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// -*- c-basic-offset: 4 -*-
/*
Rosegarden
A sequencer and musical notation editor.
This program is Copyright 2000-2008
Guillaume Laurent <glaurent@telegraph-road.org>,
Chris Cannam <cannam@all-day-breakfast.com>,
Richard Bown <bownie@bownie.com>
The moral right of the authors to claim authorship of this work
has been asserted.
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.
*/
#ifndef _AUDIO_LEVEL_H_
#define _AUDIO_LEVEL_H_
namespace Rosegarden {
/**
* We need to represent audio levels in three different ways: as dB
* values; as a floating-point multiplier for gain; and as an integer
* on a scale for fader position and vu level. This class does the
* necessary conversions.
*/
class AudioLevel
{
public:
static const float DB_FLOOR;
enum FaderType {
ShortFader = 0, // -40 -> +6 dB
LongFader = 1, // -70 -> +10 dB
IEC268Meter = 2, // -70 -> 0 dB
IEC268LongMeter = 3, // -70 -> +10 dB (0dB aligns with LongFader)
PreviewLevel = 4
};
static float multiplier_to_dB(float multiplier);
static float dB_to_multiplier(float dB);
static float fader_to_dB(int level, int maxLevel, FaderType type);
static int dB_to_fader(float dB, int maxFaderLevel, FaderType type);
static float fader_to_multiplier(int level, int maxLevel, FaderType type);
static int multiplier_to_fader(float multiplier, int maxFaderLevel,
FaderType type);
// fast if "levels" doesn't change often -- for audio segment previews
static int multiplier_to_preview(float multiplier, int levels);
static float preview_to_multiplier(int level, int levels);
};
}
#endif
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