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 <unistd.h>
  16 #include <inttypes.h>
  17 #include <math.h>
  18 #include <limits.h>
  19
  20 #include "af.h"
  21
  22 // Data for specific instances of this filter
  23 typedef struct af_gate_s
  24 {
  25   int   enable[AF_NCH];         // Enable/disable / channel
  26   float time[AF_NCH];           // Forgetting factor for power estimate
  27   float pow[AF_NCH];            // Estimated power level [dB]
  28   float tresh[AF_NCH];          // Threshold [dB]
  29   int   attack[AF_NCH];         // Attack time [ms]
  30   int   release[AF_NCH];        // Release time [ms]
  31   float range[AF_NCH];          // Range level [dB]
  32 }af_gate_t;
  33
  34 // Initialization and runtime control
  35 static int control(struct af_instance_s* af, int cmd, void* arg)
  36 {
  37   af_gate_t* s   = (af_gate_t*)af->setup;
  38   switch(cmd){
  39   case AF_CONTROL_REINIT:
  40     // Sanity check
  41     if(!arg) return AF_ERROR;
  42
  43     af->data->rate   = ((af_data_t*)arg)->rate;
  44     af->data->nch    = ((af_data_t*)arg)->nch;
  45     af->data->format = AF_FORMAT_FLOAT_NE;
  46     af->data->bps    = 4;
  47
  48     // Time constant set to 0.1s
  49     //    s->alpha = (1.0/0.2)/(2.0*M_PI*(float)((af_data_t*)arg)->rate);
  50     return af_test_output(af,(af_data_t*)arg);
  51   case AF_CONTROL_COMMAND_LINE:{
  52 /*     float v=-10.0; */
  53 /*     float vol[AF_NCH]; */
  54 /*     float s=0.0; */
  55 /*     float clipp[AF_NCH]; */
  56 /*     int i; */
  57 /*     sscanf((char*)arg,"%f:%f", &v, &s); */
  58 /*     for(i=0;i<AF_NCH;i++){ */
  59 /*       vol[i]=v; */
  60 /*       clipp[i]=s; */
  61 /*     } */
  62 /*     if(AF_OK != control(af,AF_CONTROL_VOLUME_SOFTCLIP | AF_CONTROL_SET, clipp)) */
  63 /*       return AF_ERROR; */
  64 /*     return control(af,AF_CONTROL_VOLUME_LEVEL | AF_CONTROL_SET, vol); */
  65   }
  66
  67   case AF_CONTROL_GATE_ON_OFF | AF_CONTROL_SET:
  68     memcpy(s->enable,(int*)arg,AF_NCH*sizeof(int));
  69     return AF_OK;
  70   case AF_CONTROL_GATE_ON_OFF | AF_CONTROL_GET:
  71     memcpy((int*)arg,s->enable,AF_NCH*sizeof(int));
  72     return AF_OK;
  73   case AF_CONTROL_GATE_THRESH | AF_CONTROL_SET:
  74     return af_from_dB(AF_NCH,(float*)arg,s->tresh,20.0,-60.0,-1.0);
  75   case AF_CONTROL_GATE_THRESH | AF_CONTROL_GET:
  76     return af_to_dB(AF_NCH,s->tresh,(float*)arg,10.0);
  77   case AF_CONTROL_GATE_ATTACK | AF_CONTROL_SET:
  78     return af_from_ms(AF_NCH,(float*)arg,s->attack,af->data->rate,500.0,0.1);
  79   case AF_CONTROL_GATE_ATTACK | AF_CONTROL_GET:
  80     return af_to_ms(AF_NCH,s->attack,(float*)arg,af->data->rate);
  81   case AF_CONTROL_GATE_RELEASE | AF_CONTROL_SET:
  82     return af_from_ms(AF_NCH,(float*)arg,s->release,af->data->rate,3000.0,10.0);
  83   case AF_CONTROL_GATE_RELEASE | AF_CONTROL_GET:
  84     return af_to_ms(AF_NCH,s->release,(float*)arg,af->data->rate);
  85   case AF_CONTROL_GATE_RANGE | AF_CONTROL_SET:
  86     return af_from_dB(AF_NCH,(float*)arg,s->range,20.0,100.0,0.0);
  87   case AF_CONTROL_GATE_RANGE | AF_CONTROL_GET:
  88     return af_to_dB(AF_NCH,s->range,(float*)arg,10.0);
  89   }
  90   return AF_UNKNOWN;
  91 }
  92
  93 // Deallocate memory
  94 static void uninit(struct af_instance_s* af)
  95 {
  96   if(af->data)
  97     free(af->data);
  98   if(af->setup)
  99     free(af->setup);
 100 }
 101
 102 // Filter data through filter
 103 static af_data_t* play(struct af_instance_s* af, af_data_t* data)
 104 {
 105   af_data_t*    c   = data;                     // Current working data
 106   af_gate_t*    s   = (af_gate_t*)af->setup;    // Setup for this instance
 107   float*        a   = (float*)c->audio;         // Audio data
 108   int           len = c->len/4;                 // Number of samples
 109   int           ch  = 0;                        // Channel counter
 110   register int  nch = c->nch;                   // Number of channels
 111   register int  i   = 0;
 112
 113
 114   // Noise gate
 115   for(ch = 0; ch < nch ; ch++){
 116     if(s->enable[ch]){
 117       float     t   = 1.0 - s->time[ch];
 118       for(i=ch;i<len;i+=nch){
 119         register float x        = a[i];
 120         register float pow      = x*x;
 121         s->pow[ch] = t*s->pow[ch] +
 122           pow*s->time[ch]; // LP filter
 123         if(pow < s->pow[ch]){
 124           ;
 125         }
 126         else{
 127           ;
 128         }
 129         a[i] = x;
 130       }
 131     }
 132   }
 133   return c;
 134 }
 135
 136 // Allocate memory and set function pointers
 137 static int open(af_instance_t* af){
 138   af->control=control;
 139   af->uninit=uninit;
 140   af->play=play;
 141   af->mul.n=1;
 142   af->mul.d=1;
 143   af->data=calloc(1,sizeof(af_data_t));
 144   af->setup=calloc(1,sizeof(af_gate_t));
 145   if(af->data == NULL || af->setup == NULL)
 146     return AF_ERROR;
 147   return AF_OK;
 148 }
 149
 150 // Description of this filter
 151 af_info_t af_info_gate = {
 152     "Noise gate audio filter",
 153     "gate",
 154     "Anders",
 155     "",
 156     AF_FLAGS_NOT_REENTRANT,
 157     open
 158 };