volume.c


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/*
    DeaDBeeF - ultimate music player for GNU/Linux systems with X11
    Copyright (C) 2009  Alexey Yakovenko

    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.
    
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/
#include <math.h>
#include <stdio.h>
#include "volume.h"

static float volume_db = 0; // in dB
static float volume_amp = 1; // amplitude [0..1]

void
volume_set_db (float dB) {
    volume_db = dB;
    volume_amp = dB > -60 ? db_to_amp (dB) : 0;
}

float
volume_get_db (void) {
    return volume_db;
}

void
volume_set_amp (float amp) {
    volume_amp = amp;
    volume_db = amp > 0 ? amp_to_db (amp) : -60.f;
}

float
volume_get_amp (void) {
    return volume_amp;
}

float
db_to_amp (float dB) {
    return pow (10, dB/20.f);
}

float
amp_to_db (float amp) {
    return 20*log10 (amp);
}