channelmap.c

/*
 * Copyright 2011-2013 Various Authors
 * Copyright 2011 Johannes Weißl
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include "channelmap.h"
#include "utils.h"

void channel_map_init_waveex(int channels, unsigned int mask, channel_position_t *map)
{
	/* http://www.microsoft.com/whdc/device/audio/multichaud.mspx#EMLAC */
	const channel_position_t channel_map_waveex[] = {
		CHANNEL_POSITION_FRONT_LEFT,
		CHANNEL_POSITION_FRONT_RIGHT,
		CHANNEL_POSITION_FRONT_CENTER,
		CHANNEL_POSITION_LFE,
		CHANNEL_POSITION_REAR_LEFT,
		CHANNEL_POSITION_REAR_RIGHT,
		CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
		CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
		CHANNEL_POSITION_REAR_CENTER,
		CHANNEL_POSITION_SIDE_LEFT,
		CHANNEL_POSITION_SIDE_RIGHT,
		CHANNEL_POSITION_TOP_CENTER,
		CHANNEL_POSITION_TOP_FRONT_LEFT,
		CHANNEL_POSITION_TOP_FRONT_CENTER,
		CHANNEL_POSITION_TOP_FRONT_RIGHT,
		CHANNEL_POSITION_TOP_REAR_LEFT,
		CHANNEL_POSITION_TOP_REAR_CENTER,
		CHANNEL_POSITION_TOP_REAR_RIGHT
	};

	if (channels == 1) {
		map[0] = CHANNEL_POSITION_MONO;
	} else if (channels > 1 && channels < N_ELEMENTS(channel_map_waveex)) {
		int i, j = 0;

		if (!mask)
			mask = (1 << channels) - 1;

		for (i = 0; i < N_ELEMENTS(channel_map_waveex); i++) {
			if (mask & (1 << i))
				map[j++] = channel_map_waveex[i];
		}
		if (j != channels)
			map[0] = CHANNEL_POSITION_INVALID;
	} else {
		map[0] = CHANNEL_POSITION_INVALID;
	}
}