- added compressor

git-svn-id: http://moon:8086/svn/matlab/trunk@127 801c6759-fa7c-4059-a304-17956f83a07c

compressor/Makefile

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+all:
+	mkoctfile -mex level_detect.c

compressor/cmp_eval.m

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+## Copyright (C) 2020 Jens
+## 
+## This program is free software: you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see
+## <https://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} {@var{retval} =} eq_eval (@var{input1}, @var{input2})
+##
+## @seealso{}
+##
+## Exapmple: cmp_eval("snip.wav", 0.25, -40, 18);
+## @end deftypefn
+
+## Author: Jens <jens@orion>
+## Created: 2020-06-22
+
+function cmp_eval (filename_in, R, lev_knee_dB, gain_makeup_dB)
+
+fs = 48000
+[x, fs] = audioread(filename_in);
+N = size(x)(1)
+num_channels = size(x)(2)
+filename_out = to_filename_out(filename_in, "out");
+
+time_look_ahead = 0.01;
+time_attack = 0.01;
+time_release = 1.0;
+
+n_look_ahead = round(time_look_ahead*fs);
+h_dly = [zeros(1, n_look_ahead-1) 1];
+
+x_dly = filter(h_dly, 1, x);
+
+alpha_a = 5/(time_attack*fs);
+alpha_r = 5/(time_release*fs);
+
+lev = level_detect(x, alpha_a, alpha_r);
+lev_dB = max(-120, 20*log10(lev));
+
+k_makeup_gain = 10^(gain_makeup_dB/20);
+gain1 = min(8, (1/8)./(lev+0.1));
+[lev_out_dB, gain2_dB] = cmp_gain(R, lev_knee_dB, lev_dB);
+gain2 = 10.^(gain2_dB/20);
+y1 = gain1.*x_dly * 2;
+y2 = gain2.*x_dly * k_makeup_gain;
+audiowrite(to_filename_out(filename_in, "gain1"), gain1, fs)
+audiowrite(to_filename_out(filename_in, "gain2"), gain2, fs)
+audiowrite(to_filename_out(filename_in, "out1"), y1, fs)
+audiowrite(to_filename_out(filename_in, "out2"), y2, fs)
+audiowrite(to_filename_out(filename_in, "lev"), lev, fs)
+
+gain_out = [];
+gain_in = [];
+for g=0:0.1:1,
+	gain_out = [gain_out cmp_gain(R, g, 0.01)];
+	gain_in = [gain_in g];
+endfor
+plot(gain_in, gain_out); grid();
+
+endfunction
+

compressor/cmp_gain.m

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+function [lev_out_dB, gain_out_dB] = cmp_gain(R, lev_knee_dB, lev_in_dB)
+	k = lev_in_dB > lev_knee_dB;
+	lev_out_dB = (1-k).*lev_in_dB + k.*(lev_knee_dB + R*(lev_in_dB - lev_knee_dB));
+	gain_out_dB = - (lev_in_dB - lev_out_dB);
+endfunction

compressor/cmp_gain_eval.m

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+## Copyright (C) 2020 Jens
+## 
+## This program is free software: you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see
+## <https://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} {@var{retval} =} eq_eval (@var{input1}, @var{input2})
+##
+## @seealso{}
+## @end deftypefn
+
+## Author: Jens <jens@orion>
+## Created: 2020-06-22
+
+function cmp_gain_eval (R)
+epsilon = 0.01;
+dl = 10;
+gain_out = [];
+lev_out = [];
+lev_in = [];
+for li=-120:dl:0,
+	[lo, go] = cmp_gain(R, -20, li);
+	lev_out = [lev_out lo];
+	lev_in = [lev_in li];
+	gain_out = [gain_out go];
+endfor
+close;
+plot(lev_in, lev_out, lev_in, gain_out); grid();
+
+endfunction
+

compressor/level_detect.c

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+#include <mex.h>
+#include <math.h>
+void mexFunction (int nlhs, mxArray *plhs[],
+             int nrhs, const mxArray *prhs[])
+{
+	const char *funcName = mexFunctionName ();
+	mexPrintf ("You called function: %s\n", funcName);
+	mexPrintf ("I have %d inputs and %d outputs\n", nrhs, nlhs);
+
+	if (nrhs < 3)
+		mexErrMsgTxt ("Too few arguments");
+
+	const mxArray *array_x = prhs[0];
+	const mxArray *scalar_alpha_attack = prhs[1];
+	const mxArray *scalar_alpha_release = prhs[2];
+
+	
+	plhs[0] = mxCreateNumericArray (mxGetNumberOfDimensions (array_x),
+								  mxGetDimensions (array_x),
+								  mxGetClassID (array_x),
+								  mxIsComplex (array_x));
+
+	mwIndex channelsDim = 1;
+	double alpha_a = *mxGetPr(scalar_alpha_attack);
+	double alpha_r = *mxGetPr(scalar_alpha_release);
+
+	double *vri = mxGetPr (array_x);
+	double *vro = mxGetPr (plhs[0]);
+	
+	mwSize M = mxGetM (array_x);
+	mwSize N = mxGetN (array_x);
+	if (channelsDim == 1)
+	{
+		M = mxGetN (array_x);
+		N = mxGetM (array_x);
+	}
+
+	mexPrintf ("Number of channels = %u\n", M);
+	mexPrintf ("Number of samples per channel = %u\n", N);
+	mexPrintf ("alpha_a = %f\n", alpha_a);
+	mexPrintf ("alpha_r = %f\n", alpha_r);
+	
+	double level[M];
+	for (mwIndex m=0; m < M; m++)
+	{
+		level[m] = 0;
+	}	
+	
+	for (mwIndex n=0; n < N; n++)
+	{
+		for (mwIndex m=0; m < M; m++)
+		{
+			double x = vri[n*M + m];
+			double xmag = fabs(x);
+				
+			if (xmag > level[m])
+			{
+				level[m] = (1.0-alpha_a)*level[m] + alpha_a*xmag;
+			}
+			else
+			{
+				level[m] = (1.0-alpha_r)*level[m];
+			}
+			vro[n*M + m] = level[m];
+		}	
+	}
+}
+
+
+