Mercurial > hg > svcore
view base/AudioLevel.h @ 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 | d397ea0a79f5 |
children | cc27f35aa75c |
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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. */ #ifndef _AUDIO_LEVEL_H_ #define _AUDIO_LEVEL_H_ /** * AudioLevel converts audio sample levels between various scales: * * - dB values (-inf -> 0dB) * - floating-point values (-1.0 -> 1.0) such as used for a * multiplier for gain or in floating-point WAV files * - integer values intended to correspond to pixels on a fader * or vu level scale. */ 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