2 * AAC Spectral Band Replication decoding functions
3 * Copyright (c) 2008-2009 Robert Swain ( rob opendot cl )
4 * Copyright (c) 2009-2010 Alex Converse <alex.converse@gmail.com>
6 * This file is part of FFmpeg.
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25 * AAC Spectral Band Replication decoding functions
26 * @author Robert Swain ( rob opendot cl )
32 #include "aacsbrdata.h"
33 #include "aacsbr_tablegen.h"
37 #include "libavutil/internal.h"
38 #include "libavutil/libm.h"
39 #include "libavutil/avassert.h"
46 #include "mips/aacsbr_mips.h"
47 #endif /* ARCH_MIPS */
49 static VLC vlc_sbr[10];
50 static void aacsbr_func_ptr_init(AACSBRContext *c);
52 static void make_bands(int16_t* bands, int start, int stop, int num_bands)
54 int k, previous, present;
57 base = powf((float)stop / start, 1.0f / num_bands);
61 for (k = 0; k < num_bands-1; k++) {
63 present = lrintf(prod);
64 bands[k] = present - previous;
67 bands[num_bands-1] = stop - previous;
70 /// Dequantization and stereo decoding (14496-3 sp04 p203)
71 static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)
76 if (id_aac == TYPE_CPE && sbr->bs_coupling) {
77 float alpha = sbr->data[0].bs_amp_res ? 1.0f : 0.5f;
78 float pan_offset = sbr->data[0].bs_amp_res ? 12.0f : 24.0f;
79 for (e = 1; e <= sbr->data[0].bs_num_env; e++) {
80 for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {
81 float temp1 = exp2f(sbr->data[0].env_facs[e][k] * alpha + 7.0f);
82 float temp2 = exp2f((pan_offset - sbr->data[1].env_facs[e][k]) * alpha);
85 av_log(NULL, AV_LOG_ERROR, "envelope scalefactor overflow in dequant\n");
88 fac = temp1 / (1.0f + temp2);
89 sbr->data[0].env_facs[e][k] = fac;
90 sbr->data[1].env_facs[e][k] = fac * temp2;
93 for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {
94 for (k = 0; k < sbr->n_q; k++) {
95 float temp1 = exp2f(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs[e][k] + 1);
96 float temp2 = exp2f(12 - sbr->data[1].noise_facs[e][k]);
99 av_log(NULL, AV_LOG_ERROR, "envelope scalefactor overflow in dequant\n");
102 fac = temp1 / (1.0f + temp2);
103 sbr->data[0].noise_facs[e][k] = fac;
104 sbr->data[1].noise_facs[e][k] = fac * temp2;
107 } else { // SCE or one non-coupled CPE
108 for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {
109 float alpha = sbr->data[ch].bs_amp_res ? 1.0f : 0.5f;
110 for (e = 1; e <= sbr->data[ch].bs_num_env; e++)
111 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++){
112 sbr->data[ch].env_facs[e][k] =
113 exp2f(alpha * sbr->data[ch].env_facs[e][k] + 6.0f);
114 if (sbr->data[ch].env_facs[e][k] > 1E20) {
115 av_log(NULL, AV_LOG_ERROR, "envelope scalefactor overflow in dequant\n");
116 sbr->data[ch].env_facs[e][k] = 1;
120 for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)
121 for (k = 0; k < sbr->n_q; k++)
122 sbr->data[ch].noise_facs[e][k] =
123 exp2f(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs[e][k]);
128 /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering
129 * (14496-3 sp04 p214)
130 * Warning: This routine does not seem numerically stable.
132 static void sbr_hf_inverse_filter(SBRDSPContext *dsp,
133 float (*alpha0)[2], float (*alpha1)[2],
134 const float X_low[32][40][2], int k0)
137 for (k = 0; k < k0; k++) {
138 LOCAL_ALIGNED_16(float, phi, [3], [2][2]);
141 dsp->autocorrelate(X_low[k], phi);
143 dk = phi[2][1][0] * phi[1][0][0] -
144 (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;
150 float temp_real, temp_im;
151 temp_real = phi[0][0][0] * phi[1][1][0] -
152 phi[0][0][1] * phi[1][1][1] -
153 phi[0][1][0] * phi[1][0][0];
154 temp_im = phi[0][0][0] * phi[1][1][1] +
155 phi[0][0][1] * phi[1][1][0] -
156 phi[0][1][1] * phi[1][0][0];
158 alpha1[k][0] = temp_real / dk;
159 alpha1[k][1] = temp_im / dk;
166 float temp_real, temp_im;
167 temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +
168 alpha1[k][1] * phi[1][1][1];
169 temp_im = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -
170 alpha1[k][0] * phi[1][1][1];
172 alpha0[k][0] = -temp_real / phi[1][0][0];
173 alpha0[k][1] = -temp_im / phi[1][0][0];
176 if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||
177 alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {
186 /// Chirp Factors (14496-3 sp04 p214)
187 static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)
191 static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };
193 for (i = 0; i < sbr->n_q; i++) {
194 if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {
197 new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];
199 if (new_bw < ch_data->bw_array[i]) {
200 new_bw = 0.75f * new_bw + 0.25f * ch_data->bw_array[i];
202 new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];
203 ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;
208 * Calculation of levels of additional HF signal components (14496-3 sp04 p219)
209 * and Calculation of gain (14496-3 sp04 p219)
211 static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,
212 SBRData *ch_data, const int e_a[2])
215 // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)
216 static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };
218 for (e = 0; e < ch_data->bs_num_env; e++) {
219 int delta = !((e == e_a[1]) || (e == e_a[0]));
220 for (k = 0; k < sbr->n_lim; k++) {
221 float gain_boost, gain_max;
222 float sum[2] = { 0.0f, 0.0f };
223 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
224 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);
225 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);
226 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);
227 if (!sbr->s_mapped[e][m]) {
228 sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /
229 ((1.0f + sbr->e_curr[e][m]) *
230 (1.0f + sbr->q_mapped[e][m] * delta)));
232 sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /
233 ((1.0f + sbr->e_curr[e][m]) *
234 (1.0f + sbr->q_mapped[e][m])));
237 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
238 sum[0] += sbr->e_origmapped[e][m];
239 sum[1] += sbr->e_curr[e][m];
241 gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));
242 gain_max = FFMIN(100000.f, gain_max);
243 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
244 float q_m_max = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];
245 sbr->q_m[e][m] = FFMIN(sbr->q_m[e][m], q_m_max);
246 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);
248 sum[0] = sum[1] = 0.0f;
249 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
250 sum[0] += sbr->e_origmapped[e][m];
251 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]
252 + sbr->s_m[e][m] * sbr->s_m[e][m]
253 + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];
255 gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));
256 gain_boost = FFMIN(1.584893192f, gain_boost);
257 for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
258 sbr->gain[e][m] *= gain_boost;
259 sbr->q_m[e][m] *= gain_boost;
260 sbr->s_m[e][m] *= gain_boost;
266 /// Assembling HF Signals (14496-3 sp04 p220)
267 static void sbr_hf_assemble(float Y1[38][64][2],
268 const float X_high[64][40][2],
269 SpectralBandReplication *sbr, SBRData *ch_data,
273 const int h_SL = 4 * !sbr->bs_smoothing_mode;
274 const int kx = sbr->kx[1];
275 const int m_max = sbr->m[1];
276 static const float h_smooth[5] = {
283 float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;
284 int indexnoise = ch_data->f_indexnoise;
285 int indexsine = ch_data->f_indexsine;
288 for (i = 0; i < h_SL; i++) {
289 memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));
290 memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0], m_max * sizeof(sbr->q_m[0][0]));
293 for (i = 0; i < 4; i++) {
294 memcpy(g_temp[i + 2 * ch_data->t_env[0]],
295 g_temp[i + 2 * ch_data->t_env_num_env_old],
297 memcpy(q_temp[i + 2 * ch_data->t_env[0]],
298 q_temp[i + 2 * ch_data->t_env_num_env_old],
303 for (e = 0; e < ch_data->bs_num_env; e++) {
304 for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {
305 memcpy(g_temp[h_SL + i], sbr->gain[e], m_max * sizeof(sbr->gain[0][0]));
306 memcpy(q_temp[h_SL + i], sbr->q_m[e], m_max * sizeof(sbr->q_m[0][0]));
310 for (e = 0; e < ch_data->bs_num_env; e++) {
311 for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {
312 LOCAL_ALIGNED_16(float, g_filt_tab, [48]);
313 LOCAL_ALIGNED_16(float, q_filt_tab, [48]);
314 float *g_filt, *q_filt;
316 if (h_SL && e != e_a[0] && e != e_a[1]) {
319 for (m = 0; m < m_max; m++) {
320 const int idx1 = i + h_SL;
323 for (j = 0; j <= h_SL; j++) {
324 g_filt[m] += g_temp[idx1 - j][m] * h_smooth[j];
325 q_filt[m] += q_temp[idx1 - j][m] * h_smooth[j];
329 g_filt = g_temp[i + h_SL];
333 sbr->dsp.hf_g_filt(Y1[i] + kx, X_high + kx, g_filt, m_max,
334 i + ENVELOPE_ADJUSTMENT_OFFSET);
336 if (e != e_a[0] && e != e_a[1]) {
337 sbr->dsp.hf_apply_noise[indexsine](Y1[i] + kx, sbr->s_m[e],
341 int idx = indexsine&1;
342 int A = (1-((indexsine+(kx & 1))&2));
343 int B = (A^(-idx)) + idx;
344 float *out = &Y1[i][kx][idx];
345 float *in = sbr->s_m[e];
346 for (m = 0; m+1 < m_max; m+=2) {
347 out[2*m ] += in[m ] * A;
348 out[2*m+2] += in[m+1] * B;
351 out[2*m ] += in[m ] * A;
353 indexnoise = (indexnoise + m_max) & 0x1ff;
354 indexsine = (indexsine + 1) & 3;
357 ch_data->f_indexnoise = indexnoise;
358 ch_data->f_indexsine = indexsine;
361 #include "aacsbr_template.c"