Chris@49: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@0: 
Chris@0: /*
Chris@52:     Sonic Visualiser
Chris@52:     An audio file viewer and annotation editor.
Chris@52:     Centre for Digital Music, Queen Mary, University of London.
Chris@0:     
Chris@52:     This program is free software; you can redistribute it and/or
Chris@52:     modify it under the terms of the GNU General Public License as
Chris@52:     published by the Free Software Foundation; either version 2 of the
Chris@52:     License, or (at your option) any later version.  See the file
Chris@52:     COPYING included with this distribution for more information.
Chris@0: */
Chris@0: 
Chris@0: /*
Chris@0:    This is a modified version of a source file from the 
Chris@0:    Rosegarden MIDI and audio sequencer and notation editor.
Chris@17:    This file copyright 2000-2006 Chris Cannam.
Chris@0: */
Chris@0: 
Chris@150: #include "AudioLevel.h"
Chris@0: #include <cmath>
Chris@0: #include <iostream>
Chris@0: #include <map>
Chris@0: #include <vector>
Chris@0: #include <cassert>
Chris@0: 
Chris@240: const float AudioLevel::DB_FLOOR = -1000.f;
Chris@0: 
Chris@0: struct FaderDescription
Chris@0: {
Chris@0:     FaderDescription(float _minDb, float _maxDb, float _zeroPoint) :
Chris@0: 	minDb(_minDb), maxDb(_maxDb), zeroPoint(_zeroPoint) { }
Chris@0: 
Chris@0:     float minDb;
Chris@0:     float maxDb;
Chris@0:     float zeroPoint; // as fraction of total throw
Chris@0: };
Chris@0: 
Chris@0: static const FaderDescription faderTypes[] = {
Chris@240:     FaderDescription(-40.f,  +6.f, 0.75f), // short
Chris@240:     FaderDescription(-70.f, +10.f, 0.80f), // long
Chris@240:     FaderDescription(-70.f,   0.f, 1.00f), // IEC268
Chris@240:     FaderDescription(-70.f, +10.f, 0.80f), // IEC268 long
Chris@240:     FaderDescription(-40.f,   0.f, 1.00f), // preview
Chris@0: };
Chris@0: 
Chris@0: typedef std::vector<float> LevelList;
Chris@0: static std::map<int, LevelList> previewLevelCache;
Chris@0: static const LevelList &getPreviewLevelCache(int levels);
Chris@0: 
Chris@0: float
Chris@0: AudioLevel::multiplier_to_dB(float multiplier)
Chris@0: {
Chris@234:     if (multiplier == 0.f) return DB_FLOOR;
Chris@234:     else if (multiplier < 0.f) return multiplier_to_dB(-multiplier);
Chris@0:     float dB = 10 * log10f(multiplier);
Chris@0:     return dB;
Chris@0: }
Chris@0: 
Chris@0: float
Chris@0: AudioLevel::dB_to_multiplier(float dB)
Chris@0: {
Chris@240:     if (dB == DB_FLOOR) return 0.f;
Chris@240:     float m = powf(10.f, dB / 10.f);
Chris@0:     return m;
Chris@0: }
Chris@0: 
Chris@0: /* IEC 60-268-18 fader levels.  Thanks to Steve Harris. */
Chris@0: 
Chris@0: static float iec_dB_to_fader(float db)
Chris@0: {
Chris@0:     float def = 0.0f; // Meter deflection %age
Chris@0: 
Chris@0:     if (db < -70.0f) {
Chris@0:         def = 0.0f;
Chris@0:     } else if (db < -60.0f) {
Chris@0:         def = (db + 70.0f) * 0.25f;
Chris@0:     } else if (db < -50.0f) {
Chris@0:         def = (db + 60.0f) * 0.5f + 5.0f;
Chris@0:     } else if (db < -40.0f) {
Chris@0:         def = (db + 50.0f) * 0.75f + 7.5f;
Chris@0:     } else if (db < -30.0f) {
Chris@0:         def = (db + 40.0f) * 1.5f + 15.0f;
Chris@0:     } else if (db < -20.0f) {
Chris@0:         def = (db + 30.0f) * 2.0f + 30.0f;
Chris@0:     } else {
Chris@0:         def = (db + 20.0f) * 2.5f + 50.0f;
Chris@0:     }
Chris@0: 
Chris@0:     return def;
Chris@0: }
Chris@0: 
Chris@0: static float iec_fader_to_dB(float def)  // Meter deflection %age
Chris@0: {
Chris@0:     float db = 0.0f;
Chris@0: 
Chris@0:     if (def >= 50.0f) {
Chris@0: 	db = (def - 50.0f) / 2.5f - 20.0f;
Chris@0:     } else if (def >= 30.0f) {
Chris@0: 	db = (def - 30.0f) / 2.0f - 30.0f;
Chris@0:     } else if (def >= 15.0f) {
Chris@0: 	db = (def - 15.0f) / 1.5f - 40.0f;
Chris@0:     } else if (def >= 7.5f) {
Chris@0: 	db = (def - 7.5f) / 0.75f - 50.0f;
Chris@0:     } else if (def >= 5.0f) {
Chris@0: 	db = (def - 5.0f) / 0.5f - 60.0f;
Chris@0:     } else {
Chris@0: 	db = (def / 0.25f) - 70.0f;
Chris@0:     }
Chris@0: 
Chris@0:     return db;
Chris@0: }
Chris@0: 
Chris@0: float
Chris@0: AudioLevel::fader_to_dB(int level, int maxLevel, FaderType type)
Chris@0: {
Chris@0:     if (level == 0) return DB_FLOOR;
Chris@0: 
Chris@0:     if (type == IEC268Meter || type == IEC268LongMeter) {
Chris@0: 
Chris@0: 	float maxPercent = iec_dB_to_fader(faderTypes[type].maxDb);
Chris@0: 	float percent = float(level) * maxPercent / float(maxLevel);
Chris@0: 	float dB = iec_fader_to_dB(percent);
Chris@0: 	return dB;
Chris@0: 
Chris@0:     } else { // scale proportional to sqrt(fabs(dB))
Chris@0: 
Chris@0: 	int zeroLevel = int(maxLevel * faderTypes[type].zeroPoint);
Chris@0:     
Chris@0: 	if (level >= zeroLevel) {
Chris@0: 	    
Chris@0: 	    float value = level - zeroLevel;
Chris@0: 	    float scale = float(maxLevel - zeroLevel) /
Chris@0: 		sqrtf(faderTypes[type].maxDb);
Chris@0: 	    value /= scale;
Chris@240: 	    float dB = powf(value, 2.f);
Chris@0: 	    return dB;
Chris@0: 	    
Chris@0: 	} else {
Chris@0: 	    
Chris@0: 	    float value = zeroLevel - level;
Chris@240: 	    float scale = zeroLevel / sqrtf(0.f - faderTypes[type].minDb);
Chris@0: 	    value /= scale;
Chris@240: 	    float dB = powf(value, 2.f);
Chris@240: 	    return 0.f - dB;
Chris@0: 	}
Chris@0:     }
Chris@0: }
Chris@0: 
Chris@0: 
Chris@0: int
Chris@0: AudioLevel::dB_to_fader(float dB, int maxLevel, FaderType type)
Chris@0: {
Chris@0:     if (dB == DB_FLOOR) return 0;
Chris@0: 
Chris@0:     if (type == IEC268Meter || type == IEC268LongMeter) {
Chris@0: 
Chris@0: 	// The IEC scale gives a "percentage travel" for a given dB
Chris@0: 	// level, but it reaches 100% at 0dB.  So we want to treat the
Chris@0: 	// result not as a percentage, but as a scale between 0 and
Chris@0: 	// whatever the "percentage" for our (possibly >0dB) max dB is.
Chris@0: 	
Chris@0: 	float maxPercent = iec_dB_to_fader(faderTypes[type].maxDb);
Chris@0: 	float percent = iec_dB_to_fader(dB);
Chris@240: 	int faderLevel = int((maxLevel * percent) / maxPercent + 0.01f);
Chris@0: 	
Chris@0: 	if (faderLevel < 0) faderLevel = 0;
Chris@0: 	if (faderLevel > maxLevel) faderLevel = maxLevel;
Chris@0: 	return faderLevel;
Chris@0: 
Chris@0:     } else {
Chris@0: 
Chris@0: 	int zeroLevel = int(maxLevel * faderTypes[type].zeroPoint);
Chris@0: 
Chris@240: 	if (dB >= 0.f) {
Chris@0: 	    
Chris@240:             if (faderTypes[type].maxDb <= 0.f) {
Chris@240:                 
Chris@240:                 return maxLevel;
Chris@240: 
Chris@240:             } else {
Chris@240: 
Chris@240:                 float value = sqrtf(dB);
Chris@240:                 float scale = (maxLevel - zeroLevel) / sqrtf(faderTypes[type].maxDb);
Chris@240:                 value *= scale;
Chris@240:                 int level = int(value + 0.01f) + zeroLevel;
Chris@240:                 if (level > maxLevel) level = maxLevel;
Chris@240:                 return level;
Chris@240:             }
Chris@0: 	    
Chris@0: 	} else {
Chris@0: 
Chris@240: 	    dB = 0.f - dB;
Chris@0: 	    float value = sqrtf(dB);
Chris@240: 	    float scale = zeroLevel / sqrtf(0.f - faderTypes[type].minDb);
Chris@0: 	    value *= scale;
Chris@240: 	    int level = zeroLevel - int(value + 0.01f);
Chris@0: 	    if (level < 0) level = 0;
Chris@0: 	    return level;
Chris@0: 	}
Chris@0:     }
Chris@0: }
Chris@0: 
Chris@0: 	
Chris@0: float
Chris@0: AudioLevel::fader_to_multiplier(int level, int maxLevel, FaderType type)
Chris@0: {
Chris@240:     if (level == 0) return 0.f;
Chris@0:     return dB_to_multiplier(fader_to_dB(level, maxLevel, type));
Chris@0: }
Chris@0: 
Chris@0: int
Chris@0: AudioLevel::multiplier_to_fader(float multiplier, int maxLevel, FaderType type)
Chris@0: {
Chris@240:     if (multiplier == 0.f) return 0;
Chris@0:     float dB = multiplier_to_dB(multiplier);
Chris@0:     int fader = dB_to_fader(dB, maxLevel, type);
Chris@0:     return fader;
Chris@0: }
Chris@0: 
Chris@0: 
Chris@0: const LevelList &
Chris@0: getPreviewLevelCache(int levels)
Chris@0: {
Chris@0:     LevelList &ll = previewLevelCache[levels];
Chris@0:     if (ll.empty()) {
Chris@0: 	for (int i = 0; i <= levels; ++i) {
Chris@0: 	    float m = AudioLevel::fader_to_multiplier
Chris@0: 		(i + levels/4, levels + levels/4, AudioLevel::PreviewLevel);
Chris@0: 	    if (levels == 1) m /= 100; // noise
Chris@0: 	    ll.push_back(m);
Chris@0: 	}
Chris@0:     }
Chris@0:     return ll;
Chris@0: }
Chris@0: 
Chris@0: int
Chris@0: AudioLevel::multiplier_to_preview(float m, int levels)
Chris@0: {
Chris@0:     assert(levels > 0);
Chris@234:     return multiplier_to_fader(m, levels, PreviewLevel);
Chris@234: 
Chris@234:     /* The original multiplier_to_preview which follows is not thread-safe.
Chris@234: 
Chris@240:     if (m < 0.f) return -multiplier_to_preview(-m, levels);
Chris@0: 
Chris@0:     const LevelList &ll = getPreviewLevelCache(levels);
Chris@0:     int result = -1;
Chris@0: 
Chris@0:     int lo = 0, hi = levels;
Chris@0: 
Chris@0:     // binary search
Chris@0:     int level = -1;
Chris@0:     while (result < 0) {
Chris@0: 	int newlevel = (lo + hi) / 2;
Chris@0: 	if (newlevel == level ||
Chris@0: 	    newlevel == 0 ||
Chris@0: 	    newlevel == levels) {
Chris@0: 	    result = newlevel;
Chris@0: 	    break;
Chris@0: 	}
Chris@0: 	level = newlevel;
Chris@0: 	if (ll[level] >= m) {
Chris@0: 	    hi = level;
Chris@0: 	} else if (ll[level+1] >= m) {
Chris@0: 	    result = level;
Chris@0: 	} else {
Chris@0: 	    lo = level;
Chris@0: 	}
Chris@0:     }
Chris@0: 		   
Chris@0:     return result;
Chris@234: 
Chris@234:     */
Chris@0: }
Chris@0: 
Chris@0: float
Chris@0: AudioLevel::preview_to_multiplier(int level, int levels)
Chris@0: {
Chris@0:     assert(levels > 0);
Chris@234:     return fader_to_multiplier(level, levels, PreviewLevel);
Chris@234: /*
Chris@0:     if (level < 0) return -preview_to_multiplier(-level, levels);
Chris@0:     const LevelList &ll = getPreviewLevelCache(levels);
Chris@0:     return ll[level];
Chris@234: */
Chris@0: }
Chris@0: 	
Chris@0: