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83 lines
1.9 KiB
C
83 lines
1.9 KiB
C
/*
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* rematrix.c
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*
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* Copyright (C) Aaron Holtzman - July 1999
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*
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* This file is part of ac3dec, a free Dolby AC-3 stream decoder.
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*
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* ac3dec is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* ac3dec is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU Make; see the file COPYING. If not, write to
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* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include "ac3.h"
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#include "ac3_internal.h"
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#include "decode.h"
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#include "rematrix.h"
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struct rematrix_band_s
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{
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uint_32 start;
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uint_32 end;
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};
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struct rematrix_band_s rematrix_band[] = { {13,24}, {25,36}, {37 ,60}, {61,252}};
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static inline uint_32 min(uint_32 a,uint_32 b);
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static inline uint_32
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min(uint_32 a,uint_32 b)
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{
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return (a < b ? a : b);
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}
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/* This routine simply does stereo rematixing for the 2 channel
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* stereo mode */
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void rematrix(audblk_t *audblk, stream_samples_t samples)
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{
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uint_32 num_bands;
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uint_32 start;
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uint_32 end;
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uint_32 i,j;
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float left,right;
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if(!audblk->cplinu || audblk->cplbegf > 2)
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num_bands = 4;
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else if (audblk->cplbegf > 0)
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num_bands = 3;
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else
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num_bands = 2;
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for(i=0;i < num_bands; i++)
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{
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if(!audblk->rematflg[i])
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continue;
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start = rematrix_band[i].start;
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end = min(rematrix_band[i].end ,12 * audblk->cplbegf + 36);
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for(j=start;j < end; j++)
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{
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left = samples[0][j] + samples[1][j];
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right = samples[0][j] - samples[1][j];
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samples[0][j] = left;
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samples[1][j] = right;
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}
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}
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}
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