mpd/src/replay_gain_info.c

/*
 * Copyright (C) 2003-2011 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 "config.h"
#include "replay_gain_info.h"

float
replay_gain_tuple_scale(const struct replay_gain_tuple *tuple, float preamp, float missing_preamp, bool peak_limit)
{
	float scale;

	if (replay_gain_tuple_defined(tuple)) {
		scale = pow(10.0, tuple->gain / 20.0);
		scale *= preamp;
		if (scale > 15.0)
			scale = 15.0;

		if (peak_limit && scale * tuple->peak > 1.0)
			scale = 1.0 / tuple->peak;
	} else
		scale = missing_preamp;

	return scale;
}

void
replay_gain_info_complete(struct replay_gain_info *info)
{
	if (!replay_gain_tuple_defined(&info->tuples[REPLAY_GAIN_ALBUM]))
		info->tuples[REPLAY_GAIN_ALBUM] =
			info->tuples[REPLAY_GAIN_TRACK];
}