libaf/af_gate.c

   1 /*=============================================================================
   2 //
   3 //  This software has been released under the terms of the GNU General Public
   4 //  license. See http://www.gnu.org/copyleft/gpl.html for details.
   5 //
   6 //  Copyright 2002 Anders Johansson ajh@atri.curtin.edu.au
   7 //
   8 //=============================================================================
   9 */
  10
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14
  15 #include <inttypes.h>
  16 #include <math.h>
  17 #include <limits.h>
  18
  19 #include "af.h"
  20
  21 // Data for specific instances of this filter
  22 typedef struct af_gate_s
  23 {
  24   int   enable[AF_NCH];         // Enable/disable / channel
  25   float time[AF_NCH];           // Forgetting factor for power estimate
  26   float pow[AF_NCH];            // Estimated power level [dB]
  27   float tresh[AF_NCH];          // Threshold [dB]
  28   int   attack[AF_NCH];         // Attack time [ms]
  29   int   release[AF_NCH];        // Release time [ms]
  30   float range[AF_NCH];          // Range level [dB]
  31 }af_gate_t;
  32
  33 // Initialization and runtime control
  34 static int control(struct af_instance_s* af, int cmd, void* arg)
  35 {
  36   af_gate_t* s   = (af_gate_t*)af->setup;
  37   switch(cmd){
  38   case AF_CONTROL_REINIT:
  39     // Sanity check
  40     if(!arg) return AF_ERROR;
  41
  42     af->data->rate   = ((af_data_t*)arg)->rate;
  43     af->data->nch    = ((af_data_t*)arg)->nch;
  44     af->data->format = AF_FORMAT_FLOAT_NE;
  45     af->data->bps    = 4;
  46
  47     // Time constant set to 0.1s
  48     //    s->alpha = (1.0/0.2)/(2.0*M_PI*(float)((af_data_t*)arg)->rate);
  49     return af_test_output(af,(af_data_t*)arg);
  50   case AF_CONTROL_COMMAND_LINE:{
  51 /*     float v=-10.0; */
  52 /*     float vol[AF_NCH]; */
  53 /*     float s=0.0; */
  54 /*     float clipp[AF_NCH]; */
  55 /*     int i; */
  56 /*     sscanf((char*)arg,"%f:%f", &v, &s); */
  57 /*     for(i=0;i<AF_NCH;i++){ */
  58 /*       vol[i]=v; */
  59 /*       clipp[i]=s; */
  60 /*     } */
  61 /*     if(AF_OK != control(af,AF_CONTROL_VOLUME_SOFTCLIP | AF_CONTROL_SET, clipp)) */
  62 /*       return AF_ERROR; */
  63 /*     return control(af,AF_CONTROL_VOLUME_LEVEL | AF_CONTROL_SET, vol); */
  64   }
  65
  66   case AF_CONTROL_GATE_ON_OFF | AF_CONTROL_SET:
  67     memcpy(s->enable,(int*)arg,AF_NCH*sizeof(int));
  68     return AF_OK;
  69   case AF_CONTROL_GATE_ON_OFF | AF_CONTROL_GET:
  70     memcpy((int*)arg,s->enable,AF_NCH*sizeof(int));
  71     return AF_OK;
  72   case AF_CONTROL_GATE_THRESH | AF_CONTROL_SET:
  73     return af_from_dB(AF_NCH,(float*)arg,s->tresh,20.0,-60.0,-1.0);
  74   case AF_CONTROL_GATE_THRESH | AF_CONTROL_GET:
  75     return af_to_dB(AF_NCH,s->tresh,(float*)arg,10.0);
  76   case AF_CONTROL_GATE_ATTACK | AF_CONTROL_SET:
  77     return af_from_ms(AF_NCH,(float*)arg,s->attack,af->data->rate,500.0,0.1);
  78   case AF_CONTROL_GATE_ATTACK | AF_CONTROL_GET:
  79     return af_to_ms(AF_NCH,s->attack,(float*)arg,af->data->rate);
  80   case AF_CONTROL_GATE_RELEASE | AF_CONTROL_SET:
  81     return af_from_ms(AF_NCH,(float*)arg,s->release,af->data->rate,3000.0,10.0);
  82   case AF_CONTROL_GATE_RELEASE | AF_CONTROL_GET:
  83     return af_to_ms(AF_NCH,s->release,(float*)arg,af->data->rate);
  84   case AF_CONTROL_GATE_RANGE | AF_CONTROL_SET:
  85     return af_from_dB(AF_NCH,(float*)arg,s->range,20.0,100.0,0.0);
  86   case AF_CONTROL_GATE_RANGE | AF_CONTROL_GET:
  87     return af_to_dB(AF_NCH,s->range,(float*)arg,10.0);
  88   }
  89   return AF_UNKNOWN;
  90 }
  91
  92 // Deallocate memory
  93 static void uninit(struct af_instance_s* af)
  94 {
  95   if(af->data)
  96     free(af->data);
  97   if(af->setup)
  98     free(af->setup);
  99 }
 100
 101 // Filter data through filter
 102 static af_data_t* play(struct af_instance_s* af, af_data_t* data)
 103 {
 104   af_data_t*    c   = data;                     // Current working data
 105   af_gate_t*    s   = (af_gate_t*)af->setup;    // Setup for this instance
 106   float*        a   = (float*)c->audio;         // Audio data
 107   int           len = c->len/4;                 // Number of samples
 108   int           ch  = 0;                        // Channel counter
 109   register int  nch = c->nch;                   // Number of channels
 110   register int  i   = 0;
 111
 112
 113   // Noise gate
 114   for(ch = 0; ch < nch ; ch++){
 115     if(s->enable[ch]){
 116       float     t   = 1.0 - s->time[ch];
 117       for(i=ch;i<len;i+=nch){
 118         register float x        = a[i];
 119         register float pow      = x*x;
 120         s->pow[ch] = t*s->pow[ch] +
 121           pow*s->time[ch]; // LP filter
 122         if(pow < s->pow[ch]){
 123           ;
 124         }
 125         else{
 126           ;
 127         }
 128         a[i] = x;
 129       }
 130     }
 131   }
 132   return c;
 133 }
 134
 135 // Allocate memory and set function pointers
 136 static int af_open(af_instance_t* af){
 137   af->control=control;
 138   af->uninit=uninit;
 139   af->play=play;
 140   af->mul=1;
 141   af->data=calloc(1,sizeof(af_data_t));
 142   af->setup=calloc(1,sizeof(af_gate_t));
 143   if(af->data == NULL || af->setup == NULL)
 144     return AF_ERROR;
 145   return AF_OK;
 146 }
 147
 148 // Description of this filter
 149 af_info_t af_info_gate = {
 150     "Noise gate audio filter",
 151     "gate",
 152     "Anders",
 153     "",
 154     AF_FLAGS_NOT_REENTRANT,
 155     af_open
 156 };