Mercurial > hg > svcore
view base/AudioLevel.cpp @ 1114:e80abd659922 3.0-integration
Merge from default branch
author | Chris Cannam |
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date | Tue, 07 Jul 2015 17:39:06 +0100 |
parents | cc27f35aa75c |
children | 48e9f538e6e9 |
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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */ /* Sonic Visualiser An audio file viewer and annotation editor. Centre for Digital Music, Queen Mary, University of London. 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. See the file COPYING included with this distribution for more information. */ /* This is a modified version of a source file from the Rosegarden MIDI and audio sequencer and notation editor. This file copyright 2000-2006 Chris Cannam. */ #include "AudioLevel.h" #include <cmath> #include <iostream> #include <map> #include <vector> #include <cassert> #include "system/System.h" const double AudioLevel::DB_FLOOR = -1000.; struct FaderDescription { FaderDescription(double _minDb, double _maxDb, double _zeroPoint) : minDb(_minDb), maxDb(_maxDb), zeroPoint(_zeroPoint) { } double minDb; double maxDb; double zeroPoint; // as fraction of total throw }; static const FaderDescription faderTypes[] = { FaderDescription(-40., +6., 0.75), // short FaderDescription(-70., +10., 0.80), // long FaderDescription(-70., 0., 1.00), // IEC268 FaderDescription(-70., +10., 0.80), // IEC268 long FaderDescription(-40., 0., 1.00), // preview }; //typedef std::vector<double> LevelList; //static std::map<int, LevelList> previewLevelCache; //static const LevelList &getPreviewLevelCache(int levels); double AudioLevel::multiplier_to_dB(double multiplier) { if (multiplier == 0.) return DB_FLOOR; else if (multiplier < 0.) return multiplier_to_dB(-multiplier); double dB = 10 * log10(multiplier); return dB; } double AudioLevel::dB_to_multiplier(double dB) { if (dB == DB_FLOOR) return 0.; double m = pow(10., dB / 10.); return m; } /* IEC 60-268-18 fader levels. Thanks to Steve Harris. */ static double iec_dB_to_fader(double db) { double def = 0.0f; // Meter deflection %age if (db < -70.0f) { def = 0.0f; } else if (db < -60.0f) { def = (db + 70.0f) * 0.25f; } else if (db < -50.0f) { def = (db + 60.0f) * 0.5f + 2.5f; // corrected from 5.0f base, thanks Robin Gareus } else if (db < -40.0f) { def = (db + 50.0f) * 0.75f + 7.5f; } else if (db < -30.0f) { def = (db + 40.0f) * 1.5f + 15.0f; } else if (db < -20.0f) { def = (db + 30.0f) * 2.0f + 30.0f; } else { def = (db + 20.0f) * 2.5f + 50.0f; } return def; } static double iec_fader_to_dB(double def) // Meter deflection %age { double db = 0.0f; if (def >= 50.0f) { db = (def - 50.0f) / 2.5f - 20.0f; } else if (def >= 30.0f) { db = (def - 30.0f) / 2.0f - 30.0f; } else if (def >= 15.0f) { db = (def - 15.0f) / 1.5f - 40.0f; } else if (def >= 7.5f) { db = (def - 7.5f) / 0.75f - 50.0f; } else if (def >= 2.5f) { db = (def - 2.5f) / 0.5f - 60.0f; } else { db = (def / 0.25f) - 70.0f; } return db; } double AudioLevel::fader_to_dB(int level, int maxLevel, FaderType type) { if (level == 0) return DB_FLOOR; if (type == IEC268Meter || type == IEC268LongMeter) { double maxPercent = iec_dB_to_fader(faderTypes[type].maxDb); double percent = double(level) * maxPercent / double(maxLevel); double dB = iec_fader_to_dB(percent); return dB; } else { // scale proportional to sqrt(fabs(dB)) int zeroLevel = int(maxLevel * faderTypes[type].zeroPoint); if (level >= zeroLevel) { double value = level - zeroLevel; double scale = (maxLevel - zeroLevel) / sqrt(faderTypes[type].maxDb); value /= scale; double dB = pow(value, 2.); return dB; } else { double value = zeroLevel - level; double scale = zeroLevel / sqrt(0. - faderTypes[type].minDb); value /= scale; double dB = pow(value, 2.); return 0. - dB; } } } int AudioLevel::dB_to_fader(double dB, int maxLevel, FaderType type) { if (dB == DB_FLOOR) return 0; if (type == IEC268Meter || type == IEC268LongMeter) { // The IEC scale gives a "percentage travel" for a given dB // level, but it reaches 100% at 0dB. So we want to treat the // result not as a percentage, but as a scale between 0 and // whatever the "percentage" for our (possibly >0dB) max dB is. double maxPercent = iec_dB_to_fader(faderTypes[type].maxDb); double percent = iec_dB_to_fader(dB); int faderLevel = int((maxLevel * percent) / maxPercent + 0.01f); if (faderLevel < 0) faderLevel = 0; if (faderLevel > maxLevel) faderLevel = maxLevel; return faderLevel; } else { int zeroLevel = int(maxLevel * faderTypes[type].zeroPoint); if (dB >= 0.) { if (faderTypes[type].maxDb <= 0.) { return maxLevel; } else { double value = sqrt(dB); double scale = (maxLevel - zeroLevel) / sqrt(faderTypes[type].maxDb); value *= scale; int level = int(value + 0.01f) + zeroLevel; if (level > maxLevel) level = maxLevel; return level; } } else { dB = 0. - dB; double value = sqrt(dB); double scale = zeroLevel / sqrt(0. - faderTypes[type].minDb); value *= scale; int level = zeroLevel - int(value + 0.01f); if (level < 0) level = 0; return level; } } } double AudioLevel::fader_to_multiplier(int level, int maxLevel, FaderType type) { if (level == 0) return 0.; return dB_to_multiplier(fader_to_dB(level, maxLevel, type)); } int AudioLevel::multiplier_to_fader(double multiplier, int maxLevel, FaderType type) { if (multiplier == 0.) return 0; double dB = multiplier_to_dB(multiplier); int fader = dB_to_fader(dB, maxLevel, type); return fader; } /* const LevelList & getPreviewLevelCache(int levels) { LevelList &ll = previewLevelCache[levels]; if (ll.empty()) { for (int i = 0; i <= levels; ++i) { double m = AudioLevel::fader_to_multiplier (i + levels/4, levels + levels/4, AudioLevel::PreviewLevel); if (levels == 1) m /= 100; // noise ll.push_back(m); } } return ll; } */ int AudioLevel::multiplier_to_preview(double m, int levels) { assert(levels > 0); return multiplier_to_fader(m, levels, PreviewLevel); /* The original multiplier_to_preview which follows is not thread-safe. if (m < 0.) return -multiplier_to_preview(-m, levels); const LevelList &ll = getPreviewLevelCache(levels); int result = -1; int lo = 0, hi = levels; // binary search int level = -1; while (result < 0) { int newlevel = (lo + hi) / 2; if (newlevel == level || newlevel == 0 || newlevel == levels) { result = newlevel; break; } level = newlevel; if (ll[level] >= m) { hi = level; } else if (ll[level+1] >= m) { result = level; } else { lo = level; } } return result; */ } double AudioLevel::preview_to_multiplier(int level, int levels) { assert(levels > 0); return fader_to_multiplier(level, levels, PreviewLevel); /* if (level < 0) return -preview_to_multiplier(-level, levels); const LevelList &ll = getPreviewLevelCache(levels); return ll[level]; */ }