annotate base/AudioLevel.h @ 1886:f803d3c33f76 tip

Switch off copious debug in soft synth driving
author Chris Cannam
date Fri, 14 Aug 2020 10:44:44 +0100
parents ad5f892c0c4d
children
rev   line source
Chris@49 1 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
Chris@0 2
Chris@0 3 /*
Chris@52 4 Sonic Visualiser
Chris@52 5 An audio file viewer and annotation editor.
Chris@52 6 Centre for Digital Music, Queen Mary, University of London.
Chris@0 7
Chris@52 8 This program is free software; you can redistribute it and/or
Chris@52 9 modify it under the terms of the GNU General Public License as
Chris@52 10 published by the Free Software Foundation; either version 2 of the
Chris@52 11 License, or (at your option) any later version. See the file
Chris@52 12 COPYING included with this distribution for more information.
Chris@0 13 */
Chris@0 14
Chris@0 15 /*
Chris@0 16 This is a modified version of a source file from the
Chris@0 17 Rosegarden MIDI and audio sequencer and notation editor.
Chris@17 18 This file copyright 2000-2006 Chris Cannam.
Chris@0 19 */
Chris@0 20
Chris@1581 21 #ifndef SV_AUDIO_LEVEL_H
Chris@1581 22 #define SV_AUDIO_LEVEL_H
Chris@0 23
Chris@0 24 /**
Chris@0 25 * AudioLevel converts audio sample levels between various scales:
Chris@0 26 *
Chris@0 27 * - dB values (-inf -> 0dB)
Chris@0 28 * - floating-point values (-1.0 -> 1.0) such as used for a
Chris@0 29 * multiplier for gain or in floating-point WAV files
Chris@0 30 * - integer values intended to correspond to pixels on a fader
Chris@0 31 * or vu level scale.
Chris@0 32 */
Chris@0 33
Chris@0 34 class AudioLevel
Chris@0 35 {
Chris@0 36 public:
Chris@0 37
Chris@1038 38 static const double DB_FLOOR;
Chris@0 39
Chris@0 40 enum FaderType {
Chris@1429 41 ShortFader = 0, // -40 -> +6 dB
Chris@0 42 LongFader = 1, // -70 -> +10 dB
Chris@0 43 IEC268Meter = 2, // -70 -> 0 dB
Chris@0 44 IEC268LongMeter = 3, // -70 -> +10 dB (0dB aligns with LongFader)
Chris@1429 45 PreviewLevel = 4
Chris@0 46 };
Chris@0 47
Chris@1038 48 static double multiplier_to_dB(double multiplier);
Chris@1038 49 static double dB_to_multiplier(double dB);
Chris@0 50
Chris@1038 51 static double fader_to_dB(int level, int maxLevel, FaderType type);
Chris@1038 52 static int dB_to_fader(double dB, int maxFaderLevel, FaderType type);
Chris@0 53
Chris@1038 54 static double fader_to_multiplier(int level, int maxLevel, FaderType type);
Chris@1038 55 static int multiplier_to_fader(double multiplier, int maxFaderLevel,
Chris@1429 56 FaderType type);
Chris@0 57
Chris@0 58 // fast if "levels" doesn't change often -- for audio segment previews
Chris@1038 59 static int multiplier_to_preview(double multiplier, int levels);
Chris@1038 60 static double preview_to_multiplier(int level, int levels);
Chris@0 61 };
Chris@0 62
Chris@0 63
Chris@0 64 #endif
Chris@0 65