mirror of
https://github.com/mpv-player/mpv
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5f5e40c155
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@14728 b3059339-0415-0410-9bf9-f77b7e298cf2
307 lines
10 KiB
C
307 lines
10 KiB
C
/*
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** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
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** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
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**
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** This program 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 of the License, or
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** (at your option) any later version.
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**
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** This program 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 this program; if not, write to the Free Software
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** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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**
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** Any non-GPL usage of this software or parts of this software is strictly
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** forbidden.
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**
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** Commercial non-GPL licensing of this software is possible.
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** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
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**
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** $Id: tns.c,v 1.33 2004/06/30 12:45:57 menno Exp $
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**/
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#include "common.h"
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#include "structs.h"
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#include "syntax.h"
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#include "tns.h"
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/* static function declarations */
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static void tns_decode_coef(uint8_t order, uint8_t coef_res_bits, uint8_t coef_compress,
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uint8_t *coef, real_t *a);
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static void tns_ar_filter(real_t *spectrum, uint16_t size, int8_t inc, real_t *lpc,
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uint8_t order);
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static void tns_ma_filter(real_t *spectrum, uint16_t size, int8_t inc, real_t *lpc,
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uint8_t order);
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#ifdef _MSC_VER
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#pragma warning(disable:4305)
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#pragma warning(disable:4244)
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#endif
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static real_t tns_coef_0_3[] =
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{
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COEF_CONST(0.0), COEF_CONST(0.4338837391), COEF_CONST(0.7818314825), COEF_CONST(0.9749279122),
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COEF_CONST(-0.9848077530), COEF_CONST(-0.8660254038), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
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COEF_CONST(-0.4338837391), COEF_CONST(-0.7818314825), COEF_CONST(-0.9749279122), COEF_CONST(-0.9749279122),
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COEF_CONST(-0.9848077530), COEF_CONST(-0.8660254038), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433)
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};
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static real_t tns_coef_0_4[] =
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{
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COEF_CONST(0.0), COEF_CONST(0.2079116908), COEF_CONST(0.4067366431), COEF_CONST(0.5877852523),
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COEF_CONST(0.7431448255), COEF_CONST(0.8660254038), COEF_CONST(0.9510565163), COEF_CONST(0.9945218954),
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COEF_CONST(-0.9957341763), COEF_CONST(-0.9618256432), COEF_CONST(-0.8951632914), COEF_CONST(-0.7980172273),
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COEF_CONST(-0.6736956436), COEF_CONST(-0.5264321629), COEF_CONST(-0.3612416662), COEF_CONST(-0.1837495178)
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};
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static real_t tns_coef_1_3[] =
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{
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COEF_CONST(0.0), COEF_CONST(0.4338837391), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
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COEF_CONST(0.9749279122), COEF_CONST(0.7818314825), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
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COEF_CONST(-0.4338837391), COEF_CONST(-0.7818314825), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
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COEF_CONST(-0.7818314825), COEF_CONST(-0.4338837391), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433)
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};
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static real_t tns_coef_1_4[] =
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{
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COEF_CONST(0.0), COEF_CONST(0.2079116908), COEF_CONST(0.4067366431), COEF_CONST(0.5877852523),
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COEF_CONST(-0.6736956436), COEF_CONST(-0.5264321629), COEF_CONST(-0.3612416662), COEF_CONST(-0.1837495178),
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COEF_CONST(0.9945218954), COEF_CONST(0.9510565163), COEF_CONST(0.8660254038), COEF_CONST(0.7431448255),
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COEF_CONST(-0.6736956436), COEF_CONST(-0.5264321629), COEF_CONST(-0.3612416662), COEF_CONST(-0.1837495178)
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};
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/* TNS decoding for one channel and frame */
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void tns_decode_frame(ic_stream *ics, tns_info *tns, uint8_t sr_index,
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uint8_t object_type, real_t *spec, uint16_t frame_len)
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{
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uint8_t w, f, tns_order;
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int8_t inc;
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int16_t size;
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uint16_t bottom, top, start, end;
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uint16_t nshort = frame_len/8;
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real_t lpc[TNS_MAX_ORDER+1];
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if (!ics->tns_data_present)
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return;
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for (w = 0; w < ics->num_windows; w++)
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{
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bottom = ics->num_swb;
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for (f = 0; f < tns->n_filt[w]; f++)
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{
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top = bottom;
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bottom = max(top - tns->length[w][f], 0);
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tns_order = min(tns->order[w][f], TNS_MAX_ORDER);
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if (!tns_order)
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continue;
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tns_decode_coef(tns_order, tns->coef_res[w]+3,
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tns->coef_compress[w][f], tns->coef[w][f], lpc);
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start = min(bottom, max_tns_sfb(sr_index, object_type, (ics->window_sequence == EIGHT_SHORT_SEQUENCE)));
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start = min(start, ics->max_sfb);
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start = ics->swb_offset[start];
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end = min(top, max_tns_sfb(sr_index, object_type, (ics->window_sequence == EIGHT_SHORT_SEQUENCE)));
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end = min(end, ics->max_sfb);
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end = ics->swb_offset[end];
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size = end - start;
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if (size <= 0)
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continue;
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if (tns->direction[w][f])
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{
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inc = -1;
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start = end - 1;
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} else {
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inc = 1;
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}
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tns_ar_filter(&spec[(w*nshort)+start], size, inc, lpc, tns_order);
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}
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}
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}
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/* TNS encoding for one channel and frame */
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void tns_encode_frame(ic_stream *ics, tns_info *tns, uint8_t sr_index,
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uint8_t object_type, real_t *spec, uint16_t frame_len)
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{
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uint8_t w, f, tns_order;
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int8_t inc;
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int16_t size;
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uint16_t bottom, top, start, end;
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uint16_t nshort = frame_len/8;
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real_t lpc[TNS_MAX_ORDER+1];
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if (!ics->tns_data_present)
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return;
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for (w = 0; w < ics->num_windows; w++)
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{
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bottom = ics->num_swb;
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for (f = 0; f < tns->n_filt[w]; f++)
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{
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top = bottom;
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bottom = max(top - tns->length[w][f], 0);
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tns_order = min(tns->order[w][f], TNS_MAX_ORDER);
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if (!tns_order)
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continue;
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tns_decode_coef(tns_order, tns->coef_res[w]+3,
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tns->coef_compress[w][f], tns->coef[w][f], lpc);
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start = min(bottom, max_tns_sfb(sr_index, object_type, (ics->window_sequence == EIGHT_SHORT_SEQUENCE)));
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start = min(start, ics->max_sfb);
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start = ics->swb_offset[start];
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end = min(top, max_tns_sfb(sr_index, object_type, (ics->window_sequence == EIGHT_SHORT_SEQUENCE)));
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end = min(end, ics->max_sfb);
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end = ics->swb_offset[end];
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size = end - start;
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if (size <= 0)
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continue;
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if (tns->direction[w][f])
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{
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inc = -1;
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start = end - 1;
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} else {
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inc = 1;
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}
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tns_ma_filter(&spec[(w*nshort)+start], size, inc, lpc, tns_order);
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}
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}
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}
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/* Decoder transmitted coefficients for one TNS filter */
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static void tns_decode_coef(uint8_t order, uint8_t coef_res_bits, uint8_t coef_compress,
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uint8_t *coef, real_t *a)
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{
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uint8_t i, m;
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real_t tmp2[TNS_MAX_ORDER+1], b[TNS_MAX_ORDER+1];
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/* Conversion to signed integer */
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for (i = 0; i < order; i++)
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{
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if (coef_compress == 0)
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{
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if (coef_res_bits == 3)
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{
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tmp2[i] = tns_coef_0_3[coef[i]];
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} else {
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tmp2[i] = tns_coef_0_4[coef[i]];
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}
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} else {
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if (coef_res_bits == 3)
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{
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tmp2[i] = tns_coef_1_3[coef[i]];
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} else {
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tmp2[i] = tns_coef_1_4[coef[i]];
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}
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}
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}
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/* Conversion to LPC coefficients */
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a[0] = COEF_CONST(1.0);
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for (m = 1; m <= order; m++)
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{
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for (i = 1; i < m; i++) /* loop only while i<m */
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b[i] = a[i] + MUL_C(tmp2[m-1], a[m-i]);
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for (i = 1; i < m; i++) /* loop only while i<m */
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a[i] = b[i];
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a[m] = tmp2[m-1]; /* changed */
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}
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}
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static void tns_ar_filter(real_t *spectrum, uint16_t size, int8_t inc, real_t *lpc,
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uint8_t order)
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{
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/*
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- Simple all-pole filter of order "order" defined by
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y(n) = x(n) - lpc[1]*y(n-1) - ... - lpc[order]*y(n-order)
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- The state variables of the filter are initialized to zero every time
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- The output data is written over the input data ("in-place operation")
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- An input vector of "size" samples is processed and the index increment
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to the next data sample is given by "inc"
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*/
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uint8_t j;
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uint16_t i;
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real_t y;
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/* state is stored as a double ringbuffer */
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real_t state[2*TNS_MAX_ORDER] = {0};
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int8_t state_index = 0;
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for (i = 0; i < size; i++)
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{
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y = *spectrum;
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for (j = 0; j < order; j++)
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y -= MUL_C(state[state_index+j], lpc[j+1]);
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/* double ringbuffer state */
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state_index--;
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if (state_index < 0)
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state_index = order-1;
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state[state_index] = state[state_index + order] = y;
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*spectrum = y;
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spectrum += inc;
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//#define TNS_PRINT
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#ifdef TNS_PRINT
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//printf("%d\n", y);
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printf("0x%.8X\n", y);
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#endif
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}
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}
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static void tns_ma_filter(real_t *spectrum, uint16_t size, int8_t inc, real_t *lpc,
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uint8_t order)
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{
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/*
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- Simple all-zero filter of order "order" defined by
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y(n) = x(n) + a(2)*x(n-1) + ... + a(order+1)*x(n-order)
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- The state variables of the filter are initialized to zero every time
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- The output data is written over the input data ("in-place operation")
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- An input vector of "size" samples is processed and the index increment
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to the next data sample is given by "inc"
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*/
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uint8_t j;
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uint16_t i;
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real_t y;
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/* state is stored as a double ringbuffer */
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real_t state[2*TNS_MAX_ORDER] = {0};
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int8_t state_index = 0;
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for (i = 0; i < size; i++)
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{
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y = *spectrum;
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for (j = 0; j < order; j++)
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y += MUL_C(state[j], lpc[j+1]);
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/* double ringbuffer state */
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state_index--;
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if (state_index < 0)
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state_index = order-1;
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state[state_index] = state[state_index + order] = *spectrum;
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*spectrum = y;
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spectrum += inc;
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}
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}
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