equalization.cpp

使用软件的实现EQ均衡器算法

/*
 * MoreAmp
 * Copyright (C) 2004-2006 pmisteli
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

// this code contains extracts fromeq-xmms plugin
/*
 *   PCM time-domain equalizer
 *   Copyright (C) 2002  Felipe Rivera <liebremx at users sourceforge net>
 *   $Id: iir.c,v 1.5 2003/09/10 21:53:08 liebremx Exp $
 */

#include "stdafx.h"

#ifdef __cplusplus
extern "C"
{
#endif

#include <stdio.h>
#include <string.h>
#include <limits.h> // for SHRT_MAX
#include <math.h>

#include "Equalization.h"

int eq31EqualizeBlock(void* pcmblock, unsigned long pcmblocksize);
int eq31EqualizerSetLevel(int band, double factor);
int eq31Init(int bands, int bits16, int extra);

typedef short gint16;
typedef void* gpointer;

/* Floating point */
typedef struct 
{
	float beta;
	float alpha; 
	float gamma;
}sIIRCoefficients;

/* Coefficient history for the IIR filter */
typedef struct
{
	float x[3]; /* x[n], x[n-1], x[n-2] */
	float y[3]; /* y[n], y[n-1], y[n-2] */
}sXYData;

int iir(gpointer * d, magint length);

static sIIRCoefficients iir_cf2[]
= {
	{ (float)(6.6857185264e-01), (float)(1.6571407368e-01), (float)(1.4048592171e+00) },	//  4000.0 Hz
	{ (float)(4.4861333678e-01), (float)(2.7569333161e-01), (float)(6.0518718075e-01) },	//  8000.0 Hz
};

static sIIRCoefficients iir_cf3[]
= {
	{ (float)(8.1778971701e-01), (float)(9.1105141497e-02), (float)(1.7444877599e+00) },	//  2000.0 Hz
	{ (float)(6.6857185264e-01), (float)(1.6571407368e-01), (float)(1.4048592171e+00) },	//  4000.0 Hz
	{ (float)(4.4861333678e-01), (float)(2.7569333161e-01), (float)(6.0518718075e-01) },	//  8000.0 Hz
};

static sIIRCoefficients iir_cf5[]
= {
	{ (float)(9.5105628526e-01), (float)(2.4471857368e-02), (float)(1.9461077269e+00) },	//   500.0 Hz
	{ (float)(9.0450844499e-01), (float)(4.7745777504e-02), (float)(1.8852109613e+00) },	//  1000.0 Hz
	{ (float)(8.1778971701e-01), (float)(9.1105141497e-02), (float)(1.7444877599e+00) },	//  2000.0 Hz
	{ (float)(6.6857185264e-01), (float)(1.6571407368e-01), (float)(1.4048592171e+00) },	//  4000.0 Hz
	{ (float)(4.4861333678e-01), (float)(2.7569333161e-01), (float)(6.0518718075e-01) },	//  8000.0 Hz
};

static sIIRCoefficients iir_cf10[]
= {
	{ (float)(9.9723137967e-01), (float)(1.3843101653e-03), (float)(1.9972115835e+00) },	//	 31.2 Hz
	{ (float)(9.9406142155e-01), (float)(2.9692892229e-03), (float)(1.9939823631e+00) },	//	 62.5 Hz
	{ (float)(9.8774277725e-01), (float)(6.1286113769e-03), (float)(1.9874275518e+00) },	//   125.0 Hz
	{ (float)(9.7522112569e-01), (float)(1.2389437156e-02), (float)(1.9739682661e+00) },	//   250.0 Hz
	{ (float)(9.5105628526e-01), (float)(2.4471857368e-02), (float)(1.9461077269e+00) },	//   500.0 Hz
	{ (float)(9.0450844499e-01), (float)(4.7745777504e-02), (float)(1.8852109613e+00) },	//  1000.0 Hz
	{ (float)(8.1778971701e-01), (float)(9.1105141497e-02), (float)(1.7444877599e+00) },	//  2000.0 Hz
	{ (float)(6.6857185264e-01), (float)(1.6571407368e-01), (float)(1.4048592171e+00) },	//  4000.0 Hz
	{ (float)(4.4861333678e-01), (float)(2.7569333161e-01), (float)(6.0518718075e-01) },	//  8000.0 Hz
	{ (float)(2.4201241845e-01), (float)(3.7899379077e-01), (float)(-8.0847117831e-01) },	// 16000.0 Hz
};

static sIIRCoefficients iir_cf31[]
= {
	{ (float)(9.9939854113e-01), (float)(3.0072943419e-04), (float)(1.9993904238e+00) },	//	  20.0 Hz
	{ (float)(9.9940551149e-01), (float)(2.9724425274e-04), (float)(1.9993928282e+00) },	//	  25.0 Hz
	{ (float)(9.9925718616e-01), (float)(3.7140692231e-04), (float)(1.9992370516e+00) },	//	  31.5 Hz
	{ (float)(9.9879758671e-01), (float)(6.0120664727e-04), (float)(1.9987651273e+00) },	//	  40.0 Hz
	{ (float)(9.9849722245e-01), (float)(7.5138877401e-04), (float)(1.9984465124e+00) },	//	  50.0 Hz
	{ (float)(9.9820192714e-01), (float)(8.9903643123e-04), (float)(1.9981214319e+00) },	//	  63.0 Hz
	{ (float)(9.9759663784e-01), (float)(1.2016810790e-03), (float)(1.9974668794e+00) },	//	  80.0 Hz
	{ (float)(9.9699670283e-01), (float)(1.5016485839e-03), (float)(1.9967940174e+00) },	//   100.0 Hz
	{ (float)(9.9608832771e-01), (float)(1.9558361473e-03), (float)(1.9957717788e+00) },	//   125.0 Hz
	{ (float)(9.9488106021e-01), (float)(2.5594698955e-03), (float)(1.9943627488e+00) },	//   160.0 Hz
	{ (float)(9.9368508558e-01), (float)(3.1574572116e-03), (float)(1.9928757293e+00) },	//   200.0 Hz
	{ (float)(9.9187386982e-01), (float)(4.0630650882e-03), (float)(1.9906104476e+00) },	//   250.0 Hz
	{ (float)(9.8977837468e-01), (float)(5.1108126620e-03), (float)(1.9877748003e+00) },	//   315.0 Hz
	{ (float)(9.8709369779e-01), (float)(6.4531511061e-03), (float)(1.9838676311e+00) },	//   400.0 Hz
	{ (float)(9.8381454728e-01), (float)(8.0927263624e-03), (float)(1.9787829025e+00) },	//   500.0 Hz
	{ (float)(9.7966277109e-01), (float)(1.0168614455e-02), (float)(1.9716932308e+00) },	//   630.0 Hz
	{ (float)(9.7404386878e-01), (float)(1.2978065611e-02), (float)(1.9612347544e+00) },	//   800.0 Hz
	{ (float)(9.6758591875e-01), (float)(1.6207040627e-02), (float)(1.9476493009e+00) },	//  1000.0 Hz
	{ (float)(9.5973086514e-01), (float)(2.0134567431e-02), (float)(1.9287337831e+00) },	//  1250.0 Hz
	{ (float)(9.4878629133e-01), (float)(2.5606854334e-02), (float)(1.8983695001e+00) },	//  1600.0 Hz
	{ (float)(9.3627068388e-01), (float)(3.1864658062e-02), (float)(1.8581910087e+00) },	//  2000.0 Hz
	{ (float)(9.2117604381e-01), (float)(3.9411978094e-02), (float)(1.8005882747e+00) },	//  2500.0 Hz
	{ (float)(9.0172987031e-01), (float)(4.9135064847e-02), (float)(1.7133994083e+00) },	//  3150.0 Hz
	{ (float)(8.7697241507e-01), (float)(6.1513792463e-02), (float)(1.5803227133e+00) },	//  4000.0 Hz
	{ (float)(8.4900435915e-01), (float)(7.5497820425e-02), (float)(1.3993428287e+00) },	//  5000.0 Hz
	{ (float)(8.1426291228e-01), (float)(9.2868543858e-02), (float)(1.1311744237e+00) },	//  6300.0 Hz
	{ (float)(7.7194867684e-01), (float)(1.1402566158e-01), (float)(7.4026698287e-01) },	//  8000.0 Hz
	{ (float)(7.2627335006e-01), (float)(1.3686332497e-01), (float)(2.5120594308e-01) },	// 10000.0 Hz
	{ (float)(6.7690084582e-01), (float)(1.6154957709e-01), (float)(-3.4981568641e-01) },	// 12500.0 Hz
	{ (float)(6.2492532874e-01), (float)(1.8753733563e-01), (float)(-1.0577231561e+00) },	// 16000.0 Hz
	{ (float)(6.1776462189e-01), (float)(1.9111768906e-01), (float)(-1.5492495659e+00) },	// 20000.0 Hz
};

maEqualizerSettings g_EqualizerSettings;


void maEqualizerReset(int bands, int bits16, int extra)
{
	eq31Init(bands, bits16, extra);

} // maEqualizerReset

int nEQNum = 0;

int EQ2[2] = {	64,	64	};
int EQ3[3] = {	0,	64,	0	};
int EQ5[5] = {	0,	0,	64,	64,	0	};
int EQ10Up[10] = {	4,	10,	17,	23,	29,	36,	42,	49,	55, 61	};
int EQ10Down[10] = {	59,	53,	46,	40,	34,	27,	21,	14,	8, 2	};

double slidertodb[65] = {
-16.0, -15.5, -15.0, -14.5, -14.0, -13.5, -13.0, -12.5, -12.0, -11.5, -11.0, -10.5, -10.0,  -9.5, -9.0, -8.5,
 -8.0,  -7.5,  -7.0,  -6.5,  -6.0,  -5.5,  -5.0,  -4.5,  -4.0,  -3.5,  -3.0,  -2.5,  -2.0,  -1.5, -1.0, -0.5,
  0.0,   0.5,   1.0,   1.5,   2.0,   2.5,   3.0,   3.5,   4.0,   4.5,   5.0,   5.5,   6.0,   6.5,  7.0,  7.5,
  8.0,   8.5,   9.0,   9.5,  10.0,  10.5,  11.0,  11.5,  12.0,  12.5,  13.0,  13.5,  14.0,  14.5, 15.0, 15.5,
 16.0
};
double DBfromScaleGain(int value);
double DBfromScaleGain(int value)
{
/*
	if(value >= EQSLIDERMIN && value <= EQSLIDERMAX)
		return slidertodb[64];
	return 0.0;
*/
//	return slidertodb[EQ2[nEQNum]];
//	return slidertodb[EQ3[nEQNum]];
//	return slidertodb[EQ5[nEQNum]];
	return slidertodb[EQ10Up[nEQNum]];
//	return slidertodb[EQ10Down[nEQNum]];
}


void maEqualizerSetLevels(int bands31, int dboffset)
{
	int band;
	int numbands = bands31 ? EQBANDS31 : EQBANDS10;
	int slider0 = bands31 ? 0 : 2;
	int slider;
	int sliderincr = bands31 ? 1 : 3;
	int slideroffset;

	g_state.insamplerate = 44100;
	
	if(g_state.insamplerate > 39289) // || !(g_sets.eqflags & MAEQADAPTRATE))
	{
		for(band = 0; band < numbands; band++) // 44100, 48000
		{
			// slider value 0...64 -> range -16...+16 dB
			eq31EqualizerSetLevel(band, pow(10,(dboffset + DBfromScaleGain(g_EqualizerSettings.Levels[slider0])) / 20.0));
			slider0 += sliderincr;
			nEQNum++;
		}

		nEQNum = 0;
	}
	else
	{
		// adapt for samplerates < 44100 by 1 slider (1/3 octave) shifts
								// 8000 nominal sample rate
		if(g_state.insamplerate <= 9822)
			slideroffset = -7;			
								// 11025, 12000			
		else if(g_state.insamplerate <= 12375)
			slideroffset = -6;			
		else if(g_state.insamplerate <= 15592)
			slideroffset = -5;			
								// 16000			
		else if(g_state.insamplerate <= 19644)
			slideroffset = -4;			
								// 22050, 24000
		else if(g_state.insamplerate <= 24750)
			slideroffset = -3;			
		else if(g_state.insamplerate <= 31183)
			slideroffset = -2;			
								// 32000
		else slideroffset = -1; // <= 39289

		if((slider = slider0 + slideroffset) < slider0)
			slider = slider0;

		for(band = 0; band < numbands; band++)
		{
			eq31EqualizerSetLevel(band, pow(10,(dboffset + DBfromScaleGain(g_EqualizerSettings.Levels[slider])) / 20.0));

			slideroffset += sliderincr;
			if((slider = slider0 + slideroffset) < slider0)
				slider = slider0;