mpd/src/ReplayGainInfo.cxx

/*
 * Copyright 2003-2020 The Music Player Daemon Project
 * http://www.musicpd.org
 *
 * 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 "ReplayGainInfo.hxx"
#include "ReplayGainConfig.hxx"

#include <math.h>

float
ReplayGainTuple::CalculateScale(const ReplayGainConfig &config) const noexcept
{
	float scale;

	if (IsDefined()) {
		scale = pow(10.0, gain / 20.0);
		scale *= config.preamp;
		if (scale > 15.0)
			scale = 15.0;

		if (config.limit && scale * peak > 1.0)
			scale = 1.0 / peak;
	} else
		scale = config.missing_preamp;

	return scale;
}