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1/*
2** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
3** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
4**
5** This program is free software; you can redistribute it and/or modify
6** it under the terms of the GNU General Public License as published by
7** the Free Software Foundation; either version 2 of the License, or
8** (at your option) any later version.
9**
10** This program is distributed in the hope that it will be useful,
11** but WITHOUT ANY WARRANTY; without even the implied warranty of
12** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13** GNU General Public License for more details.
14**
15** You should have received a copy of the GNU General Public License
16** along with this program; if not, write to the Free Software
17** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18**
19** Any non-GPL usage of this software or parts of this software is strictly
20** forbidden.
21**
22** Commercial non-GPL licensing of this software is possible.
23** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
24**
25** $Id$
26**/
27
28#include "common.h"
29#include "structs.h"
30
31#include "syntax.h"
32#include "tns.h"
33
34
35/* static function declarations */
36static void tns_decode_coef(uint8_t order, uint8_t coef_res_bits, uint8_t coef_compress,
37 uint8_t *coef, real_t *a);
38static void tns_ar_filter(real_t *spectrum, uint16_t size, int8_t inc, real_t *lpc,
39 int8_t order);
40#ifdef LTP_DEC
41static void tns_ma_filter(real_t *spectrum, uint16_t size, int8_t inc, real_t *lpc,
42 int8_t order);
43#endif
44
45
46#ifdef _MSC_VER
47#pragma warning(disable:4305)
48#pragma warning(disable:4244)
49#endif
50static real_t tns_coef_0_3[] =
51{
52 COEF_CONST(0.0), COEF_CONST(0.4338837391), COEF_CONST(0.7818314825), COEF_CONST(0.9749279122),
53 COEF_CONST(-0.9848077530), COEF_CONST(-0.8660254038), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
54 COEF_CONST(-0.4338837391), COEF_CONST(-0.7818314825), COEF_CONST(-0.9749279122), COEF_CONST(-0.9749279122),
55 COEF_CONST(-0.9848077530), COEF_CONST(-0.8660254038), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433)
56};
57static real_t tns_coef_0_4[] =
58{
59 COEF_CONST(0.0), COEF_CONST(0.2079116908), COEF_CONST(0.4067366431), COEF_CONST(0.5877852523),
60 COEF_CONST(0.7431448255), COEF_CONST(0.8660254038), COEF_CONST(0.9510565163), COEF_CONST(0.9945218954),
61 COEF_CONST(-0.9957341763), COEF_CONST(-0.9618256432), COEF_CONST(-0.8951632914), COEF_CONST(-0.7980172273),
62 COEF_CONST(-0.6736956436), COEF_CONST(-0.5264321629), COEF_CONST(-0.3612416662), COEF_CONST(-0.1837495178)
63};
64static real_t tns_coef_1_3[] =
65{
66 COEF_CONST(0.0), COEF_CONST(0.4338837391), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
67 COEF_CONST(0.9749279122), COEF_CONST(0.7818314825), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
68 COEF_CONST(-0.4338837391), COEF_CONST(-0.7818314825), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433),
69 COEF_CONST(-0.7818314825), COEF_CONST(-0.4338837391), COEF_CONST(-0.6427876097), COEF_CONST(-0.3420201433)
70};
71static real_t tns_coef_1_4[] =
72{
73 COEF_CONST(0.0), COEF_CONST(0.2079116908), COEF_CONST(0.4067366431), COEF_CONST(0.5877852523),
74 COEF_CONST(-0.6736956436), COEF_CONST(-0.5264321629), COEF_CONST(-0.3612416662), COEF_CONST(-0.1837495178),
75 COEF_CONST(0.9945218954), COEF_CONST(0.9510565163), COEF_CONST(0.8660254038), COEF_CONST(0.7431448255),
76 COEF_CONST(-0.6736956436), COEF_CONST(-0.5264321629), COEF_CONST(-0.3612416662), COEF_CONST(-0.1837495178)
77};
78
79
80/* TNS decoding for one channel and frame */
81void tns_decode_frame(ic_stream *ics, tns_info *tns, uint8_t sr_index,
82 uint8_t object_type, real_t *spec, uint16_t frame_len)
83{
84 uint8_t w, f, tns_order;
85 int8_t inc;
86 int16_t size;
87 uint16_t bottom, top, start, end;
88 uint16_t nshort = frame_len/8;
89 real_t lpc[TNS_MAX_ORDER+1];
90
91 if (!ics->tns_data_present)
92 return;
93
94 for (w = 0; w < ics->num_windows; w++)
95 {
96 bottom = ics->num_swb;
97
98 for (f = 0; f < tns->n_filt[w]; f++)
99 {
100 top = bottom;
101 bottom = max(top - tns->length[w][f], 0);
102 tns_order = min(tns->order[w][f], TNS_MAX_ORDER);
103 if (!tns_order)
104 continue;
105
106 tns_decode_coef(tns_order, tns->coef_res[w]+3,
107 tns->coef_compress[w][f], tns->coef[w][f], lpc);
108
109 start = min(bottom, max_tns_sfb(sr_index, object_type, (ics->window_sequence == EIGHT_SHORT_SEQUENCE)));
110 start = min(start, ics->max_sfb);
111 start = ics->swb_offset[start];
112
113 end = min(top, max_tns_sfb(sr_index, object_type, (ics->window_sequence == EIGHT_SHORT_SEQUENCE)));
114 end = min(end, ics->max_sfb);
115 end = ics->swb_offset[end];
116
117 size = end - start;
118 if (size <= 0)
119 continue;
120
121 if (tns->direction[w][f])
122 {
123 inc = -1;
124 start = end - 1;
125 } else {
126 inc = 1;
127 }
128
129 tns_ar_filter(&spec[(w*nshort)+start], size, inc, lpc, tns_order);
130 }
131 }
132}
133
134#ifdef LTP_DEC
135/* TNS encoding for one channel and frame */
136void tns_encode_frame(ic_stream *ics, tns_info *tns, uint8_t sr_index,
137 uint8_t object_type, real_t *spec, uint16_t frame_len)
138{
139 uint8_t w, f, tns_order;
140 int8_t inc;
141 int16_t size;
142 uint16_t bottom, top, start, end;
143 uint16_t nshort = frame_len/8;
144 real_t lpc[TNS_MAX_ORDER+1];
145
146 if (!ics->tns_data_present)
147 return;
148
149 for (w = 0; w < ics->num_windows; w++)
150 {
151 bottom = ics->num_swb;
152
153 for (f = 0; f < tns->n_filt[w]; f++)
154 {
155 top = bottom;
156 bottom = max(top - tns->length[w][f], 0);
157 tns_order = min(tns->order[w][f], TNS_MAX_ORDER);
158 if (!tns_order)
159 continue;
160
161 tns_decode_coef(tns_order, tns->coef_res[w]+3,
162 tns->coef_compress[w][f], tns->coef[w][f], lpc);
163
164 start = min(bottom, max_tns_sfb(sr_index, object_type, (ics->window_sequence == EIGHT_SHORT_SEQUENCE)));
165 start = min(start, ics->max_sfb);
166 start = ics->swb_offset[start];
167
168 end = min(top, max_tns_sfb(sr_index, object_type, (ics->window_sequence == EIGHT_SHORT_SEQUENCE)));
169 end = min(end, ics->max_sfb);
170 end = ics->swb_offset[end];
171
172 size = end - start;
173 if (size <= 0)
174 continue;
175
176 if (tns->direction[w][f])
177 {
178 inc = -1;
179 start = end - 1;
180 } else {
181 inc = 1;
182 }
183
184 tns_ma_filter(&spec[(w*nshort)+start], size, inc, lpc, tns_order);
185 }
186 }
187}
188#endif
189
190/* Decoder transmitted coefficients for one TNS filter */
191static void tns_decode_coef(uint8_t order, uint8_t coef_res_bits, uint8_t coef_compress,
192 uint8_t *coef, real_t *a)
193{
194 uint8_t i, m;
195 real_t tmp2[TNS_MAX_ORDER+1], b[TNS_MAX_ORDER+1];
196
197 /* Conversion to signed integer */
198 for (i = 0; i < order; i++)
199 {
200 if (coef_compress == 0)
201 {
202 if (coef_res_bits == 3)
203 {
204 tmp2[i] = tns_coef_0_3[coef[i]];
205 } else {
206 tmp2[i] = tns_coef_0_4[coef[i]];
207 }
208 } else {
209 if (coef_res_bits == 3)
210 {
211 tmp2[i] = tns_coef_1_3[coef[i]];
212 } else {
213 tmp2[i] = tns_coef_1_4[coef[i]];
214 }
215 }
216 }
217
218 /* Conversion to LPC coefficients */
219 a[0] = COEF_CONST(1.0);
220 for (m = 1; m <= order; m++)
221 {
222 for (i = 1; i < m; i++) /* loop only while i<m */
223 b[i] = a[i] + MUL_C(tmp2[m-1], a[m-i]);
224
225 for (i = 1; i < m; i++) /* loop only while i<m */
226 a[i] = b[i];
227
228 a[m] = tmp2[m-1]; /* changed */
229 }
230}
231
232static void tns_ar_filter(real_t *spectrum, uint16_t size, int8_t inc, real_t *lpc,
233 int8_t order)
234{
235 /*
236 - Simple all-pole filter of order "order" defined by
237 y(n) = x(n) - lpc[1]*y(n-1) - ... - lpc[order]*y(n-order)
238 - The state variables of the filter are initialized to zero every time
239 - The output data is written over the input data ("in-place operation")
240 - An input vector of "size" samples is processed and the index increment
241 to the next data sample is given by "inc"
242 */
243
244 uint8_t j;
245 uint16_t i;
246 real_t y;
247 /* state is stored as a double ringbuffer */
248 real_t state[2*TNS_MAX_ORDER] = {0};
249 int8_t state_index = 0;
250
251 for (i = 0; i < size; i++)
252 {
253 y = *spectrum;
254
255 for (j = 0; j < order; j++)
256 y -= MUL_C(state[state_index+j], lpc[j+1]);
257
258 /* double ringbuffer state */
259 state_index--;
260 if (state_index < 0)
261 state_index = order-1;
262 state[state_index] = state[state_index + order] = y;
263
264 *spectrum = y;
265 spectrum += inc;
266
267//#define TNS_PRINT
268#ifdef TNS_PRINT
269 //printf("%d\n", y);
270 printf("0x%.8X\n", y);
271#endif
272 }
273}
274
275#ifdef LTP_DEC
276static void tns_ma_filter(real_t *spectrum, uint16_t size, int8_t inc, real_t *lpc,
277 int8_t order)
278{
279 /*
280 - Simple all-zero filter of order "order" defined by
281 y(n) = x(n) + a(2)*x(n-1) + ... + a(order+1)*x(n-order)
282 - The state variables of the filter are initialized to zero every time
283 - The output data is written over the input data ("in-place operation")
284 - An input vector of "size" samples is processed and the index increment
285 to the next data sample is given by "inc"
286 */
287
288 uint8_t j;
289 uint16_t i;
290 real_t y;
291 /* state is stored as a double ringbuffer */
292 real_t state[2*TNS_MAX_ORDER] = {0};
293 int8_t state_index = 0;
294
295 for (i = 0; i < size; i++)
296 {
297 y = *spectrum;
298
299 for (j = 0; j < order; j++)
300 y += MUL_C(state[j], lpc[j+1]);
301
302 /* double ringbuffer state */
303 state_index--;
304 if (state_index < 0)
305 state_index = order-1;
306 state[state_index] = state[state_index + order] = *spectrum;
307
308 *spectrum = y;
309 spectrum += inc;
310 }
311}
312#endif