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29 * AAC Spectral Band Replication decoding functions (fixed-point)
30 * Copyright (c) 2008-2009 Robert Swain ( rob opendot cl )
31 * Copyright (c) 2009-2010 Alex Converse <alex.converse@gmail.com>
33 * This file is part of FFmpeg.
35 * FFmpeg is free software; you can redistribute it and/or
36 * modify it under the terms of the GNU Lesser General Public
37 * License as published by the Free Software Foundation; either
38 * version 2.1 of the License, or (at your option) any later version.
40 * FFmpeg is distributed in the hope that it will be useful,
41 * but WITHOUT ANY WARRANTY; without even the implied warranty of
42 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
43 * Lesser General Public License for more details.
45 * You should have received a copy of the GNU Lesser General Public
46 * License along with FFmpeg; if not, write to the Free Software
47 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
52 * AAC Spectral Band Replication decoding functions (fixed-point)
53 * Note: Rounding-to-nearest used unless otherwise stated
54 * @author Robert Swain ( rob opendot cl )
55 * @author Stanislav Ocovaj ( stanislav.ocovaj imgtec com )
62 #include "aacsbrdata.h"
63 #include "aacsbr_fixed_tablegen.h"
67 #include "libavutil/internal.h"
68 #include "libavutil/libm.h"
69 #include "libavutil/avassert.h"
75 static VLC vlc_sbr[10];
76 static void aacsbr_func_ptr_init(AACSBRContext *c);
77 static const int CONST_LN2 = Q31(0.6931471806/256); // ln(2)/256
78 static const int CONST_RECIP_LN2 = Q31(0.7213475204); // 0.5/ln(2)
79 static const int CONST_076923 = Q31(0.76923076923076923077f);
81 static const int fixed_log_table[10] =
83 Q31(1.0/2), Q31(1.0/3), Q31(1.0/4), Q31(1.0/5), Q31(1.0/6),
84 Q31(1.0/7), Q31(1.0/8), Q31(1.0/9), Q31(1.0/10), Q31(1.0/11)
87 static int fixed_log(int x)
89 int i, ret, xpow, tmp;
93 for (i=0; i<10; i+=2){
94 xpow = (int)(((int64_t)xpow * x + 0x40000000) >> 31);
95 tmp = (int)(((int64_t)xpow * fixed_log_table[i] + 0x40000000) >> 31);
98 xpow = (int)(((int64_t)xpow * x + 0x40000000) >> 31);
99 tmp = (int)(((int64_t)xpow * fixed_log_table[i+1] + 0x40000000) >> 31);
106 static const int fixed_exp_table[7] =
108 Q31(1.0/2), Q31(1.0/6), Q31(1.0/24), Q31(1.0/120),
109 Q31(1.0/720), Q31(1.0/5040), Q31(1.0/40320)
112 static int fixed_exp(int x)
114 int i, ret, xpow, tmp;
119 xpow = (int)(((int64_t)xpow * x + 0x400000) >> 23);
120 tmp = (int)(((int64_t)xpow * fixed_exp_table[i] + 0x40000000) >> 31);
127 static void make_bands(int16_t* bands, int start, int stop, int num_bands)
129 int k, previous, present;
130 int base, prod, nz = 0;
132 base = (stop << 23) / start;
133 while (base < 0x40000000){
137 base = fixed_log(base - 0x80000000);
138 base = (((base + 0x80) >> 8) + (8-nz)*CONST_LN2) / num_bands;
139 base = fixed_exp(base);
144 for (k = 0; k < num_bands-1; k++) {
145 prod = (int)(((int64_t)prod * base + 0x400000) >> 23);
146 present = (prod + 0x400000) >> 23;
147 bands[k] = present - previous;
150 bands[num_bands-1] = stop - previous;
153 /// Dequantization and stereo decoding (14496-3 sp04 p203)
154 static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)
159 if (id_aac == TYPE_CPE && sbr->bs_coupling) {
160 int alpha = sbr->data[0].bs_amp_res ? 2 : 1;
161 int pan_offset = sbr->data[0].bs_amp_res ? 12 : 24;
162 for (e = 1; e <= sbr->data[0].bs_num_env; e++) {
163 for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {
164 SoftFloat temp1, temp2, fac;
166 temp1.exp = sbr->data[0].env_facs[e][k].mant * alpha + 14;
168 temp1.mant = 759250125;
170 temp1.mant = 0x20000000;
171 temp1.exp = (temp1.exp >> 1) + 1;
173 temp2.exp = (pan_offset - sbr->data[1].env_facs[e][k].mant) * alpha;
175 temp2.mant = 759250125;
177 temp2.mant = 0x20000000;
178 temp2.exp = (temp2.exp >> 1) + 1;
179 fac = av_div_sf(temp1, av_add_sf(FLOAT_1, temp2));
180 sbr->data[0].env_facs[e][k] = fac;
181 sbr->data[1].env_facs[e][k] = av_mul_sf(fac, temp2);
184 for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {
185 for (k = 0; k < sbr->n_q; k++) {
186 SoftFloat temp1, temp2, fac;
188 temp1.exp = NOISE_FLOOR_OFFSET - \
189 sbr->data[0].noise_facs[e][k].mant + 2;
190 temp1.mant = 0x20000000;
191 temp2.exp = 12 - sbr->data[1].noise_facs[e][k].mant + 1;
192 temp2.mant = 0x20000000;
193 fac = av_div_sf(temp1, av_add_sf(FLOAT_1, temp2));
194 sbr->data[0].noise_facs[e][k] = fac;
195 sbr->data[1].noise_facs[e][k] = av_mul_sf(fac, temp2);
198 } else { // SCE or one non-coupled CPE
199 for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {
200 int alpha = sbr->data[ch].bs_amp_res ? 2 : 1;
201 for (e = 1; e <= sbr->data[ch].bs_num_env; e++)
202 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++){
205 temp1.exp = alpha * sbr->data[ch].env_facs[e][k].mant + 12;
207 temp1.mant = 759250125;
209 temp1.mant = 0x20000000;
210 temp1.exp = (temp1.exp >> 1) + 1;
212 sbr->data[ch].env_facs[e][k] = temp1;
214 for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)
215 for (k = 0; k < sbr->n_q; k++){
216 sbr->data[ch].noise_facs[e][k].exp = NOISE_FLOOR_OFFSET - \
217 sbr->data[ch].noise_facs[e][k].mant + 1;
218 sbr->data[ch].noise_facs[e][k].mant = 0x20000000;
224 /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering
225 * (14496-3 sp04 p214)
226 * Warning: This routine does not seem numerically stable.
228 static void sbr_hf_inverse_filter(SBRDSPContext *dsp,
229 int (*alpha0)[2], int (*alpha1)[2],
230 const int X_low[32][40][2], int k0)
235 for (k = 0; k < k0; k++) {
236 SoftFloat phi[3][2][2];
237 SoftFloat a00, a01, a10, a11;
240 dsp->autocorrelate(X_low[k], phi);
242 dk = av_sub_sf(av_mul_sf(phi[2][1][0], phi[1][0][0]),
243 av_mul_sf(av_add_sf(av_mul_sf(phi[1][1][0], phi[1][1][0]),
244 av_mul_sf(phi[1][1][1], phi[1][1][1])), FLOAT_0999999));
250 SoftFloat temp_real, temp_im;
251 temp_real = av_sub_sf(av_sub_sf(av_mul_sf(phi[0][0][0], phi[1][1][0]),
252 av_mul_sf(phi[0][0][1], phi[1][1][1])),
253 av_mul_sf(phi[0][1][0], phi[1][0][0]));
254 temp_im = av_sub_sf(av_add_sf(av_mul_sf(phi[0][0][0], phi[1][1][1]),
255 av_mul_sf(phi[0][0][1], phi[1][1][0])),
256 av_mul_sf(phi[0][1][1], phi[1][0][0]));
258 a10 = av_div_sf(temp_real, dk);
259 a11 = av_div_sf(temp_im, dk);
262 if (!phi[1][0][0].mant) {
266 SoftFloat temp_real, temp_im;
267 temp_real = av_add_sf(phi[0][0][0],
268 av_add_sf(av_mul_sf(a10, phi[1][1][0]),
269 av_mul_sf(a11, phi[1][1][1])));
270 temp_im = av_add_sf(phi[0][0][1],
271 av_sub_sf(av_mul_sf(a11, phi[1][1][0]),
272 av_mul_sf(a10, phi[1][1][1])));
274 temp_real.mant = -temp_real.mant;
275 temp_im.mant = -temp_im.mant;
276 a00 = av_div_sf(temp_real, phi[1][0][0]);
277 a01 = av_div_sf(temp_im, phi[1][0][0]);
282 alpha0[k][0] = 0x7fffffff;
287 alpha0[k][0] = a00.mant;
289 round = 1 << (shift-1);
290 alpha0[k][0] = (a00.mant + round) >> shift;
296 alpha0[k][1] = 0x7fffffff;
301 alpha0[k][1] = a01.mant;
303 round = 1 << (shift-1);
304 alpha0[k][1] = (a01.mant + round) >> shift;
309 alpha1[k][0] = 0x7fffffff;
314 alpha1[k][0] = a10.mant;
316 round = 1 << (shift-1);
317 alpha1[k][0] = (a10.mant + round) >> shift;
323 alpha1[k][1] = 0x7fffffff;
328 alpha1[k][1] = a11.mant;
330 round = 1 << (shift-1);
331 alpha1[k][1] = (a11.mant + round) >> shift;
335 shift = (int)(((int64_t)(alpha1[k][0]>>1) * (alpha1[k][0]>>1) + \
336 (int64_t)(alpha1[k][1]>>1) * (alpha1[k][1]>>1) + \
338 if (shift >= 0x20000000){
345 shift = (int)(((int64_t)(alpha0[k][0]>>1) * (alpha0[k][0]>>1) + \
346 (int64_t)(alpha0[k][1]>>1) * (alpha0[k][1]>>1) + \
348 if (shift >= 0x20000000){
357 /// Chirp Factors (14496-3 sp04 p214)
358 static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)
362 static const int bw_tab[] = { 0, 1610612736, 1932735283, 2104533975 };
365 for (i = 0; i < sbr->n_q; i++) {
366 if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1)
369 new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];
371 if (new_bw < ch_data->bw_array[i]){
372 accu = (int64_t)new_bw * 1610612736;
373 accu += (int64_t)ch_data->bw_array[i] * 0x20000000;
374 new_bw = (int)((accu + 0x40000000) >> 31);
376 accu = (int64_t)new_bw * 1946157056;
377 accu += (int64_t)ch_data->bw_array[i] * 201326592;
378 new_bw = (int)((accu + 0x40000000) >> 31);
380 ch_data->bw_array[i] = new_bw < 0x2000000 ? 0 : new_bw;
385 * Calculation of levels of additional HF signal components (14496-3 sp04 p219)
386 * and Calculation of gain (14496-3 sp04 p219)
388 static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,
389 SBRData *ch_data, const int e_a[2])
392 // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)
393 static const SoftFloat limgain[4] = { { 760155524, 0 }, { 0x20000000, 1 },
394 { 758351638, 1 }, { 625000000, 34 } };
396 for (e = 0; e < ch_data->bs_num_env; e++) {
397 int delta = !((e == e_a[1]) || (e == e_a[0]));
398 for (k = 0; k < sbr->n_lim; k++) {
399 SoftFloat gain_boost, gain_max;
400 SoftFloat sum[2] = { { 0, 0}, { 0, 0 } };
401 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
402 const SoftFloat temp = av_div_sf(sbr->e_origmapped[e][m],
403 av_add_sf(FLOAT_1, sbr->q_mapped[e][m]));
404 sbr->q_m[e][m] = av_sqrt_sf(av_mul_sf(temp, sbr->q_mapped[e][m]));
405 sbr->s_m[e][m] = av_sqrt_sf(av_mul_sf(temp, av_int2sf(ch_data->s_indexmapped[e + 1][m], 0)));
406 if (!sbr->s_mapped[e][m]) {
408 sbr->gain[e][m] = av_sqrt_sf(av_div_sf(sbr->e_origmapped[e][m],
409 av_mul_sf(av_add_sf(FLOAT_1, sbr->e_curr[e][m]),
410 av_add_sf(FLOAT_1, sbr->q_mapped[e][m]))));
412 sbr->gain[e][m] = av_sqrt_sf(av_div_sf(sbr->e_origmapped[e][m],
413 av_add_sf(FLOAT_1, sbr->e_curr[e][m])));
416 sbr->gain[e][m] = av_sqrt_sf(
418 av_mul_sf(sbr->e_origmapped[e][m], sbr->q_mapped[e][m]),
420 av_add_sf(FLOAT_1, sbr->e_curr[e][m]),
421 av_add_sf(FLOAT_1, sbr->q_mapped[e][m]))));
424 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
425 sum[0] = av_add_sf(sum[0], sbr->e_origmapped[e][m]);
426 sum[1] = av_add_sf(sum[1], sbr->e_curr[e][m]);
428 gain_max = av_mul_sf(limgain[sbr->bs_limiter_gains],
431 av_add_sf(FLOAT_EPSILON, sum[0]),
432 av_add_sf(FLOAT_EPSILON, sum[1]))));
433 if (av_gt_sf(gain_max, FLOAT_100000))
434 gain_max = FLOAT_100000;
435 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
436 SoftFloat q_m_max = av_div_sf(
437 av_mul_sf(sbr->q_m[e][m], gain_max),
439 if (av_gt_sf(sbr->q_m[e][m], q_m_max))
440 sbr->q_m[e][m] = q_m_max;
441 if (av_gt_sf(sbr->gain[e][m], gain_max))
442 sbr->gain[e][m] = gain_max;
444 sum[0] = sum[1] = FLOAT_0;
445 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
446 sum[0] = av_add_sf(sum[0], sbr->e_origmapped[e][m]);
447 sum[1] = av_add_sf(sum[1],
449 av_mul_sf(sbr->e_curr[e][m],
452 sum[1] = av_add_sf(sum[1],
453 av_mul_sf(sbr->s_m[e][m], sbr->s_m[e][m]));
454 if (delta && !sbr->s_m[e][m].mant)
455 sum[1] = av_add_sf(sum[1],
456 av_mul_sf(sbr->q_m[e][m], sbr->q_m[e][m]));
458 gain_boost = av_sqrt_sf(
460 av_add_sf(FLOAT_EPSILON, sum[0]),
461 av_add_sf(FLOAT_EPSILON, sum[1])));
462 if (av_gt_sf(gain_boost, FLOAT_1584893192))
463 gain_boost = FLOAT_1584893192;
465 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
466 sbr->gain[e][m] = av_mul_sf(sbr->gain[e][m], gain_boost);
467 sbr->q_m[e][m] = av_mul_sf(sbr->q_m[e][m], gain_boost);
468 sbr->s_m[e][m] = av_mul_sf(sbr->s_m[e][m], gain_boost);
474 /// Assembling HF Signals (14496-3 sp04 p220)
475 static void sbr_hf_assemble(int Y1[38][64][2],
476 const int X_high[64][40][2],
477 SpectralBandReplication *sbr, SBRData *ch_data,
481 const int h_SL = 4 * !sbr->bs_smoothing_mode;
482 const int kx = sbr->kx[1];
483 const int m_max = sbr->m[1];
484 static const SoftFloat h_smooth[5] = {
491 SoftFloat (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;
492 int indexnoise = ch_data->f_indexnoise;
493 int indexsine = ch_data->f_indexsine;
496 for (i = 0; i < h_SL; i++) {
497 memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));
498 memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0], m_max * sizeof(sbr->q_m[0][0]));
501 for (i = 0; i < 4; i++) {
502 memcpy(g_temp[i + 2 * ch_data->t_env[0]],
503 g_temp[i + 2 * ch_data->t_env_num_env_old],
505 memcpy(q_temp[i + 2 * ch_data->t_env[0]],
506 q_temp[i + 2 * ch_data->t_env_num_env_old],
511 for (e = 0; e < ch_data->bs_num_env; e++) {
512 for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {
513 memcpy(g_temp[h_SL + i], sbr->gain[e], m_max * sizeof(sbr->gain[0][0]));
514 memcpy(q_temp[h_SL + i], sbr->q_m[e], m_max * sizeof(sbr->q_m[0][0]));
518 for (e = 0; e < ch_data->bs_num_env; e++) {
519 for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {
520 SoftFloat g_filt_tab[48];
521 SoftFloat q_filt_tab[48];
522 SoftFloat *g_filt, *q_filt;
524 if (h_SL && e != e_a[0] && e != e_a[1]) {
527 for (m = 0; m < m_max; m++) {
528 const int idx1 = i + h_SL;
529 g_filt[m].mant = g_filt[m].exp = 0;
530 q_filt[m].mant = q_filt[m].exp = 0;
531 for (j = 0; j <= h_SL; j++) {
532 g_filt[m] = av_add_sf(g_filt[m],
533 av_mul_sf(g_temp[idx1 - j][m],
535 q_filt[m] = av_add_sf(q_filt[m],
536 av_mul_sf(q_temp[idx1 - j][m],
541 g_filt = g_temp[i + h_SL];
545 sbr->dsp.hf_g_filt(Y1[i] + kx, X_high + kx, g_filt, m_max,
546 i + ENVELOPE_ADJUSTMENT_OFFSET);
548 if (e != e_a[0] && e != e_a[1]) {
549 sbr->dsp.hf_apply_noise[indexsine](Y1[i] + kx, sbr->s_m[e],
553 int idx = indexsine&1;
554 int A = (1-((indexsine+(kx & 1))&2));
555 int B = (A^(-idx)) + idx;
556 int *out = &Y1[i][kx][idx];
559 SoftFloat *in = sbr->s_m[e];
560 for (m = 0; m+1 < m_max; m+=2) {
561 shift = 22 - in[m ].exp;
562 round = 1 << (shift-1);
563 out[2*m ] += (in[m ].mant * A + round) >> shift;
565 shift = 22 - in[m+1].exp;
566 round = 1 << (shift-1);
567 out[2*m+2] += (in[m+1].mant * B + round) >> shift;
571 shift = 22 - in[m ].exp;
572 round = 1 << (shift-1);
574 out[2*m ] += (in[m ].mant * A + round) >> shift;
577 indexnoise = (indexnoise + m_max) & 0x1ff;
578 indexsine = (indexsine + 1) & 3;
581 ch_data->f_indexnoise = indexnoise;
582 ch_data->f_indexsine = indexsine;
585 #include "aacsbr_template.c"