection > threshold > V = AC(x,i) <= AC(x,i+1); > W = AC(x,i+1) > AC(x,i+2); > Y = U: *(V) : *(W); > > N = (+(1) : *(1 - Y)) ~ _; > M = (N' + 1) : ba.sAndH(Y); > }; > > process = pitch : hbargraph(“Frequency", 50, 2000); > > The problem seems to be located in the Autocorrelation function : AC(x, k) > = sum(j, BufferLength, (x@(j))*(x@(j+k))) / (BufferLength) since the error > says “can’t compute the min and max values of […] used in delay expression > […] (probably a recursive signal). > > Any chance to get it working? I do not see actually how to fix boundaries for > the delay lines, or get rid of the recursive guess from the compiler. > > Thanks for reading this, > > Nicolas > _______________________________________________ > Faudiostream-users mailing list > Faudiostream-users@lists.sourceforge.net > <mailto:Faudiostream-users@lists.sourceforge.net> > https://lists.sourceforge.net/lists/listinfo/faudiostream-users > <https://lists.sourceforge.net/lists/listinfo/faudiostream-users> > > > -- > "Anybody who knows all about nothing knows everything" -- Leonard Susskind
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