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1 | /* |
2 | * QCELP decoder | |
3 | * Copyright (c) 2007 Reynaldo H. Verdejo Pinochet | |
4 | * | |
5 | * This file is part of FFmpeg. | |
6 | * | |
7 | * FFmpeg is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU Lesser General Public | |
9 | * License as published by the Free Software Foundation; either | |
10 | * version 2.1 of the License, or (at your option) any later version. | |
11 | * | |
12 | * FFmpeg is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * Lesser General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public | |
18 | * License along with FFmpeg; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
22 | /** | |
23 | * @file | |
24 | * QCELP decoder | |
25 | * @author Reynaldo H. Verdejo Pinochet | |
26 | * @remark FFmpeg merging spearheaded by Kenan Gillet | |
27 | * @remark Development mentored by Benjamin Larson | |
28 | */ | |
29 | ||
30 | #include <stddef.h> | |
31 | ||
32 | #include "libavutil/avassert.h" | |
33 | #include "libavutil/channel_layout.h" | |
34 | #include "libavutil/float_dsp.h" | |
35 | #include "avcodec.h" | |
36 | #include "internal.h" | |
37 | #include "get_bits.h" | |
38 | #include "qcelpdata.h" | |
39 | #include "celp_filters.h" | |
40 | #include "acelp_filters.h" | |
41 | #include "acelp_vectors.h" | |
42 | #include "lsp.h" | |
43 | ||
44 | typedef enum { | |
45 | I_F_Q = -1, /**< insufficient frame quality */ | |
46 | SILENCE, | |
47 | RATE_OCTAVE, | |
48 | RATE_QUARTER, | |
49 | RATE_HALF, | |
50 | RATE_FULL | |
51 | } qcelp_packet_rate; | |
52 | ||
53 | typedef struct { | |
54 | GetBitContext gb; | |
55 | qcelp_packet_rate bitrate; | |
56 | QCELPFrame frame; /**< unpacked data frame */ | |
57 | ||
58 | uint8_t erasure_count; | |
59 | uint8_t octave_count; /**< count the consecutive RATE_OCTAVE frames */ | |
60 | float prev_lspf[10]; | |
61 | float predictor_lspf[10];/**< LSP predictor for RATE_OCTAVE and I_F_Q */ | |
62 | float pitch_synthesis_filter_mem[303]; | |
63 | float pitch_pre_filter_mem[303]; | |
64 | float rnd_fir_filter_mem[180]; | |
65 | float formant_mem[170]; | |
66 | float last_codebook_gain; | |
67 | int prev_g1[2]; | |
68 | int prev_bitrate; | |
69 | float pitch_gain[4]; | |
70 | uint8_t pitch_lag[4]; | |
71 | uint16_t first16bits; | |
72 | uint8_t warned_buf_mismatch_bitrate; | |
73 | ||
74 | /* postfilter */ | |
75 | float postfilter_synth_mem[10]; | |
76 | float postfilter_agc_mem; | |
77 | float postfilter_tilt_mem; | |
78 | } QCELPContext; | |
79 | ||
80 | /** | |
81 | * Initialize the speech codec according to the specification. | |
82 | * | |
83 | * TIA/EIA/IS-733 2.4.9 | |
84 | */ | |
85 | static av_cold int qcelp_decode_init(AVCodecContext *avctx) | |
86 | { | |
87 | QCELPContext *q = avctx->priv_data; | |
88 | int i; | |
89 | ||
90 | avctx->channels = 1; | |
91 | avctx->channel_layout = AV_CH_LAYOUT_MONO; | |
92 | avctx->sample_fmt = AV_SAMPLE_FMT_FLT; | |
93 | ||
94 | for (i = 0; i < 10; i++) | |
95 | q->prev_lspf[i] = (i + 1) / 11.0; | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | /** | |
101 | * Decode the 10 quantized LSP frequencies from the LSPV/LSP | |
102 | * transmission codes of any bitrate and check for badly received packets. | |
103 | * | |
104 | * @param q the context | |
105 | * @param lspf line spectral pair frequencies | |
106 | * | |
107 | * @return 0 on success, -1 if the packet is badly received | |
108 | * | |
109 | * TIA/EIA/IS-733 2.4.3.2.6.2-2, 2.4.8.7.3 | |
110 | */ | |
111 | static int decode_lspf(QCELPContext *q, float *lspf) | |
112 | { | |
113 | int i; | |
114 | float tmp_lspf, smooth, erasure_coeff; | |
115 | const float *predictors; | |
116 | ||
117 | if (q->bitrate == RATE_OCTAVE || q->bitrate == I_F_Q) { | |
118 | predictors = q->prev_bitrate != RATE_OCTAVE && | |
119 | q->prev_bitrate != I_F_Q ? q->prev_lspf | |
120 | : q->predictor_lspf; | |
121 | ||
122 | if (q->bitrate == RATE_OCTAVE) { | |
123 | q->octave_count++; | |
124 | ||
125 | for (i = 0; i < 10; i++) { | |
126 | q->predictor_lspf[i] = | |
127 | lspf[i] = (q->frame.lspv[i] ? QCELP_LSP_SPREAD_FACTOR | |
128 | : -QCELP_LSP_SPREAD_FACTOR) + | |
129 | predictors[i] * QCELP_LSP_OCTAVE_PREDICTOR + | |
130 | (i + 1) * ((1 - QCELP_LSP_OCTAVE_PREDICTOR) / 11); | |
131 | } | |
132 | smooth = q->octave_count < 10 ? .875 : 0.1; | |
133 | } else { | |
134 | erasure_coeff = QCELP_LSP_OCTAVE_PREDICTOR; | |
135 | ||
136 | av_assert2(q->bitrate == I_F_Q); | |
137 | ||
138 | if (q->erasure_count > 1) | |
139 | erasure_coeff *= q->erasure_count < 4 ? 0.9 : 0.7; | |
140 | ||
141 | for (i = 0; i < 10; i++) { | |
142 | q->predictor_lspf[i] = | |
143 | lspf[i] = (i + 1) * (1 - erasure_coeff) / 11 + | |
144 | erasure_coeff * predictors[i]; | |
145 | } | |
146 | smooth = 0.125; | |
147 | } | |
148 | ||
149 | // Check the stability of the LSP frequencies. | |
150 | lspf[0] = FFMAX(lspf[0], QCELP_LSP_SPREAD_FACTOR); | |
151 | for (i = 1; i < 10; i++) | |
152 | lspf[i] = FFMAX(lspf[i], lspf[i - 1] + QCELP_LSP_SPREAD_FACTOR); | |
153 | ||
154 | lspf[9] = FFMIN(lspf[9], 1.0 - QCELP_LSP_SPREAD_FACTOR); | |
155 | for (i = 9; i > 0; i--) | |
156 | lspf[i - 1] = FFMIN(lspf[i - 1], lspf[i] - QCELP_LSP_SPREAD_FACTOR); | |
157 | ||
158 | // Low-pass filter the LSP frequencies. | |
159 | ff_weighted_vector_sumf(lspf, lspf, q->prev_lspf, smooth, 1.0 - smooth, 10); | |
160 | } else { | |
161 | q->octave_count = 0; | |
162 | ||
163 | tmp_lspf = 0.0; | |
164 | for (i = 0; i < 5; i++) { | |
165 | lspf[2 * i + 0] = tmp_lspf += qcelp_lspvq[i][q->frame.lspv[i]][0] * 0.0001; | |
166 | lspf[2 * i + 1] = tmp_lspf += qcelp_lspvq[i][q->frame.lspv[i]][1] * 0.0001; | |
167 | } | |
168 | ||
169 | // Check for badly received packets. | |
170 | if (q->bitrate == RATE_QUARTER) { | |
171 | if (lspf[9] <= .70 || lspf[9] >= .97) | |
172 | return -1; | |
173 | for (i = 3; i < 10; i++) | |
174 | if (fabs(lspf[i] - lspf[i - 2]) < .08) | |
175 | return -1; | |
176 | } else { | |
177 | if (lspf[9] <= .66 || lspf[9] >= .985) | |
178 | return -1; | |
179 | for (i = 4; i < 10; i++) | |
180 | if (fabs(lspf[i] - lspf[i - 4]) < .0931) | |
181 | return -1; | |
182 | } | |
183 | } | |
184 | return 0; | |
185 | } | |
186 | ||
187 | /** | |
188 | * Convert codebook transmission codes to GAIN and INDEX. | |
189 | * | |
190 | * @param q the context | |
191 | * @param gain array holding the decoded gain | |
192 | * | |
193 | * TIA/EIA/IS-733 2.4.6.2 | |
194 | */ | |
195 | static void decode_gain_and_index(QCELPContext *q, float *gain) | |
196 | { | |
197 | int i, subframes_count, g1[16]; | |
198 | float slope; | |
199 | ||
200 | if (q->bitrate >= RATE_QUARTER) { | |
201 | switch (q->bitrate) { | |
202 | case RATE_FULL: subframes_count = 16; break; | |
203 | case RATE_HALF: subframes_count = 4; break; | |
204 | default: subframes_count = 5; | |
205 | } | |
206 | for (i = 0; i < subframes_count; i++) { | |
207 | g1[i] = 4 * q->frame.cbgain[i]; | |
208 | if (q->bitrate == RATE_FULL && !((i + 1) & 3)) { | |
209 | g1[i] += av_clip((g1[i - 1] + g1[i - 2] + g1[i - 3]) / 3 - 6, 0, 32); | |
210 | } | |
211 | ||
212 | gain[i] = qcelp_g12ga[g1[i]]; | |
213 | ||
214 | if (q->frame.cbsign[i]) { | |
215 | gain[i] = -gain[i]; | |
216 | q->frame.cindex[i] = (q->frame.cindex[i] - 89) & 127; | |
217 | } | |
218 | } | |
219 | ||
220 | q->prev_g1[0] = g1[i - 2]; | |
221 | q->prev_g1[1] = g1[i - 1]; | |
222 | q->last_codebook_gain = qcelp_g12ga[g1[i - 1]]; | |
223 | ||
224 | if (q->bitrate == RATE_QUARTER) { | |
225 | // Provide smoothing of the unvoiced excitation energy. | |
226 | gain[7] = gain[4]; | |
227 | gain[6] = 0.4 * gain[3] + 0.6 * gain[4]; | |
228 | gain[5] = gain[3]; | |
229 | gain[4] = 0.8 * gain[2] + 0.2 * gain[3]; | |
230 | gain[3] = 0.2 * gain[1] + 0.8 * gain[2]; | |
231 | gain[2] = gain[1]; | |
232 | gain[1] = 0.6 * gain[0] + 0.4 * gain[1]; | |
233 | } | |
234 | } else if (q->bitrate != SILENCE) { | |
235 | if (q->bitrate == RATE_OCTAVE) { | |
236 | g1[0] = 2 * q->frame.cbgain[0] + | |
237 | av_clip((q->prev_g1[0] + q->prev_g1[1]) / 2 - 5, 0, 54); | |
238 | subframes_count = 8; | |
239 | } else { | |
240 | av_assert2(q->bitrate == I_F_Q); | |
241 | ||
242 | g1[0] = q->prev_g1[1]; | |
243 | switch (q->erasure_count) { | |
244 | case 1 : break; | |
245 | case 2 : g1[0] -= 1; break; | |
246 | case 3 : g1[0] -= 2; break; | |
247 | default: g1[0] -= 6; | |
248 | } | |
249 | if (g1[0] < 0) | |
250 | g1[0] = 0; | |
251 | subframes_count = 4; | |
252 | } | |
253 | // This interpolation is done to produce smoother background noise. | |
254 | slope = 0.5 * (qcelp_g12ga[g1[0]] - q->last_codebook_gain) / subframes_count; | |
255 | for (i = 1; i <= subframes_count; i++) | |
256 | gain[i - 1] = q->last_codebook_gain + slope * i; | |
257 | ||
258 | q->last_codebook_gain = gain[i - 2]; | |
259 | q->prev_g1[0] = q->prev_g1[1]; | |
260 | q->prev_g1[1] = g1[0]; | |
261 | } | |
262 | } | |
263 | ||
264 | /** | |
265 | * If the received packet is Rate 1/4 a further sanity check is made of the | |
266 | * codebook gain. | |
267 | * | |
268 | * @param cbgain the unpacked cbgain array | |
269 | * @return -1 if the sanity check fails, 0 otherwise | |
270 | * | |
271 | * TIA/EIA/IS-733 2.4.8.7.3 | |
272 | */ | |
273 | static int codebook_sanity_check_for_rate_quarter(const uint8_t *cbgain) | |
274 | { | |
275 | int i, diff, prev_diff = 0; | |
276 | ||
277 | for (i = 1; i < 5; i++) { | |
278 | diff = cbgain[i] - cbgain[i-1]; | |
279 | if (FFABS(diff) > 10) | |
280 | return -1; | |
281 | else if (FFABS(diff - prev_diff) > 12) | |
282 | return -1; | |
283 | prev_diff = diff; | |
284 | } | |
285 | return 0; | |
286 | } | |
287 | ||
288 | /** | |
289 | * Compute the scaled codebook vector Cdn From INDEX and GAIN | |
290 | * for all rates. | |
291 | * | |
292 | * The specification lacks some information here. | |
293 | * | |
294 | * TIA/EIA/IS-733 has an omission on the codebook index determination | |
295 | * formula for RATE_FULL and RATE_HALF frames at section 2.4.8.1.1. It says | |
296 | * you have to subtract the decoded index parameter from the given scaled | |
297 | * codebook vector index 'n' to get the desired circular codebook index, but | |
298 | * it does not mention that you have to clamp 'n' to [0-9] in order to get | |
299 | * RI-compliant results. | |
300 | * | |
301 | * The reason for this mistake seems to be the fact they forgot to mention you | |
302 | * have to do these calculations per codebook subframe and adjust given | |
303 | * equation values accordingly. | |
304 | * | |
305 | * @param q the context | |
306 | * @param gain array holding the 4 pitch subframe gain values | |
307 | * @param cdn_vector array for the generated scaled codebook vector | |
308 | */ | |
309 | static void compute_svector(QCELPContext *q, const float *gain, | |
310 | float *cdn_vector) | |
311 | { | |
312 | int i, j, k; | |
313 | uint16_t cbseed, cindex; | |
314 | float *rnd, tmp_gain, fir_filter_value; | |
315 | ||
316 | switch (q->bitrate) { | |
317 | case RATE_FULL: | |
318 | for (i = 0; i < 16; i++) { | |
319 | tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO; | |
320 | cindex = -q->frame.cindex[i]; | |
321 | for (j = 0; j < 10; j++) | |
322 | *cdn_vector++ = tmp_gain * | |
323 | qcelp_rate_full_codebook[cindex++ & 127]; | |
324 | } | |
325 | break; | |
326 | case RATE_HALF: | |
327 | for (i = 0; i < 4; i++) { | |
328 | tmp_gain = gain[i] * QCELP_RATE_HALF_CODEBOOK_RATIO; | |
329 | cindex = -q->frame.cindex[i]; | |
330 | for (j = 0; j < 40; j++) | |
331 | *cdn_vector++ = tmp_gain * | |
332 | qcelp_rate_half_codebook[cindex++ & 127]; | |
333 | } | |
334 | break; | |
335 | case RATE_QUARTER: | |
336 | cbseed = (0x0003 & q->frame.lspv[4]) << 14 | | |
337 | (0x003F & q->frame.lspv[3]) << 8 | | |
338 | (0x0060 & q->frame.lspv[2]) << 1 | | |
339 | (0x0007 & q->frame.lspv[1]) << 3 | | |
340 | (0x0038 & q->frame.lspv[0]) >> 3; | |
341 | rnd = q->rnd_fir_filter_mem + 20; | |
342 | for (i = 0; i < 8; i++) { | |
343 | tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0); | |
344 | for (k = 0; k < 20; k++) { | |
345 | cbseed = 521 * cbseed + 259; | |
346 | *rnd = (int16_t) cbseed; | |
347 | ||
348 | // FIR filter | |
349 | fir_filter_value = 0.0; | |
350 | for (j = 0; j < 10; j++) | |
351 | fir_filter_value += qcelp_rnd_fir_coefs[j] * | |
352 | (rnd[-j] + rnd[-20+j]); | |
353 | ||
354 | fir_filter_value += qcelp_rnd_fir_coefs[10] * rnd[-10]; | |
355 | *cdn_vector++ = tmp_gain * fir_filter_value; | |
356 | rnd++; | |
357 | } | |
358 | } | |
359 | memcpy(q->rnd_fir_filter_mem, q->rnd_fir_filter_mem + 160, | |
360 | 20 * sizeof(float)); | |
361 | break; | |
362 | case RATE_OCTAVE: | |
363 | cbseed = q->first16bits; | |
364 | for (i = 0; i < 8; i++) { | |
365 | tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0); | |
366 | for (j = 0; j < 20; j++) { | |
367 | cbseed = 521 * cbseed + 259; | |
368 | *cdn_vector++ = tmp_gain * (int16_t) cbseed; | |
369 | } | |
370 | } | |
371 | break; | |
372 | case I_F_Q: | |
373 | cbseed = -44; // random codebook index | |
374 | for (i = 0; i < 4; i++) { | |
375 | tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO; | |
376 | for (j = 0; j < 40; j++) | |
377 | *cdn_vector++ = tmp_gain * | |
378 | qcelp_rate_full_codebook[cbseed++ & 127]; | |
379 | } | |
380 | break; | |
381 | case SILENCE: | |
382 | memset(cdn_vector, 0, 160 * sizeof(float)); | |
383 | break; | |
384 | } | |
385 | } | |
386 | ||
387 | /** | |
388 | * Apply generic gain control. | |
389 | * | |
390 | * @param v_out output vector | |
391 | * @param v_in gain-controlled vector | |
392 | * @param v_ref vector to control gain of | |
393 | * | |
394 | * TIA/EIA/IS-733 2.4.8.3, 2.4.8.6 | |
395 | */ | |
396 | static void apply_gain_ctrl(float *v_out, const float *v_ref, const float *v_in) | |
397 | { | |
398 | int i; | |
399 | ||
400 | for (i = 0; i < 160; i += 40) { | |
401 | float res = avpriv_scalarproduct_float_c(v_ref + i, v_ref + i, 40); | |
402 | ff_scale_vector_to_given_sum_of_squares(v_out + i, v_in + i, res, 40); | |
403 | } | |
404 | } | |
405 | ||
406 | /** | |
407 | * Apply filter in pitch-subframe steps. | |
408 | * | |
409 | * @param memory buffer for the previous state of the filter | |
410 | * - must be able to contain 303 elements | |
411 | * - the 143 first elements are from the previous state | |
412 | * - the next 160 are for output | |
413 | * @param v_in input filter vector | |
414 | * @param gain per-subframe gain array, each element is between 0.0 and 2.0 | |
415 | * @param lag per-subframe lag array, each element is | |
416 | * - between 16 and 143 if its corresponding pfrac is 0, | |
417 | * - between 16 and 139 otherwise | |
418 | * @param pfrac per-subframe boolean array, 1 if the lag is fractional, 0 | |
419 | * otherwise | |
420 | * | |
421 | * @return filter output vector | |
422 | */ | |
423 | static const float *do_pitchfilter(float memory[303], const float v_in[160], | |
424 | const float gain[4], const uint8_t *lag, | |
425 | const uint8_t pfrac[4]) | |
426 | { | |
427 | int i, j; | |
428 | float *v_lag, *v_out; | |
429 | const float *v_len; | |
430 | ||
431 | v_out = memory + 143; // Output vector starts at memory[143]. | |
432 | ||
433 | for (i = 0; i < 4; i++) { | |
434 | if (gain[i]) { | |
435 | v_lag = memory + 143 + 40 * i - lag[i]; | |
436 | for (v_len = v_in + 40; v_in < v_len; v_in++) { | |
437 | if (pfrac[i]) { // If it is a fractional lag... | |
438 | for (j = 0, *v_out = 0.0; j < 4; j++) | |
439 | *v_out += qcelp_hammsinc_table[j] * | |
440 | (v_lag[j - 4] + v_lag[3 - j]); | |
441 | } else | |
442 | *v_out = *v_lag; | |
443 | ||
444 | *v_out = *v_in + gain[i] * *v_out; | |
445 | ||
446 | v_lag++; | |
447 | v_out++; | |
448 | } | |
449 | } else { | |
450 | memcpy(v_out, v_in, 40 * sizeof(float)); | |
451 | v_in += 40; | |
452 | v_out += 40; | |
453 | } | |
454 | } | |
455 | ||
456 | memmove(memory, memory + 160, 143 * sizeof(float)); | |
457 | return memory + 143; | |
458 | } | |
459 | ||
460 | /** | |
461 | * Apply pitch synthesis filter and pitch prefilter to the scaled codebook vector. | |
462 | * TIA/EIA/IS-733 2.4.5.2, 2.4.8.7.2 | |
463 | * | |
464 | * @param q the context | |
465 | * @param cdn_vector the scaled codebook vector | |
466 | */ | |
467 | static void apply_pitch_filters(QCELPContext *q, float *cdn_vector) | |
468 | { | |
469 | int i; | |
470 | const float *v_synthesis_filtered, *v_pre_filtered; | |
471 | ||
472 | if (q->bitrate >= RATE_HALF || q->bitrate == SILENCE || | |
473 | (q->bitrate == I_F_Q && (q->prev_bitrate >= RATE_HALF))) { | |
474 | ||
475 | if (q->bitrate >= RATE_HALF) { | |
476 | // Compute gain & lag for the whole frame. | |
477 | for (i = 0; i < 4; i++) { | |
478 | q->pitch_gain[i] = q->frame.plag[i] ? (q->frame.pgain[i] + 1) * 0.25 : 0.0; | |
479 | ||
480 | q->pitch_lag[i] = q->frame.plag[i] + 16; | |
481 | } | |
482 | } else { | |
483 | float max_pitch_gain; | |
484 | ||
485 | if (q->bitrate == I_F_Q) { | |
486 | if (q->erasure_count < 3) | |
487 | max_pitch_gain = 0.9 - 0.3 * (q->erasure_count - 1); | |
488 | else | |
489 | max_pitch_gain = 0.0; | |
490 | } else { | |
491 | av_assert2(q->bitrate == SILENCE); | |
492 | max_pitch_gain = 1.0; | |
493 | } | |
494 | for (i = 0; i < 4; i++) | |
495 | q->pitch_gain[i] = FFMIN(q->pitch_gain[i], max_pitch_gain); | |
496 | ||
497 | memset(q->frame.pfrac, 0, sizeof(q->frame.pfrac)); | |
498 | } | |
499 | ||
500 | // pitch synthesis filter | |
501 | v_synthesis_filtered = do_pitchfilter(q->pitch_synthesis_filter_mem, | |
502 | cdn_vector, q->pitch_gain, | |
503 | q->pitch_lag, q->frame.pfrac); | |
504 | ||
505 | // pitch prefilter update | |
506 | for (i = 0; i < 4; i++) | |
507 | q->pitch_gain[i] = 0.5 * FFMIN(q->pitch_gain[i], 1.0); | |
508 | ||
509 | v_pre_filtered = do_pitchfilter(q->pitch_pre_filter_mem, | |
510 | v_synthesis_filtered, | |
511 | q->pitch_gain, q->pitch_lag, | |
512 | q->frame.pfrac); | |
513 | ||
514 | apply_gain_ctrl(cdn_vector, v_synthesis_filtered, v_pre_filtered); | |
515 | } else { | |
516 | memcpy(q->pitch_synthesis_filter_mem, | |
517 | cdn_vector + 17, 143 * sizeof(float)); | |
518 | memcpy(q->pitch_pre_filter_mem, cdn_vector + 17, 143 * sizeof(float)); | |
519 | memset(q->pitch_gain, 0, sizeof(q->pitch_gain)); | |
520 | memset(q->pitch_lag, 0, sizeof(q->pitch_lag)); | |
521 | } | |
522 | } | |
523 | ||
524 | /** | |
525 | * Reconstruct LPC coefficients from the line spectral pair frequencies | |
526 | * and perform bandwidth expansion. | |
527 | * | |
528 | * @param lspf line spectral pair frequencies | |
529 | * @param lpc linear predictive coding coefficients | |
530 | * | |
531 | * @note: bandwidth_expansion_coeff could be precalculated into a table | |
532 | * but it seems to be slower on x86 | |
533 | * | |
534 | * TIA/EIA/IS-733 2.4.3.3.5 | |
535 | */ | |
536 | static void lspf2lpc(const float *lspf, float *lpc) | |
537 | { | |
538 | double lsp[10]; | |
539 | double bandwidth_expansion_coeff = QCELP_BANDWIDTH_EXPANSION_COEFF; | |
540 | int i; | |
541 | ||
542 | for (i = 0; i < 10; i++) | |
543 | lsp[i] = cos(M_PI * lspf[i]); | |
544 | ||
545 | ff_acelp_lspd2lpc(lsp, lpc, 5); | |
546 | ||
547 | for (i = 0; i < 10; i++) { | |
548 | lpc[i] *= bandwidth_expansion_coeff; | |
549 | bandwidth_expansion_coeff *= QCELP_BANDWIDTH_EXPANSION_COEFF; | |
550 | } | |
551 | } | |
552 | ||
553 | /** | |
554 | * Interpolate LSP frequencies and compute LPC coefficients | |
555 | * for a given bitrate & pitch subframe. | |
556 | * | |
557 | * TIA/EIA/IS-733 2.4.3.3.4, 2.4.8.7.2 | |
558 | * | |
559 | * @param q the context | |
560 | * @param curr_lspf LSP frequencies vector of the current frame | |
561 | * @param lpc float vector for the resulting LPC | |
562 | * @param subframe_num frame number in decoded stream | |
563 | */ | |
564 | static void interpolate_lpc(QCELPContext *q, const float *curr_lspf, | |
565 | float *lpc, const int subframe_num) | |
566 | { | |
567 | float interpolated_lspf[10]; | |
568 | float weight; | |
569 | ||
570 | if (q->bitrate >= RATE_QUARTER) | |
571 | weight = 0.25 * (subframe_num + 1); | |
572 | else if (q->bitrate == RATE_OCTAVE && !subframe_num) | |
573 | weight = 0.625; | |
574 | else | |
575 | weight = 1.0; | |
576 | ||
577 | if (weight != 1.0) { | |
578 | ff_weighted_vector_sumf(interpolated_lspf, curr_lspf, q->prev_lspf, | |
579 | weight, 1.0 - weight, 10); | |
580 | lspf2lpc(interpolated_lspf, lpc); | |
581 | } else if (q->bitrate >= RATE_QUARTER || | |
582 | (q->bitrate == I_F_Q && !subframe_num)) | |
583 | lspf2lpc(curr_lspf, lpc); | |
584 | else if (q->bitrate == SILENCE && !subframe_num) | |
585 | lspf2lpc(q->prev_lspf, lpc); | |
586 | } | |
587 | ||
588 | static qcelp_packet_rate buf_size2bitrate(const int buf_size) | |
589 | { | |
590 | switch (buf_size) { | |
591 | case 35: return RATE_FULL; | |
592 | case 17: return RATE_HALF; | |
593 | case 8: return RATE_QUARTER; | |
594 | case 4: return RATE_OCTAVE; | |
595 | case 1: return SILENCE; | |
596 | } | |
597 | ||
598 | return I_F_Q; | |
599 | } | |
600 | ||
601 | /** | |
602 | * Determine the bitrate from the frame size and/or the first byte of the frame. | |
603 | * | |
604 | * @param avctx the AV codec context | |
605 | * @param buf_size length of the buffer | |
606 | * @param buf the bufffer | |
607 | * | |
608 | * @return the bitrate on success, | |
609 | * I_F_Q if the bitrate cannot be satisfactorily determined | |
610 | * | |
611 | * TIA/EIA/IS-733 2.4.8.7.1 | |
612 | */ | |
613 | static qcelp_packet_rate determine_bitrate(AVCodecContext *avctx, | |
614 | const int buf_size, | |
615 | const uint8_t **buf) | |
616 | { | |
617 | qcelp_packet_rate bitrate; | |
618 | ||
619 | if ((bitrate = buf_size2bitrate(buf_size)) >= 0) { | |
620 | if (bitrate > **buf) { | |
621 | QCELPContext *q = avctx->priv_data; | |
622 | if (!q->warned_buf_mismatch_bitrate) { | |
623 | av_log(avctx, AV_LOG_WARNING, | |
624 | "Claimed bitrate and buffer size mismatch.\n"); | |
625 | q->warned_buf_mismatch_bitrate = 1; | |
626 | } | |
627 | bitrate = **buf; | |
628 | } else if (bitrate < **buf) { | |
629 | av_log(avctx, AV_LOG_ERROR, | |
630 | "Buffer is too small for the claimed bitrate.\n"); | |
631 | return I_F_Q; | |
632 | } | |
633 | (*buf)++; | |
634 | } else if ((bitrate = buf_size2bitrate(buf_size + 1)) >= 0) { | |
635 | av_log(avctx, AV_LOG_WARNING, | |
636 | "Bitrate byte missing, guessing bitrate from packet size.\n"); | |
637 | } else | |
638 | return I_F_Q; | |
639 | ||
640 | if (bitrate == SILENCE) { | |
641 | // FIXME: Remove this warning when tested with samples. | |
642 | avpriv_request_sample(avctx, "Blank frame handling"); | |
643 | } | |
644 | return bitrate; | |
645 | } | |
646 | ||
647 | static void warn_insufficient_frame_quality(AVCodecContext *avctx, | |
648 | const char *message) | |
649 | { | |
650 | av_log(avctx, AV_LOG_WARNING, "Frame #%d, IFQ: %s\n", | |
651 | avctx->frame_number, message); | |
652 | } | |
653 | ||
654 | static void postfilter(QCELPContext *q, float *samples, float *lpc) | |
655 | { | |
656 | static const float pow_0_775[10] = { | |
657 | 0.775000, 0.600625, 0.465484, 0.360750, 0.279582, | |
658 | 0.216676, 0.167924, 0.130141, 0.100859, 0.078166 | |
659 | }, pow_0_625[10] = { | |
660 | 0.625000, 0.390625, 0.244141, 0.152588, 0.095367, | |
661 | 0.059605, 0.037253, 0.023283, 0.014552, 0.009095 | |
662 | }; | |
663 | float lpc_s[10], lpc_p[10], pole_out[170], zero_out[160]; | |
664 | int n; | |
665 | ||
666 | for (n = 0; n < 10; n++) { | |
667 | lpc_s[n] = lpc[n] * pow_0_625[n]; | |
668 | lpc_p[n] = lpc[n] * pow_0_775[n]; | |
669 | } | |
670 | ||
671 | ff_celp_lp_zero_synthesis_filterf(zero_out, lpc_s, | |
672 | q->formant_mem + 10, 160, 10); | |
673 | memcpy(pole_out, q->postfilter_synth_mem, sizeof(float) * 10); | |
674 | ff_celp_lp_synthesis_filterf(pole_out + 10, lpc_p, zero_out, 160, 10); | |
675 | memcpy(q->postfilter_synth_mem, pole_out + 160, sizeof(float) * 10); | |
676 | ||
677 | ff_tilt_compensation(&q->postfilter_tilt_mem, 0.3, pole_out + 10, 160); | |
678 | ||
679 | ff_adaptive_gain_control(samples, pole_out + 10, | |
680 | avpriv_scalarproduct_float_c(q->formant_mem + 10, | |
681 | q->formant_mem + 10, | |
682 | 160), | |
683 | 160, 0.9375, &q->postfilter_agc_mem); | |
684 | } | |
685 | ||
686 | static int qcelp_decode_frame(AVCodecContext *avctx, void *data, | |
687 | int *got_frame_ptr, AVPacket *avpkt) | |
688 | { | |
689 | const uint8_t *buf = avpkt->data; | |
690 | int buf_size = avpkt->size; | |
691 | QCELPContext *q = avctx->priv_data; | |
692 | AVFrame *frame = data; | |
693 | float *outbuffer; | |
694 | int i, ret; | |
695 | float quantized_lspf[10], lpc[10]; | |
696 | float gain[16]; | |
697 | float *formant_mem; | |
698 | ||
699 | /* get output buffer */ | |
700 | frame->nb_samples = 160; | |
701 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) | |
702 | return ret; | |
703 | outbuffer = (float *)frame->data[0]; | |
704 | ||
705 | if ((q->bitrate = determine_bitrate(avctx, buf_size, &buf)) == I_F_Q) { | |
706 | warn_insufficient_frame_quality(avctx, "Bitrate cannot be determined."); | |
707 | goto erasure; | |
708 | } | |
709 | ||
710 | if (q->bitrate == RATE_OCTAVE && | |
711 | (q->first16bits = AV_RB16(buf)) == 0xFFFF) { | |
712 | warn_insufficient_frame_quality(avctx, "Bitrate is 1/8 and first 16 bits are on."); | |
713 | goto erasure; | |
714 | } | |
715 | ||
716 | if (q->bitrate > SILENCE) { | |
717 | const QCELPBitmap *bitmaps = qcelp_unpacking_bitmaps_per_rate[q->bitrate]; | |
718 | const QCELPBitmap *bitmaps_end = qcelp_unpacking_bitmaps_per_rate[q->bitrate] + | |
719 | qcelp_unpacking_bitmaps_lengths[q->bitrate]; | |
720 | uint8_t *unpacked_data = (uint8_t *)&q->frame; | |
721 | ||
722 | init_get_bits(&q->gb, buf, 8 * buf_size); | |
723 | ||
724 | memset(&q->frame, 0, sizeof(QCELPFrame)); | |
725 | ||
726 | for (; bitmaps < bitmaps_end; bitmaps++) | |
727 | unpacked_data[bitmaps->index] |= get_bits(&q->gb, bitmaps->bitlen) << bitmaps->bitpos; | |
728 | ||
729 | // Check for erasures/blanks on rates 1, 1/4 and 1/8. | |
730 | if (q->frame.reserved) { | |
731 | warn_insufficient_frame_quality(avctx, "Wrong data in reserved frame area."); | |
732 | goto erasure; | |
733 | } | |
734 | if (q->bitrate == RATE_QUARTER && | |
735 | codebook_sanity_check_for_rate_quarter(q->frame.cbgain)) { | |
736 | warn_insufficient_frame_quality(avctx, "Codebook gain sanity check failed."); | |
737 | goto erasure; | |
738 | } | |
739 | ||
740 | if (q->bitrate >= RATE_HALF) { | |
741 | for (i = 0; i < 4; i++) { | |
742 | if (q->frame.pfrac[i] && q->frame.plag[i] >= 124) { | |
743 | warn_insufficient_frame_quality(avctx, "Cannot initialize pitch filter."); | |
744 | goto erasure; | |
745 | } | |
746 | } | |
747 | } | |
748 | } | |
749 | ||
750 | decode_gain_and_index(q, gain); | |
751 | compute_svector(q, gain, outbuffer); | |
752 | ||
753 | if (decode_lspf(q, quantized_lspf) < 0) { | |
754 | warn_insufficient_frame_quality(avctx, "Badly received packets in frame."); | |
755 | goto erasure; | |
756 | } | |
757 | ||
758 | apply_pitch_filters(q, outbuffer); | |
759 | ||
760 | if (q->bitrate == I_F_Q) { | |
761 | erasure: | |
762 | q->bitrate = I_F_Q; | |
763 | q->erasure_count++; | |
764 | decode_gain_and_index(q, gain); | |
765 | compute_svector(q, gain, outbuffer); | |
766 | decode_lspf(q, quantized_lspf); | |
767 | apply_pitch_filters(q, outbuffer); | |
768 | } else | |
769 | q->erasure_count = 0; | |
770 | ||
771 | formant_mem = q->formant_mem + 10; | |
772 | for (i = 0; i < 4; i++) { | |
773 | interpolate_lpc(q, quantized_lspf, lpc, i); | |
774 | ff_celp_lp_synthesis_filterf(formant_mem, lpc, | |
775 | outbuffer + i * 40, 40, 10); | |
776 | formant_mem += 40; | |
777 | } | |
778 | ||
779 | // postfilter, as per TIA/EIA/IS-733 2.4.8.6 | |
780 | postfilter(q, outbuffer, lpc); | |
781 | ||
782 | memcpy(q->formant_mem, q->formant_mem + 160, 10 * sizeof(float)); | |
783 | ||
784 | memcpy(q->prev_lspf, quantized_lspf, sizeof(q->prev_lspf)); | |
785 | q->prev_bitrate = q->bitrate; | |
786 | ||
787 | *got_frame_ptr = 1; | |
788 | ||
789 | return buf_size; | |
790 | } | |
791 | ||
792 | AVCodec ff_qcelp_decoder = { | |
793 | .name = "qcelp", | |
794 | .long_name = NULL_IF_CONFIG_SMALL("QCELP / PureVoice"), | |
795 | .type = AVMEDIA_TYPE_AUDIO, | |
796 | .id = AV_CODEC_ID_QCELP, | |
797 | .init = qcelp_decode_init, | |
798 | .decode = qcelp_decode_frame, | |
799 | .capabilities = CODEC_CAP_DR1, | |
800 | .priv_data_size = sizeof(QCELPContext), | |
801 | }; |