Mercurial > hg > svcore
view base/AudioLevel.cpp @ 335:02d2ad95ea52 spectrogram-cache-rejig
* Get storage advice for each cache in an FFT data server. Allows us to be
more confident about the actual memory situation and cut over from memory
to disc part way through an FFT calculation if necessary. StorageAdviser
is now a bit too optimistic though (it's too keen to allocate large numbers
of small blocks in memory).
author | Chris Cannam |
---|---|
date | Tue, 13 Nov 2007 13:54:10 +0000 |
parents | dc46851837d6 |
children | bdc9bb371a9f |
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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> const float AudioLevel::DB_FLOOR = -1000.f; struct FaderDescription { FaderDescription(float _minDb, float _maxDb, float _zeroPoint) : minDb(_minDb), maxDb(_maxDb), zeroPoint(_zeroPoint) { } float minDb; float maxDb; float zeroPoint; // as fraction of total throw }; static const FaderDescription faderTypes[] = { FaderDescription(-40.f, +6.f, 0.75f), // short FaderDescription(-70.f, +10.f, 0.80f), // long FaderDescription(-70.f, 0.f, 1.00f), // IEC268 FaderDescription(-70.f, +10.f, 0.80f), // IEC268 long FaderDescription(-40.f, 0.f, 1.00f), // preview }; //typedef std::vector<float> LevelList; //static std::map<int, LevelList> previewLevelCache; //static const LevelList &getPreviewLevelCache(int levels); float AudioLevel::multiplier_to_dB(float multiplier) { if (multiplier == 0.f) return DB_FLOOR; else if (multiplier < 0.f) return multiplier_to_dB(-multiplier); float dB = 10 * log10f(multiplier); return dB; } float AudioLevel::dB_to_multiplier(float dB) { if (dB == DB_FLOOR) return 0.f; float m = powf(10.f, dB / 10.f); return m; } /* IEC 60-268-18 fader levels. Thanks to Steve Harris. */ static float iec_dB_to_fader(float db) { float 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 + 5.0f; } 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 float iec_fader_to_dB(float def) // Meter deflection %age { float 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 >= 5.0f) { db = (def - 5.0f) / 0.5f - 60.0f; } else { db = (def / 0.25f) - 70.0f; } return db; } float AudioLevel::fader_to_dB(int level, int maxLevel, FaderType type) { if (level == 0) return DB_FLOOR; if (type == IEC268Meter || type == IEC268LongMeter) { float maxPercent = iec_dB_to_fader(faderTypes[type].maxDb); float percent = float(level) * maxPercent / float(maxLevel); float 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) { float value = level - zeroLevel; float scale = float(maxLevel - zeroLevel) / sqrtf(faderTypes[type].maxDb); value /= scale; float dB = powf(value, 2.f); return dB; } else { float value = zeroLevel - level; float scale = zeroLevel / sqrtf(0.f - faderTypes[type].minDb); value /= scale; float dB = powf(value, 2.f); return 0.f - dB; } } } int AudioLevel::dB_to_fader(float 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. float maxPercent = iec_dB_to_fader(faderTypes[type].maxDb); float 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.f) { if (faderTypes[type].maxDb <= 0.f) { return maxLevel; } else { float value = sqrtf(dB); float scale = (maxLevel - zeroLevel) / sqrtf(faderTypes[type].maxDb); value *= scale; int level = int(value + 0.01f) + zeroLevel; if (level > maxLevel) level = maxLevel; return level; } } else { dB = 0.f - dB; float value = sqrtf(dB); float scale = zeroLevel / sqrtf(0.f - faderTypes[type].minDb); value *= scale; int level = zeroLevel - int(value + 0.01f); if (level < 0) level = 0; return level; } } } float AudioLevel::fader_to_multiplier(int level, int maxLevel, FaderType type) { if (level == 0) return 0.f; return dB_to_multiplier(fader_to_dB(level, maxLevel, type)); } int AudioLevel::multiplier_to_fader(float multiplier, int maxLevel, FaderType type) { if (multiplier == 0.f) return 0; float 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) { float 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(float 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.f) 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; */ } float 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]; */ }