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Merge pull request #1291 from diizy/filters

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Even More Filters
This commit is contained in:
Vesa V
2014-11-13 20:45:56 +02:00
parent 16fb09fb94 4aaeb73f71
commit 14d4c37bab
3 changed files with 145 additions and 53 deletions
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189
include/basic_filters.h
View File

@@ -72,8 +72,11 @@ public:
Lowpass_SV,
Bandpass_SV,
Highpass_SV,
Notch_SV,
FastFormant,
Tripole,
NumFilters
} ;
};
static inline float minFreq()
{
@@ -147,6 +150,9 @@ public:
m_y1[_chnl] = m_y2[_chnl] = m_y3[_chnl] = m_y4[_chnl] =
m_oldx[_chnl] = m_oldy1[_chnl] =
m_oldy2[_chnl] = m_oldy3[_chnl] = 0.0f;
// tripole
m_last[_chnl] = 0.0f;
// reset in/out history for RC-filters
m_rclp0[_chnl] = m_rcbp0[_chnl] = m_rchp0[_chnl] = m_rclast0[_chnl] = 0.0f;
@@ -175,22 +181,22 @@ public:
// four cascaded onepole filters
// (bilinear transform)
m_y1[_chnl] = tLimit(
m_y1[_chnl] = qBound( -10.0f,
( x + m_oldx[_chnl] ) * m_p
- m_k * m_y1[_chnl],
-10.0f, 10.0f );
m_y2[_chnl] = tLimit(
10.0f );
m_y2[_chnl] = qBound( -10.0f,
( m_y1[_chnl] + m_oldy1[_chnl] ) * m_p
- m_k * m_y2[_chnl],
-10.0f, 10.0f );
m_y3[_chnl] = tLimit(
10.0f );
m_y3[_chnl] = qBound( -10.0f,
( m_y2[_chnl] + m_oldy2[_chnl] ) * m_p
- m_k * m_y3[_chnl],
-10.0f, 10.0f );
m_y4[_chnl] = tLimit(
10.0f );
m_y4[_chnl] = qBound( -10.0f,
( m_y3[_chnl] + m_oldy3[_chnl] ) * m_p
- m_k * m_y4[_chnl],
-10.0f, 10.0f );
10.0f );
m_oldx[_chnl] = x;
m_oldy1[_chnl] = m_y1[_chnl];
@@ -201,22 +207,61 @@ public:
break;
}
// 3x onepole filters with 4x oversampling and interpolation of oversampled signal:
// input signal is linear-interpolated after oversampling, output signal is averaged from oversampled outputs
case Tripole:
{
out = 0.0f;
float ip = 0.0f;
for( int i = 0; i < 4; ++i )
{
ip += 0.25f;
sample_t x = linearInterpolate( m_last[_chnl], _in0, ip ) - m_r * m_y3[_chnl];
m_y1[_chnl] = qBound( -10.0f,
( x + m_oldx[_chnl] ) * m_p
- m_k * m_y1[_chnl],
10.0f );
m_y2[_chnl] = qBound( -10.0f,
( m_y1[_chnl] + m_oldy1[_chnl] ) * m_p
- m_k * m_y2[_chnl],
10.0f );
m_y3[_chnl] = qBound( -10.0f,
( m_y2[_chnl] + m_oldy2[_chnl] ) * m_p
- m_k * m_y3[_chnl],
10.0f );
m_oldx[_chnl] = x;
m_oldy1[_chnl] = m_y1[_chnl];
m_oldy2[_chnl] = m_y2[_chnl];
out += ( m_y3[_chnl] - m_y3[_chnl] * m_y3[_chnl] * m_y3[_chnl] * ( 1.0f / 6.0f ) );
}
out *= 0.25f;
m_last[_chnl] = _in0;
break;
}
// 4-pole state-variant lowpass filter, adapted from Nekobee source code
// and extended to other SV filter types
// /* Hal Chamberlin's state variable filter */
case Lowpass_SV:
case Bandpass_SV:
{
m_sva[_chnl] += ( qAbs( _in0 ) - m_sva[_chnl] ) * m_svsr;
float highpass;
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl]; /* delay2/4 = lowpass output */
float highpass = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * highpass + m_delay1[_chnl]; /* delay1/3 = bandpass output */
for( int i = 0; i < 2; ++i ) // 2x oversample
{
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl]; /* delay2/4 = lowpass output */
highpass = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * highpass + m_delay1[_chnl]; /* delay1/3 = bandpass output */
m_delay4[_chnl] = m_delay4[_chnl] + m_svf2 * m_delay3[_chnl];
highpass = m_delay2[_chnl] - m_delay4[_chnl] - m_svq * m_delay3[_chnl];
m_delay3[_chnl] = m_svf2 * highpass + m_delay3[_chnl];
}
m_delay4[_chnl] = m_delay4[_chnl] + m_svf2 * m_delay3[_chnl];
highpass = m_delay2[_chnl] - m_delay4[_chnl] - m_svq * m_delay3[_chnl];
m_delay3[_chnl] = m_svf2 * highpass + m_delay3[_chnl];
/* mix filter output into output buffer */
out = m_type == Lowpass_SV
? atanf( 3.0f * m_delay4[_chnl] * m_sva[_chnl] )
@@ -227,14 +272,39 @@ public:
case Highpass_SV:
{
m_sva[_chnl] += ( qAbs( _in0 ) - m_sva[_chnl] ) * m_svsr;
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl];
float hp = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * hp + m_delay1[_chnl];
float hp;
for( int i = 0; i < 2; ++i ) // 2x oversample
{
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl];
hp = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * hp + m_delay1[_chnl];
}
out = atanf( 3.0f * hp * m_sva[_chnl] );
break;
}
case Notch_SV:
{
m_sva[_chnl] += ( qAbs( _in0 ) - m_sva[_chnl] ) * m_svsr;
float hp1, hp2;
for( int i = 0; i < 2; ++i ) // 2x oversample
{
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl]; /* delay2/4 = lowpass output */
hp1 = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * hp1 + m_delay1[_chnl]; /* delay1/3 = bandpass output */
m_delay4[_chnl] = m_delay4[_chnl] + m_svf2 * m_delay3[_chnl];
hp2 = m_delay2[_chnl] - m_delay4[_chnl] - m_svq * m_delay3[_chnl];
m_delay3[_chnl] = m_svf2 * hp2 + m_delay3[_chnl];
}
/* mix filter output into output buffer */
out = atanf( 1.5f * ( m_delay4[_chnl] + hp1 ) * m_sva[_chnl] );
break;
}
// 4-times oversampled simulation of an active RC-Bandpass,-Lowpass,-Highpass-
@@ -376,11 +446,13 @@ public:
}
case Formantfilter:
case FastFormant:
{
sample_t hp, bp, in;
out = 0;
for(int o=0; o<4; o++)
const int os = m_type == FastFormant ? 1 : 4; // no oversampling for fast formant
for( int o = 0; o < os; ++o )
{
// first formant
in = _in0 + m_vfbp[0][_chnl] * m_vfq;
@@ -466,7 +538,7 @@ public:
out += bp;
}
return( out/2.0f );
return( out * 0.5f );
break;
}
@@ -510,25 +582,29 @@ public:
m_type == Highpass_RC24 )
{
_freq = qBound( 50.0f, _freq, 20000.0f );
m_rca = 1.0f - (1.0f/(m_sampleRate*4)) / ( (1.0f/(_freq*2.0f*M_PI)) + (1.0f/(m_sampleRate*4)) );
const float sr = m_sampleRatio * 0.25f;
const float f = ( _freq * 2.0f * F_PI );
m_rca = 1.0f - sr / ( ( 1.0f / f ) + sr );
m_rcb = 1.0f - m_rca;
m_rcc = (1.0f/(_freq*2.0f*M_PI)) / ( (1.0f/(_freq*2.0f*M_PI)) + (1.0f/(m_sampleRate*4)) );
m_rcc = ( 1.0f / f ) / ( ( 1.0f / f ) + sr );
// Stretch Q/resonance, as self-oscillation reliably starts at a q of ~2.5 - ~2.6
m_rcq = _q * 0.25f;
return;
}
if( m_type == Formantfilter )
if( m_type == Formantfilter ||
m_type == FastFormant )
{
_freq = qBound( minFreq(), _freq, 20000.0f ); // limit freq and q for not getting bad noise out of the filter...
// formats for a, e, i, o, u, a
static const float _f[5][2] = { { 1000, 1400 }, { 500, 2300 },
static const float _f[6][2] = { { 1000, 1400 }, { 500, 2300 },
{ 320, 3200 },
{ 500, 1000 },
{ 320, 800 } };
{ 320, 800 },
{ 1000, 1400 } };
static const float freqRatio = 4.0f / 14000.0f;
// Stretch Q/resonance
@@ -540,24 +616,22 @@ public:
const float fract = vowelf - vowel;
// interpolate between formant frequencies
const float f0 = linearInterpolate( _f[vowel+0][0], _f[vowel+1][0], fract );
const float f1 = linearInterpolate( _f[vowel+0][1], _f[vowel+1][1], fract );
const float f0 = linearInterpolate( _f[vowel+0][0], _f[vowel+1][0], fract ) * 2.0f * F_PI;
const float f1 = linearInterpolate( _f[vowel+0][1], _f[vowel+1][1], fract ) * 2.0f * F_PI;
m_vfa[0] = 1.0f - (1.0f/(m_sampleRate*4)) /
( (1.0f/(f0*2.0f*M_PI)) +
(1.0f/(m_sampleRate*4)) );
// samplerate coeff: depends on oversampling
const float sr = m_type == FastFormant ? m_sampleRatio : m_sampleRatio * 0.25f;
m_vfa[0] = 1.0f - sr /
( ( 1.0f / f0 ) + sr );
m_vfb[0] = 1.0f - m_vfa[0];
m_vfc[0] = (1.0f/(f0*2.0f*M_PI)) /
( (1.0f/(f0*2.0f*M_PI)) +
(1.0f/(m_sampleRate*4)) );
m_vfa[1] = 1.0f - (1.0f/(m_sampleRate*4)) /
( (1.0f/(f1*2.0f*M_PI)) +
(1.0f/(m_sampleRate*4)) );
m_vfc[0] = ( 1.0f / f0 ) /
( ( 1.0f / f0 ) + sr );
m_vfa[1] = 1.0f - sr /
( ( 1.0f / f1 ) + sr );
m_vfb[1] = 1.0f - m_vfa[1];
m_vfc[1] = (1.0f/(f1*2.0f*M_PI)) /
( (1.0f/(f1*2.0f*M_PI)) +
(1.0f/(m_sampleRate*4)) );
m_vfc[1] = ( 1.0f / f1 ) /
( ( 1.0f / f1 ) + sr );
return;
}
@@ -571,7 +645,7 @@ public:
// (Empirical tunning)
m_p = ( 3.6f - 3.2f * f ) * f;
m_k = 2.0f * m_p - 1;
m_r = _q * powf( M_E, ( 1 - m_p ) * 1.386249f );
m_r = _q * powf( F_E, ( 1 - m_p ) * 1.386249f );
if( m_doubleFilter )
{
@@ -581,14 +655,26 @@ public:
}
return;
}
if( m_type == Tripole )
{
const float f = qBound( 20.0f, _freq, 20000.0f ) * m_sampleRatio * 0.25f;
m_p = ( 3.6f - 3.2f * f ) * f;
m_k = 2.0f * m_p - 1.0f;
m_r = _q * 0.1f * powf( F_E, ( 1 - m_p ) * 1.386249f );
return;
}
if( m_type == Lowpass_SV ||
m_type == Bandpass_SV ||
m_type == Highpass_SV )
m_type == Highpass_SV ||
m_type == Notch_SV )
{
const float f = qMax( minFreq(), _freq ) * m_sampleRatio;
m_svf1 = qMin( f * 2.0f, 0.825f );
m_svf2 = qMin( f * 4.0f, 0.825f );
const float f = sinf( qMax( minFreq(), _freq ) * m_sampleRatio * F_PI );
m_svf1 = qMin( f, 0.825f );
m_svf2 = qMin( f * 2.0f, 0.825f );
m_svq = qMax( 0.0001f, 2.0f - ( _q * 0.1995f ) );
return;
}
@@ -598,12 +684,7 @@ public:
const float omega = F_2PI * _freq * m_sampleRatio;
const float tsin = sinf( omega );
const float tcos = cosf( omega );
//float alpha;
//if (q_is_bandwidth)
//alpha = tsin*sinhf(logf(2.0f)/2.0f*q*omega/
// tsin);
//else
const float alpha = 0.5f * tsin / _q;
const float a0 = 1.0f / ( 1.0f + alpha );
@@ -681,6 +762,8 @@ private:
// in/out history for moog-filter
frame m_y1, m_y2, m_y3, m_y4, m_oldx, m_oldy1, m_oldy2, m_oldy3;
// additional one for Tripole filter
frame m_last;
// in/out history for RC-type-filters
frame m_rcbp0, m_rclp0, m_rchp0, m_rclast0;

6
plugins/DualFilter/DualFilterControls.cpp
View File

@@ -78,6 +78,9 @@ DualFilterControls::DualFilterControls( DualFilterEffect* effect ) :
m_filter1Model.addItem( tr( "SV LowPass" ), new PixmapLoader( "filter_lp" ) );
m_filter1Model.addItem( tr( "SV BandPass" ), new PixmapLoader( "filter_bp" ) );
m_filter1Model.addItem( tr( "SV HighPass" ), new PixmapLoader( "filter_hp" ) );
m_filter1Model.addItem( tr( "SV Notch" ), new PixmapLoader( "filter_notch" ) );
m_filter1Model.addItem( tr( "Fast Formant" ), new PixmapLoader( "filter_hp" ) );
m_filter1Model.addItem( tr( "Tripole" ), new PixmapLoader( "filter_lp" ) );
m_filter2Model.addItem( tr( "LowPass" ), new PixmapLoader( "filter_lp" ) );
m_filter2Model.addItem( tr( "HiPass" ), new PixmapLoader( "filter_hp" ) );
@@ -98,6 +101,9 @@ DualFilterControls::DualFilterControls( DualFilterEffect* effect ) :
m_filter2Model.addItem( tr( "SV LowPass" ), new PixmapLoader( "filter_lp" ) );
m_filter2Model.addItem( tr( "SV BandPass" ), new PixmapLoader( "filter_bp" ) );
m_filter2Model.addItem( tr( "SV HighPass" ), new PixmapLoader( "filter_hp" ) );
m_filter2Model.addItem( tr( "SV Notch" ), new PixmapLoader( "filter_notch" ) );
m_filter2Model.addItem( tr( "Fast Formant" ), new PixmapLoader( "filter_hp" ) );
m_filter2Model.addItem( tr( "Tripole" ), new PixmapLoader( "filter_lp" ) );
connect( engine::mixer(), SIGNAL( sampleRateChanged() ), this, SLOT( updateFilters() ) );
}

3
src/core/InstrumentSoundShaping.cpp
View File

@@ -98,6 +98,9 @@ InstrumentSoundShaping::InstrumentSoundShaping(
m_filterModel.addItem( tr( "SV LowPass" ), new PixmapLoader( "filter_lp" ) );
m_filterModel.addItem( tr( "SV BandPass" ), new PixmapLoader( "filter_bp" ) );
m_filterModel.addItem( tr( "SV HighPass" ), new PixmapLoader( "filter_hp" ) );
m_filterModel.addItem( tr( "SV Notch" ), new PixmapLoader( "filter_notch" ) );
m_filterModel.addItem( tr( "Fast Formant" ), new PixmapLoader( "filter_hp" ) );
m_filterModel.addItem( tr( "Tripole" ), new PixmapLoader( "filter_lp" ) );
}