mpv/libaf/af_sinesuppress.c

/*=============================================================================
//	
//  This software has been released under the terms of the GNU General Public
//  license. See http://www.gnu.org/copyleft/gpl.html for details.
//
//  Copyright 2006 Michael Niedermayer
//  Copyright 2004 Alex Beregszaszi & Pierre Lombard (original af_extrastereo.c upon which this is based)
//
//=============================================================================
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h> 

#include <unistd.h>
#include <inttypes.h>
#include <math.h>
#include <limits.h>

#include "af.h"

// Data for specific instances of this filter
typedef struct af_sinesuppress_s
{
    double freq;
    double decay;
    double real;
    double imag;
    double ref;
    double pos;
}af_sinesuppress_t;

static af_data_t* play_s16(struct af_instance_s* af, af_data_t* data);
static af_data_t* play_float(struct af_instance_s* af, af_data_t* data);

// Initialization and runtime control
static int control(struct af_instance_s* af, int cmd, void* arg)
{
  af_sinesuppress_t* s   = (af_sinesuppress_t*)af->setup; 

  switch(cmd){
  case AF_CONTROL_REINIT:{
    // Sanity check
    if(!arg) return AF_ERROR;
    
    af->data->rate   = ((af_data_t*)arg)->rate;
    af->data->nch    = 1;
#if 0
    if (((af_data_t*)arg)->format == AF_FORMAT_FLOAT_NE)
    {
	af->data->format = AF_FORMAT_FLOAT_NE;
	af->data->bps = 4;
	af->play = play_float;
    }// else
#endif
    {
	af->data->format = AF_FORMAT_S16_NE;
	af->data->bps = 2;
	af->play = play_s16;
    }

    return af_test_output(af,(af_data_t*)arg);
  }
  case AF_CONTROL_COMMAND_LINE:{
    float f1,f2;
    sscanf((char*)arg,"%f:%f", &f1,&f2);
    s->freq = f1;
    s->decay = f2;
    return AF_OK;
  }
  case AF_CONTROL_SS_FREQ | AF_CONTROL_SET:
    s->freq = *(float*)arg;
    return AF_OK;
  case AF_CONTROL_SS_FREQ | AF_CONTROL_GET:
    *(float*)arg = s->freq;
    return AF_OK;
  case AF_CONTROL_SS_DECAY | AF_CONTROL_SET:
    s->decay = *(float*)arg;
    return AF_OK;
  case AF_CONTROL_SS_DECAY | AF_CONTROL_GET:
    *(float*)arg = s->decay;
    return AF_OK;
  }
  return AF_UNKNOWN;
}

// Deallocate memory 
static void uninit(struct af_instance_s* af)
{
  if(af->data)
    free(af->data);
  if(af->setup)
    free(af->setup);
}

// Filter data through filter
static af_data_t* play_s16(struct af_instance_s* af, af_data_t* data)
{
  af_sinesuppress_t *s = af->setup;
  register int i = 0;
  int16_t *a = (int16_t*)data->audio;	// Audio data
  int len = data->len/2;		// Number of samples
  int avg, l, r;
  
  for (i = 0; i < len; i++)
  {
    double co= cos(s->pos);
    double si= sin(s->pos);

    s->real += co * a[i];
    s->imag += si * a[i];
    s->ref  += co * co;

    a[i] -= (s->real * co + s->imag * si) / s->ref;

    s->real -= s->real * s->decay;
    s->imag -= s->imag * s->decay;
    s->ref  -= s->ref  * s->decay;

    s->pos += 2 * M_PI * s->freq / data->rate;
  }

   af_msg(AF_MSG_VERBOSE,"[sinesuppress] f:%8.2f: amp:%8.2f\n", s->freq, sqrt(s->real*s->real + s->imag*s->imag) / s->ref);

  return data;
}

#if 0
static af_data_t* play_float(struct af_instance_s* af, af_data_t* data)
{
  af_sinesuppress_t *s = af->setup;
  register int i = 0;
  float *a = (float*)data->audio;	// Audio data
  int len = data->len/4;		// Number of samples
  float avg, l, r;
  
  for (i = 0; i < len; i+=2)
  {
    avg = (a[i] + a[i + 1]) / 2;
    
/*    l = avg + (s->mul * (a[i] - avg));
    r = avg + (s->mul * (a[i + 1] - avg));*/
    
    a[i] = af_softclip(l);
    a[i + 1] = af_softclip(r);
  }

  return data;
}
#endif

// Allocate memory and set function pointers
static int open(af_instance_t* af){
  af->control=control;
  af->uninit=uninit;
  af->play=play_s16;
  af->mul.n=1;
  af->mul.d=1;
  af->data=calloc(1,sizeof(af_data_t));
  af->setup=calloc(1,sizeof(af_sinesuppress_t));
  if(af->data == NULL || af->setup == NULL)
    return AF_ERROR;

  ((af_sinesuppress_t*)af->setup)->freq = 50.0;
  ((af_sinesuppress_t*)af->setup)->decay = 0.0001;
  return AF_OK;
}

// Description of this filter
af_info_t af_info_sinesuppress = {
    "Sine Suppress",
    "sinesuppress",
    "Michael Niedermayer",
    "",
    0,
    open
};