downmix.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.7平台上编译为嵌入式图形界面操作系统。

/*
 * downmix.c
 * Copyright (C) 2000-2002 Michel Lespinasse <[e-mail]>
 * Copyright (C) 1999-2000 Aaron Holtzman <[e-mail]>
 *
 * This file is part of a52dec, a free ATSC A-52 stream decoder.
 * See http://liba52.sourceforge.net/ for updates.
 *
 * a52dec 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.
 *
 * a52dec 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "a52.h"
#include "a52_internal.h"

#define CONVERT(acmod,output) (((output) << 3) + (acmod))

int a52_downmix_init (int input, int flags, sample_t * level,
		      sample_t clev, sample_t slev)
{
    static uint8_t table[11][8] = {
	{A52_CHANNEL,	A52_DOLBY,	A52_STEREO,	A52_STEREO,
	 A52_STEREO,	A52_STEREO,	A52_STEREO,	A52_STEREO},
	{A52_MONO,	A52_MONO,	A52_MONO,	A52_MONO,
	 A52_MONO,	A52_MONO,	A52_MONO,	A52_MONO},
	{A52_CHANNEL,	A52_DOLBY,	A52_STEREO,	A52_STEREO,
	 A52_STEREO,	A52_STEREO,	A52_STEREO,	A52_STEREO},
	{A52_CHANNEL,	A52_DOLBY,	A52_STEREO,	A52_3F,
	 A52_STEREO,	A52_3F,		A52_STEREO,	A52_3F},
	{A52_CHANNEL,	A52_DOLBY,	A52_STEREO,	A52_STEREO,
	 A52_2F1R,	A52_2F1R,	A52_2F1R,	A52_2F1R},
	{A52_CHANNEL,	A52_DOLBY,	A52_STEREO,	A52_STEREO,
	 A52_2F1R,	A52_3F1R,	A52_2F1R,	A52_3F1R},
	{A52_CHANNEL,	A52_DOLBY,	A52_STEREO,	A52_3F,
	 A52_2F2R,	A52_2F2R,	A52_2F2R,	A52_2F2R},
	{A52_CHANNEL,	A52_DOLBY,	A52_STEREO,	A52_3F,
	 A52_2F2R,	A52_3F2R,	A52_2F2R,	A52_3F2R},
	{A52_CHANNEL1,	A52_MONO,	A52_MONO,	A52_MONO,
	 A52_MONO,	A52_MONO,	A52_MONO,	A52_MONO},
	{A52_CHANNEL2,	A52_MONO,	A52_MONO,	A52_MONO,
	 A52_MONO,	A52_MONO,	A52_MONO,	A52_MONO},
	{A52_CHANNEL,	A52_DOLBY,	A52_STEREO,	A52_DOLBY,
	 A52_DOLBY,	A52_DOLBY,	A52_DOLBY,	A52_DOLBY}
    };
    int output;

    output = flags & A52_CHANNEL_MASK;
    if (output > A52_DOLBY)
	return -1;

    output = table[output][input & 7];

    if ((output == A52_STEREO) &&
	((input == A52_DOLBY) || ((input == A52_3F) && (clev == LEVEL_3DB))))
	output = A52_DOLBY;

    if (flags & A52_ADJUST_LEVEL)
	switch (CONVERT (input & 7, output)) {

	case CONVERT (A52_3F, A52_MONO):
	    *level *= LEVEL_3DB / (1 + clev);
	    break;

	case CONVERT (A52_STEREO, A52_MONO):
	case CONVERT (A52_2F2R, A52_2F1R):
	case CONVERT (A52_3F2R, A52_3F1R):
	level_3db:
	    *level *= LEVEL_3DB;
	    break;

	case CONVERT (A52_3F2R, A52_2F1R):
	    if (clev < LEVEL_PLUS3DB - 1)
		goto level_3db;
	    /* break thru */
	case CONVERT (A52_3F, A52_STEREO):
	case CONVERT (A52_3F1R, A52_2F1R):
	case CONVERT (A52_3F1R, A52_2F2R):
	case CONVERT (A52_3F2R, A52_2F2R):
	    *level /= 1 + clev;
	    break;

	case CONVERT (A52_2F1R, A52_MONO):
	    *level *= LEVEL_PLUS3DB / (2 + slev);
	    break;

	case CONVERT (A52_2F1R, A52_STEREO):
	case CONVERT (A52_3F1R, A52_3F):
	    *level /= 1 + slev * LEVEL_3DB;
	    break;

	case CONVERT (A52_3F1R, A52_MONO):
	    *level *= LEVEL_3DB / (1 + clev + 0.5 * slev);
	    break;

	case CONVERT (A52_3F1R, A52_STEREO):
	    *level /= 1 + clev + slev * LEVEL_3DB;
	    break;

	case CONVERT (A52_2F2R, A52_MONO):
	    *level *= LEVEL_3DB / (1 + slev);
	    break;

	case CONVERT (A52_2F2R, A52_STEREO):
	case CONVERT (A52_3F2R, A52_3F):
	    *level /= 1 + slev;
	    break;

	case CONVERT (A52_3F2R, A52_MONO):
	    *level *= LEVEL_3DB / (1 + clev + slev);
	    break;

	case CONVERT (A52_3F2R, A52_STEREO):
	    *level /= 1 + clev + slev;
	    break;

	case CONVERT (A52_MONO, A52_DOLBY):
	    *level *= LEVEL_PLUS3DB;
	    break;

	case CONVERT (A52_3F, A52_DOLBY):
	case CONVERT (A52_2F1R, A52_DOLBY):
	    *level *= 1 / (1 + LEVEL_3DB);
	    break;

	case CONVERT (A52_3F1R, A52_DOLBY):
	case CONVERT (A52_2F2R, A52_DOLBY):
	    *level *= 1 / (1 + 2 * LEVEL_3DB);
	    break;

	case CONVERT (A52_3F2R, A52_DOLBY):
	    *level *= 1 / (1 + 3 * LEVEL_3DB);
	    break;
	}

    return output;
}

int a52_downmix_coeff (sample_t * coeff, int acmod, int output, sample_t level,
		       sample_t clev, sample_t slev)
{
    switch (CONVERT (acmod, output & A52_CHANNEL_MASK)) {

    case CONVERT (A52_CHANNEL, A52_CHANNEL):
    case CONVERT (A52_MONO, A52_MONO):
    case CONVERT (A52_STEREO, A52_STEREO):
    case CONVERT (A52_3F, A52_3F):
    case CONVERT (A52_2F1R, A52_2F1R):
    case CONVERT (A52_3F1R, A52_3F1R):
    case CONVERT (A52_2F2R, A52_2F2R):
    case CONVERT (A52_3F2R, A52_3F2R):
    case CONVERT (A52_STEREO, A52_DOLBY):
	coeff[0] = coeff[1] = coeff[2] = coeff[3] = coeff[4] = level;
	return 0;

    case CONVERT (A52_CHANNEL, A52_MONO):
	coeff[0] = coeff[1] = level * LEVEL_6DB;
	return 3;

    case CONVERT (A52_STEREO, A52_MONO):
	coeff[0] = coeff[1] = level * LEVEL_3DB;
	return 3;

    case CONVERT (A52_3F, A52_MONO):
	coeff[0] = coeff[2] = level * LEVEL_3DB;
	coeff[1] = level * clev * LEVEL_PLUS3DB;
	return 7;

    case CONVERT (A52_2F1R, A52_MONO):
	coeff[0] = coeff[1] = level * LEVEL_3DB;
	coeff[2] = level * slev * LEVEL_3DB;
	return 7;

    case CONVERT (A52_2F2R, A52_MONO):
	coeff[0] = coeff[1] = level * LEVEL_3DB;
	coeff[2] = coeff[3] = level * slev * LEVEL_3DB;
	return 15;

    case CONVERT (A52_3F1R, A52_MONO):
	coeff[0] = coeff[2] = level * LEVEL_3DB;
	coeff[1] = level * clev * LEVEL_PLUS3DB;
	coeff[3] = level * slev * LEVEL_3DB;
	return 15;

    case CONVERT (A52_3F2R, A52_MONO):
	coeff[0] = coeff[2] = level * LEVEL_3DB;
	coeff[1] = level * clev * LEVEL_PLUS3DB;
	coeff[3] = coeff[4] = level * slev * LEVEL_3DB;
	return 31;

    case CONVERT (A52_MONO, A52_DOLBY):
	coeff[0] = level * LEVEL_3DB;
	return 0;

    case CONVERT (A52_3F, A52_DOLBY):
	clev = LEVEL_3DB;
    case CONVERT (A52_3F, A52_STEREO):
    case CONVERT (A52_3F1R, A52_2F1R):
    case CONVERT (A52_3F2R, A52_2F2R):
	coeff[0] = coeff[2] = coeff[3] = coeff[4] = level;
	coeff[1] = level * clev;
	return 7;

    case CONVERT (A52_2F1R, A52_DOLBY):
	slev = 1;
    case CONVERT (A52_2F1R, A52_STEREO):
	coeff[0] = coeff[1] = level;
	coeff[2] = level * slev * LEVEL_3DB;
	return 7;

    case CONVERT (A52_3F1R, A52_DOLBY):
	clev = LEVEL_3DB;
	slev = 1;
    case CONVERT (A52_3F1R, A52_STEREO):
	coeff[0] = coeff[2] = level;
	coeff[1] = level * clev;
	coeff[3] = level * slev * LEVEL_3DB;
	return 15;

    case CONVERT (A52_2F2R, A52_DOLBY):
	slev = LEVEL_3DB;
    case CONVERT (A52_2F2R, A52_STEREO):
	coeff[0] = coeff[1] = level;
	coeff[2] = coeff[3] = level * slev;
	return 15;

    case CONVERT (A52_3F2R, A52_DOLBY):
	clev = LEVEL_3DB;
    case CONVERT (A52_3F2R, A52_2F1R):
	slev = LEVEL_3DB;
    case CONVERT (A52_3F2R, A52_STEREO):
	coeff[0] = coeff[2] = level;
	coeff[1] = level * clev;
	coeff[3] = coeff[4] = level * slev;
	return 31;

    case CONVERT (A52_3F1R, A52_3F):
	coeff[0] = coeff[1] = coeff[2] = level;
	coeff[3] = level * slev * LEVEL_3DB;
	return 13;

    case CONVERT (A52_3F2R, A52_3F):
	coeff[0] = coeff[1] = coeff[2] = level;
	coeff[3] = coeff[4] = level * slev;
	return 29;

    case CONVERT (A52_2F2R, A52_2F1R):
	coeff[0] = coeff[1] = level;
	coeff[2] = coeff[3] = level * LEVEL_3DB;
	return 12;

    case CONVERT (A52_3F2R, A52_3F1R):
	coeff[0] = coeff[1] = coeff[2] = level;
	coeff[3] = coeff[4] = level * LEVEL_3DB;
	return 24;

    case CONVERT (A52_2F1R, A52_2F2R):
	coeff[0] = coeff[1] = level;
	coeff[2] = level * LEVEL_3DB;
	return 0;

    case CONVERT (A52_3F1R, A52_2F2R):
	coeff[0] = coeff[2] = level;
	coeff[1] = level * clev;
	coeff[3] = level * LEVEL_3DB;
	return 7;

    case CONVERT (A52_3F1R, A52_3F2R):
	coeff[0] = coeff[1] = coeff[2] = level;
	coeff[3] = level * LEVEL_3DB;
	return 0;

    case CONVERT (A52_CHANNEL, A52_CHANNEL1):
	coeff[0] = level;
	coeff[1] = 0;
	return 0;

    case CONVERT (A52_CHANNEL, A52_CHANNEL2):
	coeff[0] = 0;
	coeff[1] = level;
	return 0;
    }

    return -1;	/* NOTREACHED */
}

static void mix2to1 (sample_t * dest, sample_t * src, sample_t bias)
{
    int i;

    for (i = 0; i < 256; i++)
	dest[i] += src[i] + bias;
}

static void mix3to1 (sample_t * samples, sample_t bias)
{
    int i;

    for (i = 0; i < 256; i++)
	samples[i] += samples[i + 256] + samples[i + 512] + bias;
}

static void mix4to1 (sample_t * samples, sample_t bias)
{
    int i;

    for (i = 0; i < 256; i++)
	samples[i] += (samples[i + 256] + samples[i + 512] +
		       samples[i + 768] + bias);
}

static void mix5to1 (sample_t * samples, sample_t bias)
{
    int i;

    for (i = 0; i < 256; i++)