libaf/af_tools.c

   1 #include <math.h>
   2 #include <string.h>
   3 #include <af.h>
   4
   5 /* Convert to gain value from dB. Returns AF_OK if of and AF_ERROR if
   6    fail */
   7 int af_from_dB(int n, float* in, float* out, float k, float mi, float ma)
   8 {
   9   int i = 0;
  10   // Sanity check
  11   if(!in || !out)
  12     return AF_ERROR;
  13
  14   for(i=0;i<n;i++){
  15     if(in[i]<=-200)
  16       out[i]=0.0;
  17     else
  18       out[i]=pow(10.0,clamp(in[i],mi,ma)/k);
  19   }
  20   return AF_OK;
  21 }
  22
  23 /* Convert from gain value to dB. Returns AF_OK if of and AF_ERROR if
  24    fail */
  25 int af_to_dB(int n, float* in, float* out, float k)
  26 {
  27   int i = 0;
  28   // Sanity check
  29   if(!in || !out)
  30     return AF_ERROR;
  31
  32   for(i=0;i<n;i++){
  33     if(in[i] == 0.0)
  34       out[i]=-200.0;
  35     else
  36       out[i]=k*log10(in[i]);
  37   }
  38   return AF_OK;
  39 }
  40
  41 /* Convert from ms to sample time */
  42 int af_from_ms(int n, float* in, int* out, int rate, float mi, float ma)
  43 {
  44   int i = 0;
  45   // Sanity check
  46   if(!in || !out)
  47     return AF_ERROR;
  48
  49   for(i=0;i<n;i++)
  50     out[i]=(int)((float)rate * clamp(in[i],mi,ma)/1000.0);
  51
  52   return AF_OK;
  53 }
  54
  55 /* Convert from sample time to ms */
  56 int af_to_ms(int n, int* in, float* out, int rate)
  57 {
  58   int i = 0;
  59   // Sanity check
  60   if(!in || !out || !rate)
  61     return AF_ERROR;
  62
  63   for(i=0;i<n;i++)
  64     out[i]=1000.0 * (float)in[i]/((float)rate);
  65
  66   return AF_OK;
  67 }
  68
  69 /* Helper function for testing the output format */
  70 int af_test_output(struct af_instance_s* af, af_data_t* out)
  71 {
  72   if((af->data->format != out->format) ||
  73      (af->data->bps    != out->bps)    ||
  74      (af->data->rate   != out->rate)   ||
  75      (af->data->nch    != out->nch)){
  76     memcpy(out,af->data,sizeof(af_data_t));
  77     return AF_FALSE;
  78   }
  79   return AF_OK;
  80 }
  81
  82 /* Soft clipping, the sound of a dream, thanks to Jon Wattes
  83    post to Musicdsp.org */
  84 float af_softclip(float a)
  85 {
  86     if (a >= M_PI/2)
  87         return 1.0;
  88     else if (a <= -M_PI/2)
  89         return -1.0;
  90     else
  91         return sin(a);
  92 }