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vdr/ac3dec/downmix.c

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2001-08-03 14:18:08 +02:00
/*
*
* downmix.c
*
* Copyright (C) Aaron Holtzman - Sept 1999
*
* Originally based on code by Yuqing Deng.
*
* This file is part of ac3dec, a free Dolby AC-3 stream decoder.
*
* ac3dec 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, or (at your option)
* any later version.
*
* ac3dec 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 GNU Make; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "ac3.h"
#include "ac3_internal.h"
#include "decode.h"
#include "downmix.h"
#include "debug.h"
//Pre-scaled downmix coefficients
static float cmixlev_lut[4] = { 0.2928, 0.2468, 0.2071, 0.2468 };
static float smixlev_lut[4] = { 0.2928, 0.2071, 0.0 , 0.2071 };
static void
downmix_3f_2r_to_2ch(bsi_t* bsi, stream_samples_t samples,sint_16 *s16_samples)
{
uint_32 j;
float right_tmp;
float left_tmp;
float clev,slev;
float *centre = 0, *left = 0, *right = 0, *left_sur = 0, *right_sur = 0;
left = samples[0];
centre = samples[1];
right = samples[2];
left_sur = samples[3];
right_sur = samples[4];
clev = cmixlev_lut[bsi->cmixlev];
slev = smixlev_lut[bsi->surmixlev];
#if defined DOLBY_SURROUND
for (j = 0; j < 256; j++)
{
right_tmp = *left_sur++ + *right_sur++;
left_tmp = 1.4142f * *left++ + *centre - right_tmp;
right_tmp += 1.4142f * *right++ + *centre++;
s16_samples[j * 2 ] = (sint_16) (left_tmp * 16000.0f);
s16_samples[j * 2 + 1] = (sint_16) (right_tmp * 16000.0f);
}
#else
for (j = 0; j < 256; j++)
{
left_tmp = 0.4142f * *left++ + clev * *centre + slev * *left_sur++;
right_tmp= 0.4142f * *right++ + clev * *centre++ + slev * *right_sur++;
s16_samples[j * 2 ] = (sint_16) (left_tmp * 32767.0f);
s16_samples[j * 2 + 1] = (sint_16) (right_tmp * 32767.0f);
}
#endif
}
static void
downmix_2f_2r_to_2ch(bsi_t* bsi, stream_samples_t samples,sint_16 *s16_samples)
{
uint_32 j;
float right_tmp;
float left_tmp;
float slev;
float *left = 0, *right = 0, *left_sur = 0, *right_sur = 0;
left = samples[0];
right = samples[1];
left_sur = samples[2];
right_sur = samples[3];
slev = smixlev_lut[bsi->surmixlev];
for (j = 0; j < 256; j++)
{
left_tmp = 0.4142f * *left++ + slev * *left_sur++;
right_tmp= 0.4142f * *right++ + slev * *right_sur++;
s16_samples[j * 2 ] = (sint_16) (left_tmp * 32767.0f);
s16_samples[j * 2 + 1] = (sint_16) (right_tmp * 32767.0f);
}
}
static void
downmix_3f_1r_to_2ch(bsi_t* bsi, stream_samples_t samples,sint_16 *s16_samples)
{
uint_32 j;
float right_tmp;
float left_tmp;
float clev,slev;
float *centre = 0, *left = 0, *right = 0, *sur = 0;
left = samples[0];
centre = samples[1];
right = samples[2];
//Mono surround
sur = samples[3];
clev = cmixlev_lut[bsi->cmixlev];
slev = smixlev_lut[bsi->surmixlev];
for (j = 0; j < 256; j++)
{
left_tmp = 0.4142f * *left++ + clev * *centre++ + slev * *sur;
right_tmp= 0.4142f * *right++ + clev * *centre + slev * *sur++;
s16_samples[j * 2 ] = (sint_16) (left_tmp * 32767.0f);
s16_samples[j * 2 + 1] = (sint_16) (right_tmp * 32767.0f);
}
}
static void
downmix_2f_1r_to_2ch(bsi_t* bsi, stream_samples_t samples,sint_16 *s16_samples)
{
uint_32 j;
float right_tmp;
float left_tmp;
float slev;
float *left = 0, *right = 0, *sur = 0;
left = samples[0];
right = samples[1];
//Mono surround
sur = samples[2];
slev = smixlev_lut[bsi->surmixlev];
for (j = 0; j < 256; j++)
{
left_tmp = 0.4142f * *left++ + slev * *sur;
right_tmp= 0.4142f * *right++ + slev * *sur++;
s16_samples[j * 2 ] = (sint_16) (left_tmp * 32767.0f);
s16_samples[j * 2 + 1] = (sint_16) (right_tmp * 32767.0f);
}
}
static void
downmix_3f_0r_to_2ch(bsi_t* bsi, stream_samples_t samples,sint_16 *s16_samples)
{
uint_32 j;
float right_tmp;
float left_tmp;
float clev;
float *centre = 0, *left = 0, *right = 0;
left = samples[0];
centre = samples[1];
right = samples[2];
clev = cmixlev_lut[bsi->cmixlev];
for (j = 0; j < 256; j++)
{
left_tmp = 0.4142f * *left++ + clev * *centre;
right_tmp= 0.4142f * *right++ + clev * *centre++;
s16_samples[j * 2 ] = (sint_16) (left_tmp * 32767.0f);
s16_samples[j * 2 + 1] = (sint_16) (right_tmp * 32767.0f);
}
}
static void
downmix_2f_0r_to_2ch(bsi_t* bsi, stream_samples_t samples,sint_16 *s16_samples)
{
uint_32 j;
float *left = 0, *right = 0;
left = samples[0];
right = samples[1];
for (j = 0; j < 256; j++)
{
s16_samples[j * 2 ] = (sint_16) (*left++ * 32767.0f);
s16_samples[j * 2 + 1] = (sint_16) (*right++ * 32767.0f);
}
}
static void
downmix_1f_0r_to_2ch(float *centre,sint_16 *s16_samples)
{
uint_32 j;
float tmp;
//Mono program!
for (j = 0; j < 256; j++)
{
tmp = 32767.0f * 0.7071f * *centre++;
s16_samples[j * 2 ] = s16_samples[j * 2 + 1] = (sint_16) tmp;
}
}
//
// Downmix into 2 or 4 channels (4 ch isn't in quite yet)
//
// The downmix function names have the following format
//
// downmix_Xf_Yr_to_[2|4]ch[_dolby]
//
// where X = number of front channels
// Y = number of rear channels
// [2|4] = number of output channels
// [_dolby] = with or without dolby surround mix
//
void downmix(bsi_t* bsi, stream_samples_t samples,sint_16 *s16_samples)
{
if(bsi->acmod > 7)
dprintf("(downmix) invalid acmod number\n");
//
//There are two main cases, with or without Dolby Surround
//
if(ac3_config.flags & AC3_DOLBY_SURR_ENABLE)
{
fprintf(stderr,"Dolby Surround Mixes not currently enabled\n");
exit(1);
}
//Non-Dolby surround downmixes
switch(bsi->acmod)
{
// 3/2
case 7:
downmix_3f_2r_to_2ch(bsi,samples,s16_samples);
break;
// 2/2
case 6:
downmix_2f_2r_to_2ch(bsi,samples,s16_samples);
break;
// 3/1
case 5:
downmix_3f_1r_to_2ch(bsi,samples,s16_samples);
break;
// 2/1
case 4:
downmix_2f_1r_to_2ch(bsi,samples,s16_samples);
break;
// 3/0
case 3:
downmix_3f_0r_to_2ch(bsi,samples,s16_samples);
break;
case 2:
downmix_2f_0r_to_2ch(bsi,samples,s16_samples);
break;
// 1/0
case 1:
downmix_1f_0r_to_2ch(samples[0],s16_samples);
break;
// 1+1
case 0:
downmix_1f_0r_to_2ch(samples[ac3_config.dual_mono_ch_sel],s16_samples);
break;
}
}
#if 0
//the dolby mixes lay here for the time being
switch(bsi->acmod)
{
// 3/2
case 7:
left = samples[0];
centre = samples[1];
right = samples[2];
left_sur = samples[3];
right_sur = samples[4];
for (j = 0; j < 256; j++)
{
right_tmp = 0.2265f * *left_sur++ + 0.2265f * *right_sur++;
left_tmp = -1 * right_tmp;
right_tmp += 0.3204f * *right++ + 0.2265f * *centre;
left_tmp += 0.3204f * *left++ + 0.2265f * *centre++;
samples[1][j] = right_tmp;
samples[0][j] = left_tmp;
}
break;
// 2/2
case 6:
left = samples[0];
right = samples[1];
left_sur = samples[2];
right_sur = samples[3];
for (j = 0; j < 256; j++)
{
right_tmp = 0.2265f * *left_sur++ + 0.2265f * *right_sur++;
left_tmp = -1 * right_tmp;
right_tmp += 0.3204f * *right++;
left_tmp += 0.3204f * *left++ ;
samples[1][j] = right_tmp;
samples[0][j] = left_tmp;
}
break;
// 3/1
case 5:
left = samples[0];
centre = samples[1];
right = samples[2];
//Mono surround
right_sur = samples[3];
for (j = 0; j < 256; j++)
{
right_tmp = 0.2265f * *right_sur++;
left_tmp = -1 * right_tmp;
right_tmp += 0.3204f * *right++ + 0.2265f * *centre;
left_tmp += 0.3204f * *left++ + 0.2265f * *centre++;
samples[1][j] = right_tmp;
samples[0][j] = left_tmp;
}
break;
// 2/1
case 4:
left = samples[0];
right = samples[1];
//Mono surround
right_sur = samples[2];
for (j = 0; j < 256; j++)
{
right_tmp = 0.2265f * *right_sur++;
left_tmp = -1 * right_tmp;
right_tmp += 0.3204f * *right++;
left_tmp += 0.3204f * *left++;
samples[1][j] = right_tmp;
samples[0][j] = left_tmp;
}
break;
// 3/0
case 3:
left = samples[0];
centre = samples[1];
right = samples[2];
for (j = 0; j < 256; j++)
{
right_tmp = 0.3204f * *right++ + 0.2265f * *centre;
left_tmp = 0.3204f * *left++ + 0.2265f * *centre++;
samples[1][j] = right_tmp;
samples[0][j] = left_tmp;
}
break;
// 2/0
case 2:
//Do nothing!
break;
// 1/0
case 1:
//Mono program!
right = samples[0];
for (j = 0; j < 256; j++)
{
right_tmp = 0.7071f * *right++;
samples[1][j] = right_tmp;
samples[0][j] = right_tmp;
}
break;
// 1+1
case 0:
//Dual mono, output selected by user
right = samples[ac3_config.dual_mono_ch_sel];
for (j = 0; j < 256; j++)
{
right_tmp = 0.7071f * *right++;
samples[1][j] = right_tmp;
samples[0][j] = right_tmp;
}
break;
#endif