Mixer: Implement plugin spectrum view.

mixer/src/Module.C

@@ -672,6 +672,41 @@ Module::draw_box ( int tx, int ty, int tw, int th )
     fl_pop_clip();
 }
 
+#include "SpectrumView.H"
+#include <FL/Fl_Double_Window.H>
+
+
+bool
+Module::show_analysis_window ( void )
+{
+    nframes_t nframes = 4096;
+    float *buf = new float[nframes];
+
+    if ( ! get_impulse_response( buf, nframes ) )
+        return false;
+    
+    Fl_Double_Window *w = new Fl_Double_Window( 1000, 500 );
+
+    {
+        SpectrumView * o = new SpectrumView( 25,25, 1000 - 50, 500 - 50, label() );
+        o->labelsize(10);
+        o->align(FL_ALIGN_RIGHT|FL_ALIGN_TOP);
+        o->sample_rate( sample_rate() );
+        /* o->minimum_frequency( 10 ); */
+        /* o->maximum_frequency( 50000 ); */
+        o->data( buf, nframes );
+    }
+
+    w->end();
+
+    w->show();
+
+    while ( w->shown() )
+        Fl::wait();
+
+    return true;
+}
+
 void
 Module::draw_label ( int tx, int ty, int tw, int th )
 {
@@ -888,6 +923,10 @@ Module::menu_cb ( const Fl_Menu_ *m )
     {
         paste_before();
     }
+    else if ( ! strcmp( picked, "Show Analysis" ) )
+    {
+        show_analysis_window();
+    }
     else if ( ! strcmp( picked, "Remove" ) )
         command_remove();
 }
@@ -924,10 +963,12 @@ Module::menu ( void ) const
     m.add( "Insert", 0, &Module::menu_cb, (void*)this, 0);
     m.add( "Insert", 0, &Module::menu_cb, const_cast< Fl_Menu_Item *>( insert_menu->menu() ), FL_SUBMENU_POINTER );
     m.add( "Edit Parameters", ' ', &Module::menu_cb, (void*)this, 0 );
+    m.add( "Show Analysis", 's', &Module::menu_cb, (void*)this, 0);
     m.add( "Bypass",   'b', &Module::menu_cb, (void*)this, FL_MENU_TOGGLE | ( bypass() ? FL_MENU_VALUE : 0 ) );
     m.add( "Cut", FL_CTRL + 'x', &Module::menu_cb, (void*)this, is_default() ? FL_MENU_INACTIVE : 0 );
     m.add( "Copy", FL_CTRL + 'c', &Module::menu_cb, (void*)this, is_default() ? FL_MENU_INACTIVE : 0 );
     m.add( "Paste", FL_CTRL + 'v', &Module::menu_cb, (void*)this, _copied_module_empty ? 0 : FL_MENU_INACTIVE );
+
     m.add( "Remove",  FL_Delete, &Module::menu_cb, (void*)this );
 
 //    menu_set_callback( menu, &Module::menu_cb, (void*)this );

mixer/src/Module.H

@@ -441,6 +441,8 @@ public:
     char *get_parameters ( void ) const;
     void set_parameters ( const char * );
 
+    bool show_analysis_window ( void );
+
     void send_feedback ( void );
     virtual bool initialize ( void ) { return true; }
 
@@ -468,6 +470,13 @@ public:
 
     virtual void handle_port_connection_change () {}
 
+    /* module should create a new context, run against this impulse,
+     * and return true if there's anything worth reporting */
+    virtual bool get_impulse_response ( sample_t *buf, nframes_t nframes )
+        {
+            return false;
+        }
+
 #define MODULE_CLONE_FUNC(class)                                \
     virtual Module *clone_empty ( void ) const                  \
         {                                                       \
@@ -480,8 +489,6 @@ public:
 
 protected:
 
-    nframes_t sample_rate ( void ) const { return Module::_sample_rate; }
-
     void draw_connections ( void );
     void draw_label ( int X, int Y, int W, int H );
     void draw_box ( int X, int Y, int W, int H );
@@ -495,6 +502,8 @@ protected:
     bool add_aux_port ( bool input, const char *prefix, int n );
 
 public:
+    nframes_t sample_rate ( void ) const { return Module::_sample_rate; }
+
 
     void auto_connect_outputs();
     void auto_disconnect_outputs();

mixer/src/Module_Parameter_Editor.C

@@ -47,6 +47,8 @@
 #include "FL/menu_popup.H"
 
 
+#include "SpectrumView.H"
+
 Module_Parameter_Editor::Module_Parameter_Editor ( Module *module ) : Fl_Double_Window( 900,240)
 {
     _module = module;
@@ -97,6 +99,7 @@ Module_Parameter_Editor::Module_Parameter_Editor ( Module *module ) : Fl_Double_
                 o->flow( true );
                 o->vspacing( 5 );
                 o->hspacing( 5 );
+                
                 o->end();
             }
             o->resizable( 0 );
@@ -117,6 +120,29 @@ Module_Parameter_Editor::~Module_Parameter_Editor ( )
 
 
 
+void
+Module_Parameter_Editor::update_spectrum ( void )
+{
+    nframes_t nframes = 4096;
+    float *buf = new float[nframes];
+    SpectrumView *o = spectrum_view;
+
+    o->sample_rate( _module->sample_rate() );
+
+    if ( ! _module->get_impulse_response( buf, nframes ) )
+    {
+        o->data( buf, 1 );
+        /* o->hide(); */
+    }
+    else
+    {
+        o->data( buf, nframes );
+        o->parent()->show();
+    }
+
+    o->redraw();
+}
+
 void
 Module_Parameter_Editor::make_controls ( void )
 {
@@ -124,6 +150,17 @@ Module_Parameter_Editor::make_controls ( void )
 
     control_pack->clear();
 
+    { SpectrumView *o = spectrum_view = new SpectrumView( 25, 40, 300, 240, "Spectrum" );
+        o->labelsize(9);
+        o->align(FL_ALIGN_TOP);
+
+
+        Fl_Labelpad_Group *flg = new Fl_Labelpad_Group( (Fl_Widget*)o );
+        flg->hide();
+        control_pack->add( flg );
+    }
+
+
     controls_by_port.clear();
 
     /* these are for detecting related parameter groups which can be
@@ -156,14 +193,14 @@ Module_Parameter_Editor::make_controls ( void )
         control_pack->flow(true);
         control_pack->flowdown(false);
         control_pack->type( FL_HORIZONTAL );
-        control_pack->size( 900, 350 );
+        control_pack->size( 900, 250 );
     }
     else if ( mode_choice->value() == 0 )
     {
         control_pack->vspacing( 10 );
         control_pack->hspacing( 10 );
         control_pack->flow(true);
-        control_pack->flowdown(false);
+        control_pack->flowdown(true);
         control_pack->type( FL_HORIZONTAL );
         control_pack->size( 700, 50 );
         
@@ -382,6 +419,8 @@ Module_Parameter_Editor::make_controls ( void )
 
     update_control_visibility();
     
+    update_spectrum();
+
     control_pack->dolayout();
 
     int width = control_pack->w() + 100;
@@ -504,6 +543,8 @@ Module_Parameter_Editor::handle_control_changed ( Module::Port *p )
     
         v->value( p->control_value() );
     }
+
+    update_spectrum();
 }
 
 
@@ -524,6 +565,8 @@ Module_Parameter_Editor::set_value (int i, float value )
         if ( _module->control_input[i].connected() )
             _module->control_input[i].connected_port()->module()->handle_control_changed( _module->control_input[i].connected_port() );
     }
+
+    update_spectrum();
 //    _module->handle_control_changed( &_module->control_input[i] );
 }
 

mixer/src/Module_Parameter_Editor.H

@@ -27,6 +27,7 @@ class Module;
 class Fl_Menu_Button;
 class Panner;
 class Fl_Scroll;
+class SpectrumView;
 
 #include <vector>
 #include <list>
@@ -76,10 +77,12 @@ class Module_Parameter_Editor : public Fl_Double_Window
     void set_value (int i, float value );
     void bind_control ( int i );
     void make_controls ( void );
+    void update_spectrum ( void );
     
     static void menu_cb ( Fl_Widget *w, void *v );
     void menu_cb ( Fl_Menu_ *m );
 
+    SpectrumView *spectrum_view;
     Fl_Scroll *control_scroll;
     Fl_Flowpack *control_pack;
     Fl_Menu_Button *mode_choice;

mixer/src/Plugin_Module.C

@@ -778,6 +778,80 @@ Plugin_Module::handle_port_connection_change ( void )
 
 
 
+bool 
+Plugin_Module::get_impulse_response ( sample_t *buf, nframes_t nframes )
+{
+    memset( buf, 0, sizeof( float ) * nframes );
+
+    buf[0] = 1;
+    
+    apply( buf, nframes );
+    
+    if ( buffer_is_digital_black( buf + 1, nframes - 1 ))
+        /* no impulse response... */
+        return false;
+
+    return true;
+}
+
+/** Instantiate a temporary version of the plugin, and run it (in place) against the provided buffer */
+bool
+Plugin_Module::apply ( sample_t *buf, nframes_t nframes )
+{
+// actually osc or UI    THREAD_ASSERT( UI );
+
+    LADSPA_Handle h;
+
+    if ( ! (h = _idata->descriptor->instantiate( _idata->descriptor, sample_rate() ) ) )
+    {
+        WARNING( "Failed to instantiate plugin" );
+        return false;
+    }
+
+    int ij = 0;
+    int oj = 0;
+    for ( unsigned int k = 0; k < _idata->descriptor->PortCount; ++k )
+    {
+        if ( LADSPA_IS_PORT_CONTROL( _idata->descriptor->PortDescriptors[k] ) )
+        {
+            if ( LADSPA_IS_PORT_INPUT( _idata->descriptor->PortDescriptors[k] ) )
+                _idata->descriptor->connect_port( h, k, (LADSPA_Data*)control_input[ij++].buffer() );
+            else if ( LADSPA_IS_PORT_OUTPUT( _idata->descriptor->PortDescriptors[k] ) )
+                _idata->descriptor->connect_port( h, k, (LADSPA_Data*)control_output[oj++].buffer() );
+        }
+    }
+    
+    
+    if ( _idata->descriptor->activate )
+        _idata->descriptor->activate( h );
+
+    int tframes = 512;
+    float tmp[tframes];
+
+    memset( tmp, 0, sizeof( float ) * tframes );
+
+    for ( unsigned int k = 0; k < _idata->descriptor->PortCount; ++k )
+        if ( LADSPA_IS_PORT_AUDIO( _idata->descriptor->PortDescriptors[k] ) )
+            _idata->descriptor->connect_port( h, k, tmp );
+    
+
+    /* flush any parameter interpolation */
+    _idata->descriptor->run( h, tframes );
+    
+    for ( unsigned int k = 0; k < _idata->descriptor->PortCount; ++k )
+        if ( LADSPA_IS_PORT_AUDIO( _idata->descriptor->PortDescriptors[k] ) )
+            _idata->descriptor->connect_port( h, k, buf );
+   
+    /* run for real */
+    _idata->descriptor->run( h, nframes );
+    
+    if ( _idata->descriptor->deactivate )
+        _idata->descriptor->deactivate( h );
+    if ( _idata->descriptor->cleanup )
+        _idata->descriptor->cleanup( h );
+
+    return true;
+}
 /**********/
 /* Client */
 /**********/

mixer/src/Plugin_Module.H

@@ -99,6 +99,8 @@ private:
     void set_control_buffer ( int n, void *buf );
     void activate ( void );
     void deactivate ( void );
+    
+    bool apply ( sample_t *buf, nframes_t nframes );
     void process ( unsigned long nframes );
 
     bool plugin_instances ( unsigned int );
@@ -109,6 +111,8 @@ private:
 
 public:
 
+    virtual bool get_impulse_response ( sample_t *buf, nframes_t nframes );
+
     virtual nframes_t get_module_latency ( void ) const;
 
     virtual void update ( void );

mixer/src/SpectrumView.C

@@ -0,0 +1,342 @@
+/*******************************************************************************/
+/* Copyright (C) 2013 Mark McCurry                                             */
+/* Copyright (C) 2013 Jonathan Moore Liles                                     */
+/*                                                                             */
+/* 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 2 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; see the file COPYING.  If not,write to the Free Software */
+/* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+/*******************************************************************************/
+
+#include "SpectrumView.H"
+#include <FL/Fl.H>
+#include <FL/fl_draw.H>
+
+#include <math.h>
+
+#include <cstdlib>
+#include <cstring>
+#include <map>
+
+#include <assert.h>
+
+static std::map<int,float*> _cached_plan;
+
+float SpectrumView::_fmin = 10;
+float SpectrumView::_fmax = 24000;
+unsigned int SpectrumView::_sample_rate = 48000;
+
+
+void
+SpectrumView::clear_bands ( void )
+{
+    if ( _bands )
+        delete[] _bands;
+    
+    _bands = NULL;
+}
+
+void
+SpectrumView::data ( float *data, unsigned int nframes )
+{
+    if ( _data )
+        delete[] _data;
+
+    _data = data;
+    _nframes = nframes;
+
+    clear_bands();
+
+    redraw();
+}
+
+void
+SpectrumView::sample_rate ( unsigned int sample_rate )
+{
+    if ( _sample_rate != sample_rate )
+    {
+        _sample_rate = sample_rate;
+        _fmin = 10;
+        _fmax = _sample_rate * 0.5f;
+
+        /* invalidate all plans */
+
+        for ( std::map<int,float*>::iterator i = _cached_plan.begin();
+              i != _cached_plan.end();
+              i++ )
+        {
+            delete[] i->second;
+        }
+
+        _cached_plan.clear();
+    }
+}
+
+
+#define min(a,b) (a<b?a:b)
+#define max(a,b) (a<b?b:a)
+
+
+static float*
+qft_plan ( unsigned frames, unsigned samples, float Fs, float Fmin, float Fmax )
+{
+    float *op = new float[ frames * samples * 2 ];
+    
+    //Our scaling function must be some f(0) = Fmin and f(1) = Fmax
+    // Thus,
+    // f(x)=10^(a*x+b)  -> b=log(Fmin)/log(10)
+    // log10(Fmax)=a+b  -> a=log(Fmax)/log(10)-b
+    
+    const float b = logf(Fmin)/logf(10);
+    const float a = logf(Fmax)/logf(10)-b;
+
+    //Evaluate at set frequencies
+    const float one_over_samples = 1.0f / samples;
+    const float one_over_samplerate = 1.0f / Fs;
+  
+    for(unsigned i=0; i<samples; ++i) 
+    {
+        const float F = powf(10.0,a*i*one_over_samples+b)*one_over_samplerate;
+        const float Fp = -2*M_PI*F;
+        
+        float Fpj = 0;
+
+        for(unsigned j = 0; j < frames; ++j, Fpj += Fp )
+        {
+            const unsigned ji = i*frames*2+2*j;
+            
+            op[ji+0] = sinf(Fpj);
+            op[ji+1] = cosf(Fpj);
+        }
+    }
+
+    return op;
+}
+
+/** Input should be an impulse response of an EQ. Output will be a
+ * buffer of /bands/ floats of dB values for each frequency band */
+void
+SpectrumView::analyze_data ( unsigned int _plan_size )
+{
+    float res[_plan_size * 2];
+    memset(res,0,sizeof(float) * _plan_size * 2);
+
+    if ( _cached_plan.find( _plan_size ) == _cached_plan.end() )
+        _cached_plan[_plan_size ] = qft_plan( _nframes, _plan_size, _sample_rate, _fmin, _fmax);
+
+    const float *plan = _cached_plan[_plan_size];
+
+    //Evaluate at set frequencies
+    for(unsigned i=0; i<_plan_size; ++i) {
+        unsigned ti = i*2;
+        unsigned tif = ti*_nframes;
+        for(unsigned int j=0; j < _nframes ; ++j) {
+            unsigned ji = tif+j*2;
+
+            res[ti+0] += plan[ji+0]*_data[j];
+            res[ti+1] += plan[ji+1]*_data[j];
+        }
+    }
+
+  
+    float *result = new float[_plan_size];
+    for(unsigned i=0; i<_plan_size; ++i) {
+        const float abs_ = sqrtf(res[2*i]*res[2*i]+res[2*i+1]*res[2*i+1]);
+        result[i] = 20*logf(abs_)/logf(10);
+    }
+    
+    {
+        if ( _auto_level )
+        {
+            /* find range and normalize */
+            float _min=1000, _max=-1000;
+            for(unsigned int i=0; i< _plan_size; ++i)
+            {
+                _min = min(_min, result[i]);
+                _max = max(_max, result[i]);
+            }
+        
+            _dbmin = _min;
+            _dbmax = _max;
+        }
+    
+        double minS = 1.0 / (_dbmax-_dbmin);
+
+        for( unsigned int i=0; i<_plan_size; ++i)
+            result[i] = (result[i]-_dbmin)*minS;
+    }
+
+    clear_bands();
+        
+    _bands = result;
+}
+
+SpectrumView::~SpectrumView ( void )
+{
+    clear_bands();
+    if ( _data )
+        delete[] _data;
+}
+
+SpectrumView::SpectrumView ( int X, int Y, int W, int H, const char *L )
+    : Fl_Box(X,Y,W,H,L)
+{
+    _auto_level = 0;
+    _data = 0;
+    _nframes = 0;
+    _bands = 0;
+    _dbmin = -70;
+    _dbmax = 30;
+    box(FL_FLAT_BOX); 
+    color(fl_rgb_color(20,20,20));
+    selection_color( fl_rgb_color( 210, 80, 80 ) );
+//    end();
+}
+
+static int padding_right = 0;
+static int padding_bottom = 0;
+
+void 
+SpectrumView::draw_semilog ( void )
+{
+    int W = w() - padding_right;
+    int H = h() - padding_bottom;
+
+    /* char dash[] = {5,5 }; */
+    /* fl_line_style(0, 1, dash); */
+    fl_line_style(FL_SOLID,0);
+
+    //Db grid is easy, it is just a linear spacing
+    for(int i=0; i<8; ++i) {
+        int level = y()+H*i/8.0;
+        fl_line(x(), level, x()+W, level);
+    }
+
+    //The frequency grid is defined with points at
+    //10,11,12,...,18,19,20,30,40,50,60,70,80,90,100,200,400,...
+    //Thus we find each scale that we cover and draw the nine lines unique to
+    //that scale
+    const int min_base = logf(_fmin)/logf(10);
+    const int max_base = logf(_fmax)/logf(10);
+    const float b = logf(_fmin)/logf(10);
+    const float a = logf(_fmax)/logf(10)-b;
+    for(int i=min_base; i<=max_base; ++i) {
+        for(int j=1; j<10; ++j) {
+            const float freq = pow(10.0, i)*j;
+            const float xloc = (logf(freq)/logf(10)-b)/a;
+            if(xloc<1.0 && xloc > -0.001)
+                fl_line(xloc*W+x(), y(), xloc*W+x(), y()+H);
+        }
+    }
+
+    fl_end_line();
+            
+    fl_font( FL_HELVETICA_ITALIC, 7 );
+    //Place the text labels
+    char label[256];
+    for(int i=0; i<8; ++i) {
+        int level = (y()+H*i/8.0) + 3;
+        float value = (1-i/8.0)*(_dbmax-_dbmin) + _dbmin;
+        sprintf(label, "%.1f dB", value);
+//        fl_draw(label, x()+w() + 3, level);
+        fl_draw(label, x(), level, w(), 7, FL_ALIGN_RIGHT );
+    }
+            
+    for(int i=min_base; i<=max_base; ++i) {
+        {
+            const float freq = pow(10.0, i)*1;
+            const float xloc = (logf(freq)/logf(10)-b)/a;
+            sprintf(label, "%0.f %s", freq < 1000.0 ? freq : freq / 1000.0, freq < 1000.0 ? "Hz" : "KHz" );
+            if(xloc<1.0)
+                fl_draw(label, xloc*W+x()+1, y()+h());
+        }
+    }
+}
+
+void
+SpectrumView::draw_curve ( void )
+{
+    int W = w() - padding_right;
+
+    //Build lines
+    float inc = 1.0 / (float)W;
+
+    float fx = 0;
+    for(  int i = 0; i < W; i++, fx += inc )
+        fl_vertex(fx, 1.0 - _bands[i]);
+}
+
+void
+SpectrumView::draw ( void ) 
+{
+    //Clear Widget
+    Fl_Box::draw();
+
+    int W = w() - padding_right;
+    int H = h() - padding_bottom;
+    
+    if ( !_bands ) {
+        analyze_data( W );
+    }
+
+    //Draw grid
+    fl_color(fl_color_add_alpha(fl_rgb_color( 100,100,100), 50 ));
+
+    draw_semilog();
+
+    fl_push_clip( x(),y(),W,H);
+
+            
+    fl_color(fl_color_add_alpha( selection_color(), 20 ));
+   
+    fl_push_matrix();
+    fl_translate( x(), y() + 2 );
+    fl_scale( W,H- 2 );
+
+    fl_begin_polygon();
+    
+    fl_vertex(0.0,1.0);
+
+    draw_curve();
+
+    fl_vertex(1.0,1.0);
+                  
+    fl_end_polygon();
+
+    fl_color(fl_color_add_alpha( selection_color(), 100 ));
+    fl_begin_line();
+    fl_line_style(FL_SOLID,2);
+    
+    /* fl_vertex(0.0,1.0); */
+
+    draw_curve();
+
+    /* fl_vertex(1.0,1.0); */
+
+    fl_end_line();
+    
+    fl_pop_matrix();
+
+    fl_line_style(FL_SOLID,0);
+
+    fl_pop_clip();
+}
+
+void
+SpectrumView::resize ( int X, int Y, int W, int H )
+{
+    if ( W != w() )
+        clear_bands();
+
+    Fl_Box::resize(X,Y,W,H);
+}
+

mixer/src/SpectrumView.H

@@ -0,0 +1,62 @@
+
+/*******************************************************************************/
+/* Copyright (C) 2013 Mark McCurry                                             */
+/* Copyright (C) 2013 Jonathan Moore Liles                                     */
+/*                                                                             */
+/* 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 2 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; see the file COPYING.  If not,write to the Free Software */
+/* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+/*******************************************************************************/
+
+#include <FL/Fl_Box.H>
+
+class SpectrumView : public Fl_Box
+{
+    static unsigned int _sample_rate;
+    static float _fmin;
+    static float _fmax;
+
+    float * _data;
+    unsigned int _nframes;
+    float * _bands;
+    float _dbmin;
+    float _dbmax;
+    bool _auto_level;
+
+    void draw_curve ( void );
+    void draw_semilog ( void );
+    void analyze_data ( unsigned int plan_size );
+    void clear_bands ( void );
+
+public:
+    
+    static void sample_rate ( unsigned int sample_rate );
+
+    /* set dB range. If min == max, then auto leveling will be enabled */
+    void db_range ( float min, float max )
+        {
+            _dbmin = min;
+            _dbmax = max;
+            _auto_level = min == max;
+        }
+
+    /** /data/ must point to allocated memory. It will be freed when new data is set or when the control is destroyed */
+    void data ( float *data, unsigned int nframes );
+
+    SpectrumView ( int X, int Y, int W, int H, const char *L=0 );
+    virtual ~SpectrumView ( );
+
+    virtual void resize ( int X, int Y, int W, int H );
+    virtual void draw ( void );
+};
+

mixer/wscript

@@ -66,6 +66,7 @@ src/Plugin_Module.C
 src/Project.C
 src/Group.C
 src/main.C
+src/SpectrumView.C
 src/Spatialization_Console.C
 ''',
               target       = 'non-mixer',

nonlib/dsp.C

@@ -181,7 +181,7 @@ buffer_fill_with_silence ( sample_t *buf, nframes_t nframes )
 }
 
 bool
-buffer_is_digital_black ( sample_t *buf, nframes_t nframes )
+buffer_is_digital_black ( const sample_t *buf, nframes_t nframes )
 {
     while ( nframes-- )
     {