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66 lines
2.0 KiB
66 lines
2.0 KiB
/*
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Rosegarden
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A sequencer and musical notation editor.
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This program is Copyright 2000-2008
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Guillaume Laurent <glaurent@telegraph-road.org>,
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Chris Cannam <cannam@all-day-breakfast.com>,
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Richard Bown <bownie@bownie.com>
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The moral right of the authors to claim authorship of this work
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has been asserted.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version. See the file
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COPYING included with this distribution for more information.
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*/
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#ifndef _AUDIO_LEVEL_H_
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#define _AUDIO_LEVEL_H_
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namespace Rosegarden {
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/**
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* We need to represent audio levels in three different ways: as dB
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* values; as a floating-point multiplier for gain; and as an integer
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* on a scale for fader position and vu level. This class does the
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* necessary conversions.
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*/
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class AudioLevel
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{
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public:
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static const float DB_FLOOR;
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enum FaderType {
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ShortFader = 0, // -40 -> +6 dB
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LongFader = 1, // -70 -> +10 dB
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IEC268Meter = 2, // -70 -> 0 dB
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IEC268LongMeter = 3, // -70 -> +10 dB (0dB aligns with LongFader)
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PreviewLevel = 4
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};
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static float multiplier_to_dB(float multiplier);
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static float dB_to_multiplier(float dB);
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static float fader_to_dB(int level, int maxLevel, FaderType type);
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static int dB_to_fader(float dB, int maxFaderLevel, FaderType type);
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static float fader_to_multiplier(int level, int maxLevel, FaderType type);
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static int multiplier_to_fader(float multiplier, int maxFaderLevel,
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FaderType type);
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// fast if "levels" doesn't change often -- for audio segment previews
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static int multiplier_to_preview(float multiplier, int levels);
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static float preview_to_multiplier(int level, int levels);
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};
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}
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#endif
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