Fixes for the chorus.

dev
Holger Wirtz 6 years ago
parent d5430fe5a4
commit 91df5f84a8
  1. 4
      config.h
  2. 40
      effect_modulated_delay.cpp
  3. 6
      effect_modulated_delay.h
  4. 209
      old/interpolation.cpp
  5. 79
      old/interpolation.h
  6. 64
      spline.cpp

@ -61,9 +61,9 @@
#define REDUCE_LOUDNESS 0 #define REDUCE_LOUDNESS 0
#define USE_XFADE_DATA 1 #define USE_XFADE_DATA 1
// CHORUS parameters // CHORUS parameters
#define INTERPOLATION_WINDOW_SIZE 7 // use only odd numbers!!! #define INTERPOLATION_WINDOW_SIZE 21 // use only odd numbers!!!
#define INTERPOLATE_MODE 11 #define INTERPOLATE_MODE 11
#define CHORUS_WAVEFORM WAVEFORM_TRIANGLE // WAVEFORM_SINE WAVEFORM_TRIANGLE WAVEFORM_SAWTOOTH WAVEFORM_SAWTOOTH_REVERSE #define CHORUS_WAVEFORM WAVEFORM_SINE // WAVEFORM_SINE WAVEFORM_TRIANGLE WAVEFORM_SAWTOOTH WAVEFORM_SAWTOOTH_REVERSE
#define CHORUS_DELAY_LENGTH_SAMPLES (15*AUDIO_BLOCK_SAMPLES) // one AUDIO_BLOCK_SAMPLES = 2.902ms; you need doubled length, e.g. delay point is 20ms, so you need up to 40ms delay! #define CHORUS_DELAY_LENGTH_SAMPLES (15*AUDIO_BLOCK_SAMPLES) // one AUDIO_BLOCK_SAMPLES = 2.902ms; you need doubled length, e.g. delay point is 20ms, so you need up to 40ms delay!
//************************************************************************************************* //*************************************************************************************************

@ -26,7 +26,6 @@
#include "limits.h" #include "limits.h"
#include "effect_modulated_delay.h" #include "effect_modulated_delay.h"
#include "spline.h" #include "spline.h"
#include "config.h"
/******************************************************************/ /******************************************************************/
@ -58,8 +57,6 @@ boolean AudioEffectModulatedDelay::begin(short *delayline, int d_length)
_delayline = delayline; _delayline = delayline;
_delay_length = _max_delay_length = d_length; _delay_length = _max_delay_length = d_length;
memset(_delayline, 0, sizeof(int16_t)*_delay_length);
return (true); return (true);
} }
@ -97,37 +94,46 @@ void AudioEffectModulatedDelay::update(void)
_circ_idx = 0; _circ_idx = 0;
_delayline[_circ_idx] = *bp; _delayline[_circ_idx] = *bp;
// calculate modulation index // Calculate modulation index as a float, for interpolation later.
mod_idx = float(*mp) / SHRT_MAX * float(_delay_length / 2); // calculate an index with modulation as a float(!!!) // The index is located around the half of the delay length multiplied by the current amount of the modulator
mod_idx = float(*mp) / SHRT_MAX * float(_delay_length >> 1);
#ifdef INTERPOLATE_MODE #ifdef INTERPOLATE_MODE
// get x/y values around mod_idx // Generate a an array with the size of INTERPOLATION_WINDOW_SIZE of x/y values around mod_idx for interpolation
uint8_t c = 0; uint8_t c = 0;
int16_t c_mod_idx = int(mod_idx + 0.5) + _circ_idx; int16_t c_mod_idx = _circ_idx - int(mod_idx + 0.5); // This is the pointer to the value in the circular buffer at the current modulation index
for (j = INTERPOLATION_WINDOW_SIZE / -2; j <= INTERPOLATION_WINDOW_SIZE / 2; j++) for (j = INTERPOLATION_WINDOW_SIZE / -2; j <= INTERPOLATION_WINDOW_SIZE / 2; j++)
{ {
int16_t jc_mod_idx = (c_mod_idx + j) % (_delay_length - 1); int16_t jc_mod_idx = (c_mod_idx + j) % _delay_length; // The modulation index pointer plus the value of the current window pointer
if (jc_mod_idx < 0) if (jc_mod_idx < 0)
y[c] = float(_delayline[_delay_length - 1 + jc_mod_idx]); y[c] = float(_delayline[_delay_length + jc_mod_idx]);
else else
y[c] = float(_delayline[jc_mod_idx]); y[c] = float(_delayline[jc_mod_idx]);
x[c] = float(c); x[c] = float(j);
c++; // because 42 is the answer! ;-) c++; // because 42 is the answer! ;-)
} }
*bp = int(s.value(modff(mod_idx, NULL)) + 0.5);
*bp = int(s.value(mod_idx - int(mod_idx + 0.5)) + 0.5);
#else #else
// No interpolation - should sound really bad... // No interpolation - should sound really bad...
int16_t c_mod_idx = (int(mod_idx + 0.5) + _circ_idx) % (_delay_length - 1); int16_t c_mod_idx = (_circ_idx - int(mod_idx + 0.5)) % _delay_length;
if (c_mod_idx < 0) if (c_mod_idx < 0)
*bp = _delayline[_delay_length - 1 + c_mod_idx]; *bp = _delayline[_delay_length + c_mod_idx];
else else
*bp = _delayline[c_mod_idx]; *bp = _delayline[c_mod_idx];
/* Serial.print("mod_idx=");
Serial.print(mod_idx, 3);
Serial.print(" c_mod_idx=");
Serial.print(c_mod_idx, DEC);
Serial.print(" MODULATION=");
Serial.print(*mp, DEC);
Serial.print(" DATA=");
Serial.print(*bp, DEC);
Serial.println();*/
#endif #endif
bp++; bp++; // next audio data
mp++; mp++; // next modulation data
_circ_idx++; _circ_idx++; // next circular buffer index
} }
} }

@ -26,7 +26,6 @@
#include "Arduino.h" #include "Arduino.h"
#include "AudioStream.h" #include "AudioStream.h"
#include "config.h"
/*************************************************************************/ /*************************************************************************/
@ -35,6 +34,9 @@
// 140219 - correct storage class (not static) // 140219 - correct storage class (not static)
// 190527 - added modulation input handling (by Holger Wirtz) // 190527 - added modulation input handling (by Holger Wirtz)
#define MODF(n,i,f) ((i) = (int)(n), (f) = (n) - (double)(i))
class AudioEffectModulatedDelay : class AudioEffectModulatedDelay :
public AudioStream public AudioStream
{ {
@ -50,7 +52,7 @@ class AudioEffectModulatedDelay :
private: private:
audio_block_t *inputQueueArray[2]; audio_block_t *inputQueueArray[2];
int16_t *_delayline; int16_t *_delayline;
int16_t _circ_idx; uint16_t _circ_idx;
uint16_t _max_delay_length; uint16_t _max_delay_length;
uint16_t _delay_length; uint16_t _delay_length;
}; };

@ -1,209 +0,0 @@
/*
* interpolation.h
*
* interpolation - An interpolation library for Arduino.
* Author: Jose Gama 2015
*
* This library is free software; you can redistribute it
* and/or modify it under the terms of the GNU Lesser
* General Public License as published by the Free Software
* Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser
* General Public License along with this library; if not,
* write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
/*
* From: https://github.com/tuxcell/interpolationArduino
* replaced all doubles by float (wirtz@parasitstudio.de)
*/
#include "interpolation.h"
interpolation::interpolation(void) {
_valInterp = 0;
_lenXY = 0;
}
interpolation::interpolation( float x[], float y[], int lenXY){
_x = x;_y = y;_lenXY = lenXY;
_valInterp = 0;
}
interpolation::interpolation( float x[], float y[], int lenXY, float valInterp){
_x = x;_y = y;_lenXY = lenXY;
_valInterp = valInterp;
}
void interpolation::valueI( float valInterp ) {
_valInterp = valInterp;
}
void interpolation::valuelenXY( int lenXY ) {
_lenXY = lenXY;
}
void interpolation::valueX( float x[]) {
_x = x;
}
void interpolation::valueY( float y[]) {
_y = y;
}
void interpolation::valueXM( float XM[]) {
_XM = XM;
}
void interpolation::valueZ( float Z[]) {
_Z = Z;
}
float interpolation::LinearInterpolate() {return(LinearInterp( _x, _y, _lenXY, _valInterp));}
float interpolation::CosineInterpolate() {return(CosineInterp( _x, _y, _lenXY, _valInterp));}
float interpolation::CubicInterpolate() {return(CubicInterp( _x, _y, _lenXY, _valInterp));}
float interpolation::LagrangeInterpolate() {return(LagrangeInterp( _x, _y, _lenXY, _valInterp));}
float interpolation::QuadraticInterpolate() {return(QuadraticInterp( _x, _y, _lenXY, _valInterp));}
float interpolation::AkimaInterpolate() {return(AkimaInterp( _x, _y, _XM, _Z, _lenXY, _valInterp));}
float interpolation::LinearInterp( float* x, float* y, int n, float p )
{
//http://paulbourke.net/miscellaneous/interpolation/
int i;
float mu;
for( i = 0; i < n-1; i++ )
{
if (( x[i] <= p && x[i+1] >= p )||( x[i] >= p && x[i+1] <= p ))
{
mu=(p - x[i])/(x[i] - x[i+1]);
if (mu<0) mu=-mu;
return(y[i]*(1-mu)+y[i+1]*mu);
}
}
return 0; // Not in Range
}
float interpolation::CosineInterp (float* x, float* y, int n, float p )
{
int i;
float mu, mu2;
for( i = 0; i < n-1; i++ )
{
if (( x[i] <= p && x[i+1] >= p )||( x[i] >= p && x[i+1] <= p ))
{
mu=(p - x[i])/(x[i] - x[i+1]);
if (mu<0) mu=-mu;
mu2 = (1.0-cos(3.1415926535897*mu))/2.0;
return(y[i]*(1.0-mu2)+y[i+1]*mu2);
}
}
return 0; // Not in Range
}
float interpolation::CubicInterp(float* x, float* y, int n, float p )
{
int i;
float a0,a1,a2,a3,mu, mu2;
for( i = 0; i < n-1; i++ )
{
if (( x[i] <= p && x[i+1] >= p )||( x[i] >= p && x[i+1] <= p ))
{
mu=(p - x[i])/(x[i] - x[i+1]);
if (mu<0) mu=-mu;
mu2 = mu*mu;
a0 = y[i+2] - y[i+1] - y[i-1] + y[i];
a1 = y[i-1] - y[i] - a0;
a2 = y[i+1] - y[i-1];
a3 = y[i];
return(a0*mu*mu2+a1*mu2+a2*mu+a3);
}
}
return 0; // Not in Range
}
float interpolation::LagrangeInterp( float* x, float* y, int n, float p )
{
//http://www.dailyfreecode.com/code/lagranges-interpolation-method-finding-2376.aspx
int i, j, k;
float t, r=0;
for(i=0;i<n;i++)
{
t = 1;
k = i;
for(j=0;j<n;j++)
{
if(k==j)
{
continue;
}
else
{
t = t * ((p-x[j])/(x[k]-x[j]));
}
}
r+=y[i]*t;
}
return r; // Not in Range
}
float interpolation::QuadraticInterp(float* x, float* y, int n, float p )
{
//view-source:http://www.johndcook.com/quadratic_interpolator.html
int i;
float xi2, k;
for( i = 0; i < n-1; i++ )
{
if (( x[i] <= p && x[i+1] >= p )||( x[i] >= p && x[i+1] <= p ))
{
if (i<(n-3)) xi2=x[i+2]; else xi2=0;
k = y[i]*(p - x[i+1])*(p - xi2)/((x[i] - x[i+1])*(x[i] - xi2));
k += y[i+1]*(p - x[i])*(p - xi2)/((x[i+1] - x[i])*(x[i+1] - xi2));
k += y[i+2]*(p - x[i])*(p - x[i+1])/((xi2 - x[i])*(xi2 - x[i+1]));
return(k);
}
}
return 0; // Not in Range
}
float interpolation::AkimaInterp( float* x, float* y, float* XM, float* Z, int n, float p ) {
//http://jean-pierre.moreau.pagesperso-orange.fr/Cplus/akima_cpp.txt
int i;
float a,b,r;
//special case p=0
if (p==0.0) {
return(0);
}
//Check to see if interpolation point is correct
if (p<x[1] || p>=x[n-3]) {
return(-330);
}
x[0]=2.0*x[1]-x[2];
//Calculate Akima coefficients, a and b
for (i=1; i<n; i++)
//Shift i to i+2
XM[i+2]=(y[i+1]-y[i])/(x[i+1]-x[i]);
XM[n+2]=2.0*XM[n+1]-XM[n];
XM[n+3]=2.0*XM[n+2]-XM[n+1];
XM[2]=2.0*XM[3]-XM[4];
XM[1]=2.0*XM[2]-XM[3];
for (i=1; i<n+1; i++) {
a=fabs(XM[i+3]-XM[i+2]);
b=fabs(XM[i+1]-XM[i]);
if (a+b==0) Z[i]=(a*XM[i+1]+b*XM[i+2])/(a+b); else Z[i]=(XM[i+2]+XM[i+1])/2.0;
}
//Find relevant table interval
i=0;
while (p>x[i]) i++;
i--;
//Begin interpolation
b=x[i+1]-x[i];
a=p-x[i];
r=y[i]+Z[i]*a+(3.0*XM[i+2]-2.0*Z[i]-Z[i+1])*a*a/b;
r=r+(Z[i]+Z[i+1]-2.0*XM[i+2])*a*a*a/(b*b);
return(r);
}

@ -1,79 +0,0 @@
/*
* interpolation.h
*
* interpolation - An interpolation library for Arduino.
* Author: Jose Gama 2015
*
* This library is free software; you can redistribute it
* and/or modify it under the terms of the GNU Lesser
* General Public License as published by the Free Software
* Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser
* General Public License along with this library; if not,
* write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
/*
* From: https://github.com/tuxcell/interpolationArduino
* replaced all doubles by float (wirtz@parasitstudio.de)
*/
#ifndef interpolation_h
#define interpolation_h
#if defined(ARDUINO) && ARDUINO >= 100
#include <Arduino.h>
#else
#include <WProgram.h>
#endif
class interpolation
{
public:
// constructor
interpolation( void );
interpolation( float x[], float y[], int lenXY);
interpolation( float x[], float y[], int lenXY, float valInterp);
void valueI( float valInterp );
void valuelenXY( int lenXY );
void valueX( float x[]);
void valueY( float y[]);
void valueXM( float XM[]);
void valueZ( float Z[]);
float LinearInterpolate();
float CosineInterpolate();
float CubicInterpolate();
float LagrangeInterpolate();
float QuadraticInterpolate();
float AkimaInterpolate();
private:
float* _x;
float* _y;
float* _XM;
float* _Z;
int _lenXY;
float _valInterp;
float LinearInterp( float x[], float y[], int n, float p );
float CosineInterp( float x[], float y[], int n, float p );
float CubicInterp( float x[], float y[], int n, float p );
float LagrangeInterp( float x[], float y[], int n, float p );
float QuadraticInterp( float x[], float y[], int n, float p );
float AkimaInterp( float x[], float y[], float XM[], float Z[], int n, float p );
};
#endif

@ -8,14 +8,14 @@ Spline::Spline(void) {
Spline::Spline( float x[], float y[], int numPoints, int degree ) Spline::Spline( float x[], float y[], int numPoints, int degree )
{ {
setPoints(x,y,numPoints); setPoints(x, y, numPoints);
setDegree(degree); setDegree(degree);
_prev_point = 0; _prev_point = 0;
} }
Spline::Spline( float x[], float y[], float m[], int numPoints ) Spline::Spline( float x[], float y[], float m[], int numPoints )
{ {
setPoints(x,y,m,numPoints); setPoints(x, y, m, numPoints);
setDegree(Hermite); setDegree(Hermite);
_prev_point = 0; _prev_point = 0;
} }
@ -33,78 +33,88 @@ void Spline::setPoints( float x[], float y[], float m[], int numPoints ) {
_length = numPoints; _length = numPoints;
} }
void Spline::setDegree( int degree ){ void Spline::setDegree( int degree ) {
_degree = degree; _degree = degree;
} }
float Spline::value( float x ) float Spline::value( float x )
{ {
if( _x[0] > x ) { if ( _x[0] > x ) {
return _y[0]; return _y[0];
} }
else if ( _x[_length-1] < x ) { else if ( _x[_length - 1] < x ) {
return _y[_length-1]; return _y[_length - 1];
} }
else { else {
for(int i = 0; i < _length; i++ ) for (int i = 0; i < _length; i++ )
{ {
int index = ( i + _prev_point ) % _length; int index = ( i + _prev_point ) % _length;
if( _x[index] == x ) { if ( _x[index] == x ) {
_prev_point = index; _prev_point = index;
return _y[index]; return _y[index];
} else if( (_x[index] < x) && (x < _x[index+1]) ) { } else if ( (_x[index] < x) && (x < _x[index + 1]) ) {
_prev_point = index; _prev_point = index;
return calc( x, index ); return calc( x, index );
} }
} }
} }
return (0.0);
} }
float Spline::calc( float x, int i ) float Spline::calc( float x, int i )
{ {
switch( _degree ) { switch ( _degree ) {
case 0: case 0:
return _y[i]; return _y[i];
case 1: case 1:
if( _x[i] == _x[i+1] ) { if ( _x[i] == _x[i + 1] ) {
// Avoids division by 0 // Avoids division by 0
return _y[i]; return _y[i];
} else { } else {
return _y[i] + (_y[i+1] - _y[i]) * ( x - _x[i]) / ( _x[i+1] - _x[i] ); return _y[i] + (_y[i + 1] - _y[i]) * ( x - _x[i]) / ( _x[i + 1] - _x[i] );
} }
case Hermite: case Hermite:
return hermite( ((x-_x[i]) / (_x[i+1]-_x[i])), _y[i], _y[i+1], _m[i], _m[i+1], _x[i], _x[i+1] ); return hermite( ((x - _x[i]) / (_x[i + 1] - _x[i])), _y[i], _y[i + 1], _m[i], _m[i + 1], _x[i], _x[i + 1] );
case Catmull: case Catmull:
if( i == 0 ) { if ( i == 0 ) {
// x prior to spline start - first point used to determine tangent // x prior to spline start - first point used to determine tangent
return _y[1]; return _y[1];
} else if( i == _length-2 ) { } else if ( i == _length - 2 ) {
// x after spline end - last point used to determine tangent // x after spline end - last point used to determine tangent
return _y[_length-2]; return _y[_length - 2];
} else { } else {
float t = (x-_x[i]) / (_x[i+1]-_x[i]); float t = (x - _x[i]) / (_x[i + 1] - _x[i]);
float m0 = (i==0 ? 0 : catmull_tangent(i) ); float m0 = (i == 0 ? 0 : catmull_tangent(i) );
float m1 = (i==_length-1 ? 0 : catmull_tangent(i+1) ); float m1 = (i == _length - 1 ? 0 : catmull_tangent(i + 1) );
return hermite( t, _y[i], _y[i+1], m0, m1, _x[i], _x[i+1]); return hermite( t, _y[i], _y[i + 1], m0, m1, _x[i], _x[i + 1]);
} }
} }
return (0.0);
} }
float Spline::hermite( float t, float p0, float p1, float m0, float m1, float x0, float x1 ) { float Spline::hermite( float t, float p0, float p1, float m0, float m1, float x0, float x1 ) {
return (hermite_00(t)*p0) + (hermite_10(t)*(x1-x0)*m0) + (hermite_01(t)*p1) + (hermite_11(t)*(x1-x0)*m1); return (hermite_00(t) * p0) + (hermite_10(t) * (x1 - x0) * m0) + (hermite_01(t) * p1) + (hermite_11(t) * (x1 - x0) * m1);
}
float Spline::hermite_00( float t ) {
return (2 * pow(t, 3)) - (3 * pow(t, 2)) + 1;
}
float Spline::hermite_10( float t ) {
return pow(t, 3) - (2 * pow(t, 2)) + t;
}
float Spline::hermite_01( float t ) {
return (3 * pow(t, 2)) - (2 * pow(t, 3));
}
float Spline::hermite_11( float t ) {
return pow(t, 3) - pow(t, 2);
} }
float Spline::hermite_00( float t ) { return (2*pow(t,3)) - (3*pow(t,2)) + 1;}
float Spline::hermite_10( float t ) { return pow(t,3) - (2*pow(t,2)) + t; }
float Spline::hermite_01( float t ) { return (3*pow(t,2)) - (2*pow(t,3)); }
float Spline::hermite_11( float t ) { return pow(t,3) - pow(t,2); }
float Spline::catmull_tangent( int i ) float Spline::catmull_tangent( int i )
{ {
if( _x[i+1] == _x[i-1] ) { if ( _x[i + 1] == _x[i - 1] ) {
// Avoids division by 0 // Avoids division by 0
return 0; return 0;
} else { } else {
return (_y[i+1] - _y[i-1]) / (_x[i+1] - _x[i-1]); return (_y[i + 1] - _y[i - 1]) / (_x[i + 1] - _x[i - 1]);
} }
} }

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