Removes misleading const qualifier, gets rid of two compiler warnings
[ffmpeg.git] / libavcodec / qcelpdec.c
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 qcelpdec.c
24  * QCELP decoder
25  * @author Reynaldo H. Verdejo Pinochet
26  * @remark FFmpeg merging spearheaded by Kenan Gillet
27  */
28
29 #include <stddef.h>
30
31 #include "avcodec.h"
32 #include "bitstream.h"
33
34 #include "qcelpdata.h"
35
36 #include "celp_math.h"
37 #include "celp_filters.h"
38
39 #undef NDEBUG
40 #include <assert.h>
41
42 typedef enum
43 {
44     I_F_Q = -1,    /*!< insufficient frame quality */
45     SILENCE,
46     RATE_OCTAVE,
47     RATE_QUARTER,
48     RATE_HALF,
49     RATE_FULL
50 } qcelp_packet_rate;
51
52 typedef struct
53 {
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 } QCELPContext;
73
74 /**
75  * Reconstructs LPC coefficients from the line spectral pair frequencies.
76  *
77  * TIA/EIA/IS-733 2.4.3.3.5
78  */
79 void ff_qcelp_lspf2lpc(const float *lspf, float *lpc);
80
81 static void weighted_vector_sumf(float *out, const float *in_a,
82                                  const float *in_b, float weight_coeff_a,
83                                  float weight_coeff_b, int length)
84 {
85     int i;
86
87     for(i=0; i<length; i++)
88         out[i] = weight_coeff_a * in_a[i]
89                + weight_coeff_b * in_b[i];
90 }
91
92 /**
93  * Initialize the speech codec according to the specification.
94  *
95  * TIA/EIA/IS-733 2.4.9
96  */
97 static av_cold int qcelp_decode_init(AVCodecContext *avctx)
98 {
99     QCELPContext *q = avctx->priv_data;
100     int i;
101
102     avctx->sample_fmt = SAMPLE_FMT_FLT;
103
104     for(i=0; i<10; i++)
105         q->prev_lspf[i] = (i+1)/11.;
106
107     return 0;
108 }
109
110 /**
111  * Decodes the 10 quantized LSP frequencies from the LSPV/LSP
112  * transmission codes of any bitrate and checks for badly received packets.
113  *
114  * @param q the context
115  * @param lspf line spectral pair frequencies
116  *
117  * @return 0 on success, -1 if the packet is badly received
118  *
119  * TIA/EIA/IS-733 2.4.3.2.6.2-2, 2.4.8.7.3
120  */
121 static int decode_lspf(QCELPContext *q, float *lspf)
122 {
123     int i;
124     float tmp_lspf, smooth, erasure_coeff;
125     const float *predictors;
126
127     if(q->bitrate == RATE_OCTAVE || q->bitrate == I_F_Q)
128     {
129         predictors = (q->prev_bitrate != RATE_OCTAVE &&
130                        q->prev_bitrate != I_F_Q ?
131                        q->prev_lspf : q->predictor_lspf);
132
133         if(q->bitrate == RATE_OCTAVE)
134         {
135             q->octave_count++;
136
137             for(i=0; i<10; i++)
138             {
139                 q->predictor_lspf[i] =
140                              lspf[i] = (q->frame.lspv[i] ?  QCELP_LSP_SPREAD_FACTOR
141                                                          : -QCELP_LSP_SPREAD_FACTOR)
142                                      + predictors[i] * QCELP_LSP_OCTAVE_PREDICTOR
143                                      + (i + 1) * ((1 - QCELP_LSP_OCTAVE_PREDICTOR)/11);
144             }
145             smooth = (q->octave_count < 10 ? .875 : 0.1);
146         }else
147         {
148             erasure_coeff = QCELP_LSP_OCTAVE_PREDICTOR;
149
150             assert(q->bitrate == I_F_Q);
151
152             if(q->erasure_count > 1)
153                 erasure_coeff *= (q->erasure_count < 4 ? 0.9 : 0.7);
154
155             for(i=0; i<10; i++)
156             {
157                 q->predictor_lspf[i] =
158                              lspf[i] = (i + 1) * ( 1 - erasure_coeff)/11
159                                      + erasure_coeff * predictors[i];
160             }
161             smooth = 0.125;
162         }
163
164         // Check the stability of the LSP frequencies.
165         lspf[0] = FFMAX(lspf[0], QCELP_LSP_SPREAD_FACTOR);
166         for(i=1; i<10; i++)
167             lspf[i] = FFMAX(lspf[i], (lspf[i-1] + QCELP_LSP_SPREAD_FACTOR));
168
169         lspf[9] = FFMIN(lspf[9], (1.0 - QCELP_LSP_SPREAD_FACTOR));
170         for(i=9; i>0; i--)
171             lspf[i-1] = FFMIN(lspf[i-1], (lspf[i] - QCELP_LSP_SPREAD_FACTOR));
172
173         // Low-pass filter the LSP frequencies.
174         weighted_vector_sumf(lspf, lspf, q->prev_lspf, smooth, 1.0-smooth, 10);
175     }else
176     {
177         q->octave_count = 0;
178
179         tmp_lspf = 0.;
180         for(i=0; i<5 ; i++)
181         {
182             lspf[2*i+0] = tmp_lspf += qcelp_lspvq[i][q->frame.lspv[i]][0] * 0.0001;
183             lspf[2*i+1] = tmp_lspf += qcelp_lspvq[i][q->frame.lspv[i]][1] * 0.0001;
184         }
185
186         // Check for badly received packets.
187         if(q->bitrate == RATE_QUARTER)
188         {
189             if(lspf[9] <= .70 || lspf[9] >=  .97)
190                 return -1;
191             for(i=3; i<10; i++)
192                 if(fabs(lspf[i] - lspf[i-2]) < .08)
193                     return -1;
194         }else
195         {
196             if(lspf[9] <= .66 || lspf[9] >= .985)
197                 return -1;
198             for(i=4; i<10; i++)
199                 if (fabs(lspf[i] - lspf[i-4]) < .0931)
200                     return -1;
201         }
202     }
203     return 0;
204 }
205
206 /**
207  * Converts codebook transmission codes to GAIN and INDEX.
208  *
209  * @param q the context
210  * @param gain array holding the decoded gain
211  *
212  * TIA/EIA/IS-733 2.4.6.2
213  */
214 static void decode_gain_and_index(QCELPContext  *q,
215                                   float *gain) {
216     int   i, subframes_count, g1[16];
217     float slope;
218
219     if(q->bitrate >= RATE_QUARTER)
220     {
221         switch(q->bitrate)
222         {
223             case RATE_FULL: subframes_count = 16; break;
224             case RATE_HALF: subframes_count = 4;  break;
225             default:        subframes_count = 5;
226         }
227         for(i=0; i<subframes_count; i++)
228         {
229             g1[i] = 4 * q->frame.cbgain[i];
230             if(q->bitrate == RATE_FULL && !((i+1) & 3))
231             {
232                 g1[i] += av_clip((g1[i-1] + g1[i-2] + g1[i-3]) / 3 - 6, 0, 32);
233             }
234
235             gain[i] = qcelp_g12ga[g1[i]];
236
237             if(q->frame.cbsign[i])
238             {
239                 gain[i] = -gain[i];
240                 q->frame.cindex[i] = (q->frame.cindex[i]-89) & 127;
241             }
242         }
243
244         q->prev_g1[0] = g1[i-2];
245         q->prev_g1[1] = g1[i-1];
246         q->last_codebook_gain = qcelp_g12ga[g1[i-1]];
247
248         if(q->bitrate == RATE_QUARTER)
249         {
250             // Provide smoothing of the unvoiced excitation energy.
251             gain[7] =     gain[4];
252             gain[6] = 0.4*gain[3] + 0.6*gain[4];
253             gain[5] =     gain[3];
254             gain[4] = 0.8*gain[2] + 0.2*gain[3];
255             gain[3] = 0.2*gain[1] + 0.8*gain[2];
256             gain[2] =     gain[1];
257             gain[1] = 0.6*gain[0] + 0.4*gain[1];
258         }
259     }else
260     {
261         if(q->bitrate == RATE_OCTAVE)
262         {
263             g1[0] = 2 * q->frame.cbgain[0]
264                   + av_clip((q->prev_g1[0] + q->prev_g1[1]) / 2 - 5, 0, 54);
265             subframes_count = 8;
266         }else
267         {
268             assert(q->bitrate == I_F_Q);
269
270             g1[0] = q->prev_g1[1];
271             switch(q->erasure_count)
272             {
273                 case 1 : break;
274                 case 2 : g1[0] -= 1; break;
275                 case 3 : g1[0] -= 2; break;
276                 default: g1[0] -= 6;
277             }
278             if(g1[0] < 0)
279                 g1[0] = 0;
280             subframes_count = 4;
281         }
282         // This interpolation is done to produce smoother background noise.
283         slope = 0.5*(qcelp_g12ga[g1[0]] - q->last_codebook_gain) / subframes_count;
284         for(i=1; i<=subframes_count; i++)
285             gain[i-1] = q->last_codebook_gain + slope * i;
286
287         q->last_codebook_gain = gain[i-2];
288         q->prev_g1[0] = q->prev_g1[1];
289         q->prev_g1[1] = g1[0];
290     }
291 }
292
293 /**
294  * If the received packet is Rate 1/4 a further sanity check is made of the
295  * codebook gain.
296  *
297  * @param cbgain the unpacked cbgain array
298  * @return -1 if the sanity check fails, 0 otherwise
299  *
300  * TIA/EIA/IS-733 2.4.8.7.3
301  */
302 static int codebook_sanity_check_for_rate_quarter(const uint8_t *cbgain)
303 {
304     int i, diff, prev_diff=0;
305
306     for(i=1; i<5; i++)
307     {
308         diff = cbgain[i] - cbgain[i-1];
309         if(FFABS(diff) > 10)
310             return -1;
311         else if(FFABS(diff - prev_diff) > 12)
312             return -1;
313         prev_diff = diff;
314     }
315     return 0;
316 }
317
318 /**
319  * Computes the scaled codebook vector Cdn From INDEX and GAIN
320  * for all rates.
321  *
322  * The specification lacks some information here.
323  *
324  * TIA/EIA/IS-733 has an omission on the codebook index determination
325  * formula for RATE_FULL and RATE_HALF frames at section 2.4.8.1.1. It says
326  * you have to subtract the decoded index parameter from the given scaled
327  * codebook vector index 'n' to get the desired circular codebook index, but
328  * it does not mention that you have to clamp 'n' to [0-9] in order to get
329  * RI-compliant results.
330  *
331  * The reason for this mistake seems to be the fact they forgot to mention you
332  * have to do these calculations per codebook subframe and adjust given
333  * equation values accordingly.
334  *
335  * @param q the context
336  * @param gain array holding the 4 pitch subframe gain values
337  * @param cdn_vector array for the generated scaled codebook vector
338  */
339 static void compute_svector(QCELPContext *q, const float *gain,
340                             float *cdn_vector)
341 {
342     int      i, j, k;
343     uint16_t cbseed, cindex;
344     float    *rnd, tmp_gain, fir_filter_value;
345
346     switch(q->bitrate)
347     {
348         case RATE_FULL:
349             for(i=0; i<16; i++)
350             {
351                 tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO;
352                 cindex = -q->frame.cindex[i];
353                 for(j=0; j<10; j++)
354                     *cdn_vector++ = tmp_gain * qcelp_rate_full_codebook[cindex++ & 127];
355             }
356         break;
357         case RATE_HALF:
358             for(i=0; i<4; i++)
359             {
360                 tmp_gain = gain[i] * QCELP_RATE_HALF_CODEBOOK_RATIO;
361                 cindex = -q->frame.cindex[i];
362                 for (j = 0; j < 40; j++)
363                 *cdn_vector++ = tmp_gain * qcelp_rate_half_codebook[cindex++ & 127];
364             }
365         break;
366         case RATE_QUARTER:
367             cbseed = (0x0003 & q->frame.lspv[4])<<14 |
368                      (0x003F & q->frame.lspv[3])<< 8 |
369                      (0x0060 & q->frame.lspv[2])<< 1 |
370                      (0x0007 & q->frame.lspv[1])<< 3 |
371                      (0x0038 & q->frame.lspv[0])>> 3 ;
372             rnd = q->rnd_fir_filter_mem + 20;
373             for(i=0; i<8; i++)
374             {
375                 tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0);
376                 for(k=0; k<20; k++)
377                 {
378                     cbseed = 521 * cbseed + 259;
379                     *rnd = (int16_t)cbseed;
380
381                     // FIR filter
382                     fir_filter_value = 0.0;
383                     for(j=0; j<10; j++)
384                         fir_filter_value += qcelp_rnd_fir_coefs[j ]
385                                           * (rnd[-j ] + rnd[-20+j]);
386
387                     fir_filter_value += qcelp_rnd_fir_coefs[10] * rnd[-10];
388                     *cdn_vector++ = tmp_gain * fir_filter_value;
389                     rnd++;
390                 }
391             }
392             memcpy(q->rnd_fir_filter_mem, q->rnd_fir_filter_mem + 160, 20 * sizeof(float));
393         break;
394         case RATE_OCTAVE:
395             cbseed = q->first16bits;
396             for(i=0; i<8; i++)
397             {
398                 tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0);
399                 for(j=0; j<20; j++)
400                 {
401                     cbseed = 521 * cbseed + 259;
402                     *cdn_vector++ = tmp_gain * (int16_t)cbseed;
403                 }
404             }
405         break;
406         case I_F_Q:
407             cbseed = -44; // random codebook index
408             for(i=0; i<4; i++)
409             {
410                 tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO;
411                 for(j=0; j<40; j++)
412                     *cdn_vector++ = tmp_gain * qcelp_rate_full_codebook[cbseed++ & 127];
413             }
414         break;
415     }
416 }
417
418 /**
419  * Apply generic gain control.
420  *
421  * @param v_out output vector
422  * @param v_in gain-controlled vector
423  * @param v_ref vector to control gain of
424  *
425  * FIXME: If v_ref is a zero vector, it energy is zero
426  *        and the behavior of the gain control is
427  *        undefined in the specs.
428  *
429  * TIA/EIA/IS-733 2.4.8.3-2/3/4/5, 2.4.8.6
430  */
431 static void apply_gain_ctrl(float *v_out, const float *v_ref,
432                             const float *v_in)
433 {
434     int   i, j, len;
435     float scalefactor;
436
437     for(i=0, j=0; i<4; i++)
438     {
439         scalefactor = ff_dot_productf(v_in + j, v_in + j, 40);
440         if(scalefactor)
441             scalefactor = sqrt(ff_dot_productf(v_ref + j, v_ref + j, 40)
442                         / scalefactor);
443         else
444             av_log_missing_feature(NULL, "Zero energy for gain control", 1);
445         for(len=j+40; j<len; j++)
446             v_out[j] = scalefactor * v_in[j];
447     }
448 }
449
450 /**
451  * Apply filter in pitch-subframe steps.
452  *
453  * @param memory buffer for the previous state of the filter
454  *        - must be able to contain 303 elements
455  *        - the 143 first elements are from the previous state
456  *        - the next 160 are for output
457  * @param v_in input filter vector
458  * @param gain per-subframe gain array, each element is between 0.0 and 2.0
459  * @param lag per-subframe lag array, each element is
460  *        - between 16 and 143 if its corresponding pfrac is 0,
461  *        - between 16 and 139 otherwise
462  * @param pfrac per-subframe boolean array, 1 if the lag is fractional, 0
463  *        otherwise
464  *
465  * @return filter output vector
466  */
467 static const float *do_pitchfilter(float memory[303], const float v_in[160],
468                                    const float gain[4], const uint8_t *lag,
469                                    const uint8_t pfrac[4])
470 {
471     int         i, j;
472     float       *v_lag, *v_out;
473     const float *v_len;
474
475     v_out = memory + 143; // Output vector starts at memory[143].
476
477     for(i=0; i<4; i++)
478     {
479         if(gain[i])
480         {
481             v_lag = memory + 143 + 40 * i - lag[i];
482             for(v_len=v_in+40; v_in<v_len; v_in++)
483             {
484                 if(pfrac[i]) // If it is a fractional lag...
485                 {
486                     for(j=0, *v_out=0.; j<4; j++)
487                         *v_out += qcelp_hammsinc_table[j] * (v_lag[j-4] + v_lag[3-j]);
488                 }else
489                     *v_out = *v_lag;
490
491                 *v_out = *v_in + gain[i] * *v_out;
492
493                 v_lag++;
494                 v_out++;
495             }
496         }else
497         {
498             memcpy(v_out, v_in, 40 * sizeof(float));
499             v_in  += 40;
500             v_out += 40;
501         }
502     }
503
504     memmove(memory, memory + 160, 143 * sizeof(float));
505     return memory + 143;
506 }
507
508 /**
509  * Apply pitch synthesis filter and pitch prefilter to the scaled codebook vector.
510  * TIA/EIA/IS-733 2.4.5.2
511  *
512  * @param q the context
513  * @param cdn_vector the scaled codebook vector
514  */
515 static void apply_pitch_filters(QCELPContext *q, float *cdn_vector)
516 {
517     int         i;
518     const float *v_synthesis_filtered, *v_pre_filtered;
519
520     if(q->bitrate >= RATE_HALF ||
521        (q->bitrate == I_F_Q && (q->prev_bitrate >= RATE_HALF)))
522     {
523
524         if(q->bitrate >= RATE_HALF)
525         {
526
527             // Compute gain & lag for the whole frame.
528             for(i=0; i<4; i++)
529             {
530                 q->pitch_gain[i] = q->frame.plag[i] ? (q->frame.pgain[i] + 1) * 0.25 : 0.0;
531
532                 q->pitch_lag[i] = q->frame.plag[i] + 16;
533             }
534         }else
535         {
536             float max_pitch_gain = q->erasure_count < 3 ? 0.9 - 0.3 * (q->erasure_count - 1) : 0.0;
537             for(i=0; i<4; i++)
538                 q->pitch_gain[i] = FFMIN(q->pitch_gain[i], max_pitch_gain);
539
540             memset(q->frame.pfrac, 0, sizeof(q->frame.pfrac));
541         }
542
543         // pitch synthesis filter
544         v_synthesis_filtered = do_pitchfilter(q->pitch_synthesis_filter_mem,
545                                               cdn_vector, q->pitch_gain,
546                                               q->pitch_lag, q->frame.pfrac);
547
548         // pitch prefilter update
549         for(i=0; i<4; i++)
550             q->pitch_gain[i] = 0.5 * FFMIN(q->pitch_gain[i], 1.0);
551
552         v_pre_filtered = do_pitchfilter(q->pitch_pre_filter_mem,
553                                         v_synthesis_filtered,
554                                         q->pitch_gain, q->pitch_lag,
555                                         q->frame.pfrac);
556
557         apply_gain_ctrl(cdn_vector, v_synthesis_filtered, v_pre_filtered);
558     }else
559     {
560         memcpy(q->pitch_synthesis_filter_mem, cdn_vector + 17,
561                143 * sizeof(float));
562         memcpy(q->pitch_pre_filter_mem, cdn_vector + 17, 143 * sizeof(float));
563         memset(q->pitch_gain, 0, sizeof(q->pitch_gain));
564         memset(q->pitch_lag,  0, sizeof(q->pitch_lag));
565     }
566 }
567
568 /**
569  * Interpolates LSP frequencies and computes LPC coefficients
570  * for a given bitrate & pitch subframe.
571  *
572  * TIA/EIA/IS-733 2.4.3.3.4
573  *
574  * @param q the context
575  * @param curr_lspf LSP frequencies vector of the current frame
576  * @param lpc float vector for the resulting LPC
577  * @param subframe_num frame number in decoded stream
578  */
579 void interpolate_lpc(QCELPContext *q, const float *curr_lspf, float *lpc,
580                      const int subframe_num)
581 {
582     float interpolated_lspf[10];
583     float weight;
584
585     if(q->bitrate >= RATE_QUARTER)
586         weight = 0.25 * (subframe_num + 1);
587     else if(q->bitrate == RATE_OCTAVE && !subframe_num)
588         weight = 0.625;
589     else
590         weight = 1.0;
591
592     if(weight != 1.0)
593     {
594         weighted_vector_sumf(interpolated_lspf, curr_lspf, q->prev_lspf,
595                              weight, 1.0 - weight, 10);
596         ff_qcelp_lspf2lpc(interpolated_lspf, lpc);
597     }else if(q->bitrate >= RATE_QUARTER ||
598              (q->bitrate == I_F_Q && !subframe_num))
599         ff_qcelp_lspf2lpc(curr_lspf, lpc);
600 }
601
602 static int buf_size2bitrate(const int buf_size)
603 {
604     switch(buf_size)
605     {
606         case 35: return RATE_FULL;
607         case 17: return RATE_HALF;
608         case  8: return RATE_QUARTER;
609         case  4: return RATE_OCTAVE;
610         case  1: return SILENCE;
611     }
612
613     return -1;
614 }
615
616 /**
617  * Determine the bitrate from the frame size and/or the first byte of the frame.
618  *
619  * @param avctx the AV codec context
620  * @param buf_size length of the buffer
621  * @param buf the bufffer
622  *
623  * @return the bitrate on success,
624  *         I_F_Q  if the bitrate cannot be satisfactorily determined
625  *
626  * TIA/EIA/IS-733 2.4.8.7.1
627  */
628 static int determine_bitrate(AVCodecContext *avctx, const int buf_size,
629                              uint8_t **buf)
630 {
631     qcelp_packet_rate bitrate;
632
633     if((bitrate = buf_size2bitrate(buf_size)) >= 0)
634     {
635         if(bitrate > **buf)
636         {
637             av_log(avctx, AV_LOG_WARNING,
638                    "Claimed bitrate and buffer size mismatch.\n");
639             bitrate = **buf;
640         }else if(bitrate < **buf)
641         {
642             av_log(avctx, AV_LOG_ERROR,
643                    "Buffer is too small for the claimed bitrate.\n");
644             return I_F_Q;
645         }
646         (*buf)++;
647     }else if((bitrate = buf_size2bitrate(buf_size + 1)) >= 0)
648     {
649         av_log(avctx, AV_LOG_WARNING,
650                "Bitrate byte is missing, guessing the bitrate from packet size.\n");
651     }else
652         return I_F_Q;
653
654     if(bitrate == SILENCE)
655     {
656         // FIXME: the decoder should not handle SILENCE frames as I_F_Q frames
657         av_log_missing_feature(avctx, "Blank frame", 1);
658         bitrate = I_F_Q;
659     }
660     return bitrate;
661 }
662
663 static void warn_insufficient_frame_quality(AVCodecContext *avctx,
664                                             const char *message)
665 {
666     av_log(avctx, AV_LOG_WARNING, "Frame #%d, IFQ: %s\n", avctx->frame_number,
667            message);
668 }
669
670 static int qcelp_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
671                               uint8_t *buf, const int buf_size)
672 {
673     QCELPContext *q = avctx->priv_data;
674     float *outbuffer = data;
675     int   i;
676     float quantized_lspf[10], lpc[10];
677     float gain[16];
678     float *formant_mem;
679
680     if((q->bitrate = determine_bitrate(avctx, buf_size, &buf)) == I_F_Q)
681     {
682         warn_insufficient_frame_quality(avctx, "bitrate cannot be determined.");
683         goto erasure;
684     }
685
686     if(q->bitrate == RATE_OCTAVE &&
687        (q->first16bits = AV_RB16(buf)) == 0xFFFF)
688     {
689         warn_insufficient_frame_quality(avctx, "Bitrate is 1/8 and first 16 bits are on.");
690         goto erasure;
691     }
692
693     if(q->bitrate > SILENCE)
694     {
695         const QCELPBitmap *bitmaps     = qcelp_unpacking_bitmaps_per_rate[q->bitrate];
696         const QCELPBitmap *bitmaps_end = qcelp_unpacking_bitmaps_per_rate[q->bitrate]
697                                        + qcelp_unpacking_bitmaps_lengths[q->bitrate];
698         uint8_t           *unpacked_data = (uint8_t *)&q->frame;
699
700         init_get_bits(&q->gb, buf, 8*buf_size);
701
702         memset(&q->frame, 0, sizeof(QCELPFrame));
703
704         for(; bitmaps < bitmaps_end; bitmaps++)
705             unpacked_data[bitmaps->index] |= get_bits(&q->gb, bitmaps->bitlen) << bitmaps->bitpos;
706
707         // Check for erasures/blanks on rates 1, 1/4 and 1/8.
708         if(q->frame.reserved)
709         {
710             warn_insufficient_frame_quality(avctx, "Wrong data in reserved frame area.");
711             goto erasure;
712         }
713         if(q->bitrate == RATE_QUARTER &&
714            codebook_sanity_check_for_rate_quarter(q->frame.cbgain))
715         {
716             warn_insufficient_frame_quality(avctx, "Codebook gain sanity check failed.");
717             goto erasure;
718         }
719
720         if(q->bitrate >= RATE_HALF)
721         {
722             for(i=0; i<4; i++)
723             {
724                 if(q->frame.pfrac[i] && q->frame.plag[i] >= 124)
725                 {
726                     warn_insufficient_frame_quality(avctx, "Cannot initialize pitch filter.");
727                     goto erasure;
728                 }
729             }
730         }
731     }
732
733     decode_gain_and_index(q, gain);
734     compute_svector(q, gain, outbuffer);
735
736     if(decode_lspf(q, quantized_lspf) < 0)
737     {
738         warn_insufficient_frame_quality(avctx, "Badly received packets in frame.");
739         goto erasure;
740     }
741
742
743     apply_pitch_filters(q, outbuffer);
744
745     if(q->bitrate == I_F_Q)
746     {
747 erasure:
748         q->bitrate = I_F_Q;
749         q->erasure_count++;
750         decode_gain_and_index(q, gain);
751         compute_svector(q, gain, outbuffer);
752         decode_lspf(q, quantized_lspf);
753         apply_pitch_filters(q, outbuffer);
754     }else
755         q->erasure_count = 0;
756
757     formant_mem = q->formant_mem + 10;
758     for(i=0; i<4; i++)
759     {
760         interpolate_lpc(q, quantized_lspf, lpc, i);
761         ff_celp_lp_synthesis_filterf(formant_mem, lpc, outbuffer + i * 40, 40,
762                                      10);
763         formant_mem += 40;
764     }
765     memcpy(q->formant_mem, q->formant_mem + 160, 10 * sizeof(float));
766
767     // FIXME: postfilter and final gain control should be here.
768     // TIA/EIA/IS-733 2.4.8.6
769
770     formant_mem = q->formant_mem + 10;
771     for(i=0; i<160; i++)
772         *outbuffer++ = av_clipf(*formant_mem++, QCELP_CLIP_LOWER_BOUND,
773                                 QCELP_CLIP_UPPER_BOUND);
774
775     memcpy(q->prev_lspf, quantized_lspf, sizeof(q->prev_lspf));
776     q->prev_bitrate = q->bitrate;
777
778     *data_size = 160 * sizeof(*outbuffer);
779
780     return *data_size;
781 }
782
783 AVCodec qcelp_decoder =
784 {
785     .name   = "qcelp",
786     .type   = CODEC_TYPE_AUDIO,
787     .id     = CODEC_ID_QCELP,
788     .init   = qcelp_decode_init,
789     .decode = qcelp_decode_frame,
790     .priv_data_size = sizeof(QCELPContext),
791     .long_name = NULL_IF_CONFIG_SMALL("QCELP / PureVoice"),
792 };