libaf/af_tools.c

   1 /*
   2  * This file is part of MPlayer.
   3  *
   4  * MPlayer is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * MPlayer is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #include <math.h>
  20 #include <string.h>
  21 #include "af.h"
  22
  23 /* Convert to gain value from dB. Returns AF_OK if of and AF_ERROR if
  24    fail */
  25 int af_from_dB(int n, float* in, float* out, float k, float mi, float ma)
  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]<=-200)
  34       out[i]=0.0;
  35     else
  36       out[i]=pow(10.0,clamp(in[i],mi,ma)/k);
  37   }
  38   return AF_OK;
  39 }
  40
  41 /* Convert from gain value to dB. Returns AF_OK if of and AF_ERROR if
  42    fail */
  43 int af_to_dB(int n, float* in, float* out, float k)
  44 {
  45   int i = 0;
  46   // Sanity check
  47   if(!in || !out)
  48     return AF_ERROR;
  49
  50   for(i=0;i<n;i++){
  51     if(in[i] == 0.0)
  52       out[i]=-200.0;
  53     else
  54       out[i]=k*log10(in[i]);
  55   }
  56   return AF_OK;
  57 }
  58
  59 /* Convert from ms to sample time */
  60 int af_from_ms(int n, float* in, int* out, int rate, float mi, float ma)
  61 {
  62   int i = 0;
  63   // Sanity check
  64   if(!in || !out)
  65     return AF_ERROR;
  66
  67   for(i=0;i<n;i++)
  68     out[i]=(int)((float)rate * clamp(in[i],mi,ma)/1000.0);
  69
  70   return AF_OK;
  71 }
  72
  73 /* Convert from sample time to ms */
  74 int af_to_ms(int n, int* in, float* out, int rate)
  75 {
  76   int i = 0;
  77   // Sanity check
  78   if(!in || !out || !rate)
  79     return AF_ERROR;
  80
  81   for(i=0;i<n;i++)
  82     out[i]=1000.0 * (float)in[i]/((float)rate);
  83
  84   return AF_OK;
  85 }
  86
  87 /* Helper function for testing the output format */
  88 int af_test_output(struct af_instance_s* af, af_data_t* out)
  89 {
  90   if((af->data->format != out->format) ||
  91      (af->data->bps    != out->bps)    ||
  92      (af->data->rate   != out->rate)   ||
  93      (af->data->nch    != out->nch)){
  94     memcpy(out,af->data,sizeof(af_data_t));
  95     return AF_FALSE;
  96   }
  97   return AF_OK;
  98 }
  99
 100 /* Soft clipping, the sound of a dream, thanks to Jon Wattes
 101    post to Musicdsp.org */
 102 float af_softclip(float a)
 103 {
 104     if (a >= M_PI/2)
 105         return 1.0;
 106     else if (a <= -M_PI/2)
 107         return -1.0;
 108     else
 109         return sin(a);
 110 }