Initial import of MPlayer SVN rev 28382 and FFmpeg SVN rev 16846.
[vaapi:athaifas-mplayer.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  * @remark Development mentored by Benjamin Larson
28  */
29
30 #include <stddef.h>
31
32 #include "avcodec.h"
33 #include "internal.h"
34 #include "bitstream.h"
35
36 #include "qcelpdata.h"
37
38 #include "celp_math.h"
39 #include "celp_filters.h"
40
41 #undef NDEBUG
42 #include <assert.h>
43
44 typedef enum
45 {
46     I_F_Q = -1,    /*!< insufficient frame quality */
47     SILENCE,
48     RATE_OCTAVE,
49     RATE_QUARTER,
50     RATE_HALF,
51     RATE_FULL
52 } qcelp_packet_rate;
53
54 typedef struct
55 {
56     GetBitContext     gb;
57     qcelp_packet_rate bitrate;
58     QCELPFrame        frame;    /*!< unpacked data frame */
59
60     uint8_t  erasure_count;
61     uint8_t  octave_count;      /*!< count the consecutive RATE_OCTAVE frames */
62     float    prev_lspf[10];
63     float    predictor_lspf[10];/*!< LSP predictor for RATE_OCTAVE and I_F_Q */
64     float    pitch_synthesis_filter_mem[303];
65     float    pitch_pre_filter_mem[303];
66     float    rnd_fir_filter_mem[180];
67     float    formant_mem[170];
68     float    last_codebook_gain;
69     int      prev_g1[2];
70     int      prev_bitrate;
71     float    pitch_gain[4];
72     uint8_t  pitch_lag[4];
73     uint16_t first16bits;
74     uint8_t  warned_buf_mismatch_bitrate;
75 } QCELPContext;
76
77 /**
78  * Reconstructs LPC coefficients from the line spectral pair frequencies.
79  *
80  * TIA/EIA/IS-733 2.4.3.3.5
81  */
82 void ff_qcelp_lspf2lpc(const float *lspf, float *lpc);
83
84 static void weighted_vector_sumf(float *out, const float *in_a,
85                                  const float *in_b, float weight_coeff_a,
86                                  float weight_coeff_b, int length)
87 {
88     int i;
89
90     for(i=0; i<length; i++)
91         out[i] = weight_coeff_a * in_a[i]
92                + weight_coeff_b * in_b[i];
93 }
94
95 /**
96  * Initialize the speech codec according to the specification.
97  *
98  * TIA/EIA/IS-733 2.4.9
99  */
100 static av_cold int qcelp_decode_init(AVCodecContext *avctx)
101 {
102     QCELPContext *q = avctx->priv_data;
103     int i;
104
105     avctx->sample_fmt = SAMPLE_FMT_FLT;
106
107     for(i=0; i<10; i++)
108         q->prev_lspf[i] = (i+1)/11.;
109
110     return 0;
111 }
112
113 /**
114  * Decodes the 10 quantized LSP frequencies from the LSPV/LSP
115  * transmission codes of any bitrate and checks for badly received packets.
116  *
117  * @param q the context
118  * @param lspf line spectral pair frequencies
119  *
120  * @return 0 on success, -1 if the packet is badly received
121  *
122  * TIA/EIA/IS-733 2.4.3.2.6.2-2, 2.4.8.7.3
123  */
124 static int decode_lspf(QCELPContext *q, float *lspf)
125 {
126     int i;
127     float tmp_lspf, smooth, erasure_coeff;
128     const float *predictors;
129
130     if(q->bitrate == RATE_OCTAVE || q->bitrate == I_F_Q)
131     {
132         predictors = (q->prev_bitrate != RATE_OCTAVE &&
133                        q->prev_bitrate != I_F_Q ?
134                        q->prev_lspf : q->predictor_lspf);
135
136         if(q->bitrate == RATE_OCTAVE)
137         {
138             q->octave_count++;
139
140             for(i=0; i<10; i++)
141             {
142                 q->predictor_lspf[i] =
143                              lspf[i] = (q->frame.lspv[i] ?  QCELP_LSP_SPREAD_FACTOR
144                                                          : -QCELP_LSP_SPREAD_FACTOR)
145                                      + predictors[i] * QCELP_LSP_OCTAVE_PREDICTOR
146                                      + (i + 1) * ((1 - QCELP_LSP_OCTAVE_PREDICTOR)/11);
147             }
148             smooth = (q->octave_count < 10 ? .875 : 0.1);
149         }else
150         {
151             erasure_coeff = QCELP_LSP_OCTAVE_PREDICTOR;
152
153             assert(q->bitrate == I_F_Q);
154
155             if(q->erasure_count > 1)
156                 erasure_coeff *= (q->erasure_count < 4 ? 0.9 : 0.7);
157
158             for(i=0; i<10; i++)
159             {
160                 q->predictor_lspf[i] =
161                              lspf[i] = (i + 1) * ( 1 - erasure_coeff)/11
162                                      + erasure_coeff * predictors[i];
163             }
164             smooth = 0.125;
165         }
166
167         // Check the stability of the LSP frequencies.
168         lspf[0] = FFMAX(lspf[0], QCELP_LSP_SPREAD_FACTOR);
169         for(i=1; i<10; i++)
170             lspf[i] = FFMAX(lspf[i], (lspf[i-1] + QCELP_LSP_SPREAD_FACTOR));
171
172         lspf[9] = FFMIN(lspf[9], (1.0 - QCELP_LSP_SPREAD_FACTOR));
173         for(i=9; i>0; i--)
174             lspf[i-1] = FFMIN(lspf[i-1], (lspf[i] - QCELP_LSP_SPREAD_FACTOR));
175
176         // Low-pass filter the LSP frequencies.
177         weighted_vector_sumf(lspf, lspf, q->prev_lspf, smooth, 1.0-smooth, 10);
178     }else
179     {
180         q->octave_count = 0;
181
182         tmp_lspf = 0.;
183         for(i=0; i<5 ; i++)
184         {
185             lspf[2*i+0] = tmp_lspf += qcelp_lspvq[i][q->frame.lspv[i]][0] * 0.0001;
186             lspf[2*i+1] = tmp_lspf += qcelp_lspvq[i][q->frame.lspv[i]][1] * 0.0001;
187         }
188
189         // Check for badly received packets.
190         if(q->bitrate == RATE_QUARTER)
191         {
192             if(lspf[9] <= .70 || lspf[9] >=  .97)
193                 return -1;
194             for(i=3; i<10; i++)
195                 if(fabs(lspf[i] - lspf[i-2]) < .08)
196                     return -1;
197         }else
198         {
199             if(lspf[9] <= .66 || lspf[9] >= .985)
200                 return -1;
201             for(i=4; i<10; i++)
202                 if (fabs(lspf[i] - lspf[i-4]) < .0931)
203                     return -1;
204         }
205     }
206     return 0;
207 }
208
209 /**
210  * Converts codebook transmission codes to GAIN and INDEX.
211  *
212  * @param q the context
213  * @param gain array holding the decoded gain
214  *
215  * TIA/EIA/IS-733 2.4.6.2
216  */
217 static void decode_gain_and_index(QCELPContext  *q,
218                                   float *gain) {
219     int   i, subframes_count, g1[16];
220     float slope;
221
222     if(q->bitrate >= RATE_QUARTER)
223     {
224         switch(q->bitrate)
225         {
226             case RATE_FULL: subframes_count = 16; break;
227             case RATE_HALF: subframes_count = 4;  break;
228             default:        subframes_count = 5;
229         }
230         for(i=0; i<subframes_count; i++)
231         {
232             g1[i] = 4 * q->frame.cbgain[i];
233             if(q->bitrate == RATE_FULL && !((i+1) & 3))
234             {
235                 g1[i] += av_clip((g1[i-1] + g1[i-2] + g1[i-3]) / 3 - 6, 0, 32);
236             }
237
238             gain[i] = qcelp_g12ga[g1[i]];
239
240             if(q->frame.cbsign[i])
241             {
242                 gain[i] = -gain[i];
243                 q->frame.cindex[i] = (q->frame.cindex[i]-89) & 127;
244             }
245         }
246
247         q->prev_g1[0] = g1[i-2];
248         q->prev_g1[1] = g1[i-1];
249         q->last_codebook_gain = qcelp_g12ga[g1[i-1]];
250
251         if(q->bitrate == RATE_QUARTER)
252         {
253             // Provide smoothing of the unvoiced excitation energy.
254             gain[7] =     gain[4];
255             gain[6] = 0.4*gain[3] + 0.6*gain[4];
256             gain[5] =     gain[3];
257             gain[4] = 0.8*gain[2] + 0.2*gain[3];
258             gain[3] = 0.2*gain[1] + 0.8*gain[2];
259             gain[2] =     gain[1];
260             gain[1] = 0.6*gain[0] + 0.4*gain[1];
261         }
262     }else
263     {
264         if(q->bitrate == RATE_OCTAVE)
265         {
266             g1[0] = 2 * q->frame.cbgain[0]
267                   + av_clip((q->prev_g1[0] + q->prev_g1[1]) / 2 - 5, 0, 54);
268             subframes_count = 8;
269         }else
270         {
271             assert(q->bitrate == I_F_Q);
272
273             g1[0] = q->prev_g1[1];
274             switch(q->erasure_count)
275             {
276                 case 1 : break;
277                 case 2 : g1[0] -= 1; break;
278                 case 3 : g1[0] -= 2; break;
279                 default: g1[0] -= 6;
280             }
281             if(g1[0] < 0)
282                 g1[0] = 0;
283             subframes_count = 4;
284         }
285         // This interpolation is done to produce smoother background noise.
286         slope = 0.5*(qcelp_g12ga[g1[0]] - q->last_codebook_gain) / subframes_count;
287         for(i=1; i<=subframes_count; i++)
288             gain[i-1] = q->last_codebook_gain + slope * i;
289
290         q->last_codebook_gain = gain[i-2];
291         q->prev_g1[0] = q->prev_g1[1];
292         q->prev_g1[1] = g1[0];
293     }
294 }
295
296 /**
297  * If the received packet is Rate 1/4 a further sanity check is made of the
298  * codebook gain.
299  *
300  * @param cbgain the unpacked cbgain array
301  * @return -1 if the sanity check fails, 0 otherwise
302  *
303  * TIA/EIA/IS-733 2.4.8.7.3
304  */
305 static int codebook_sanity_check_for_rate_quarter(const uint8_t *cbgain)
306 {
307     int i, diff, prev_diff=0;
308
309     for(i=1; i<5; i++)
310     {
311         diff = cbgain[i] - cbgain[i-1];
312         if(FFABS(diff) > 10)
313             return -1;
314         else if(FFABS(diff - prev_diff) > 12)
315             return -1;
316         prev_diff = diff;
317     }
318     return 0;
319 }
320
321 /**
322  * Computes the scaled codebook vector Cdn From INDEX and GAIN
323  * for all rates.
324  *
325  * The specification lacks some information here.
326  *
327  * TIA/EIA/IS-733 has an omission on the codebook index determination
328  * formula for RATE_FULL and RATE_HALF frames at section 2.4.8.1.1. It says
329  * you have to subtract the decoded index parameter from the given scaled
330  * codebook vector index 'n' to get the desired circular codebook index, but
331  * it does not mention that you have to clamp 'n' to [0-9] in order to get
332  * RI-compliant results.
333  *
334  * The reason for this mistake seems to be the fact they forgot to mention you
335  * have to do these calculations per codebook subframe and adjust given
336  * equation values accordingly.
337  *
338  * @param q the context
339  * @param gain array holding the 4 pitch subframe gain values
340  * @param cdn_vector array for the generated scaled codebook vector
341  */
342 static void compute_svector(QCELPContext *q, const float *gain,
343                             float *cdn_vector)
344 {
345     int      i, j, k;
346     uint16_t cbseed, cindex;
347     float    *rnd, tmp_gain, fir_filter_value;
348
349     switch(q->bitrate)
350     {
351         case RATE_FULL:
352             for(i=0; i<16; i++)
353             {
354                 tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO;
355                 cindex = -q->frame.cindex[i];
356                 for(j=0; j<10; j++)
357                     *cdn_vector++ = tmp_gain * qcelp_rate_full_codebook[cindex++ & 127];
358             }
359         break;
360         case RATE_HALF:
361             for(i=0; i<4; i++)
362             {
363                 tmp_gain = gain[i] * QCELP_RATE_HALF_CODEBOOK_RATIO;
364                 cindex = -q->frame.cindex[i];
365                 for (j = 0; j < 40; j++)
366                 *cdn_vector++ = tmp_gain * qcelp_rate_half_codebook[cindex++ & 127];
367             }
368         break;
369         case RATE_QUARTER:
370             cbseed = (0x0003 & q->frame.lspv[4])<<14 |
371                      (0x003F & q->frame.lspv[3])<< 8 |
372                      (0x0060 & q->frame.lspv[2])<< 1 |
373                      (0x0007 & q->frame.lspv[1])<< 3 |
374                      (0x0038 & q->frame.lspv[0])>> 3 ;
375             rnd = q->rnd_fir_filter_mem + 20;
376             for(i=0; i<8; i++)
377             {
378                 tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0);
379                 for(k=0; k<20; k++)
380                 {
381                     cbseed = 521 * cbseed + 259;
382                     *rnd = (int16_t)cbseed;
383
384                     // FIR filter
385                     fir_filter_value = 0.0;
386                     for(j=0; j<10; j++)
387                         fir_filter_value += qcelp_rnd_fir_coefs[j ]
388                                           * (rnd[-j ] + rnd[-20+j]);
389
390                     fir_filter_value += qcelp_rnd_fir_coefs[10] * rnd[-10];
391                     *cdn_vector++ = tmp_gain * fir_filter_value;
392                     rnd++;
393                 }
394             }
395             memcpy(q->rnd_fir_filter_mem, q->rnd_fir_filter_mem + 160, 20 * sizeof(float));
396         break;
397         case RATE_OCTAVE:
398             cbseed = q->first16bits;
399             for(i=0; i<8; i++)
400             {
401                 tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0);
402                 for(j=0; j<20; j++)
403                 {
404                     cbseed = 521 * cbseed + 259;
405                     *cdn_vector++ = tmp_gain * (int16_t)cbseed;
406                 }
407             }
408         break;
409         case I_F_Q:
410             cbseed = -44; // random codebook index
411             for(i=0; i<4; i++)
412             {
413                 tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO;
414                 for(j=0; j<40; j++)
415                     *cdn_vector++ = tmp_gain * qcelp_rate_full_codebook[cbseed++ & 127];
416             }
417         break;
418         case SILENCE:
419             memset(cdn_vector, 0, 160 * sizeof(float));
420         break;
421     }
422 }
423
424 /**
425  * Apply generic gain control.
426  *
427  * @param v_out output vector
428  * @param v_in gain-controlled vector
429  * @param v_ref vector to control gain of
430  *
431  * FIXME: If v_ref is a zero vector, it energy is zero
432  *        and the behavior of the gain control is
433  *        undefined in the specs.
434  *
435  * TIA/EIA/IS-733 2.4.8.3-2/3/4/5, 2.4.8.6
436  */
437 static void apply_gain_ctrl(float *v_out, const float *v_ref,
438                             const float *v_in)
439 {
440     int   i, j, len;
441     float scalefactor;
442
443     for(i=0, j=0; i<4; i++)
444     {
445         scalefactor = ff_dot_productf(v_in + j, v_in + j, 40);
446         if(scalefactor)
447             scalefactor = sqrt(ff_dot_productf(v_ref + j, v_ref + j, 40)
448                         / scalefactor);
449         else
450             ff_log_missing_feature(NULL, "Zero energy for gain control", 1);
451         for(len=j+40; j<len; j++)
452             v_out[j] = scalefactor * v_in[j];
453     }
454 }
455
456 /**
457  * Apply filter in pitch-subframe steps.
458  *
459  * @param memory buffer for the previous state of the filter
460  *        - must be able to contain 303 elements
461  *        - the 143 first elements are from the previous state
462  *        - the next 160 are for output
463  * @param v_in input filter vector
464  * @param gain per-subframe gain array, each element is between 0.0 and 2.0
465  * @param lag per-subframe lag array, each element is
466  *        - between 16 and 143 if its corresponding pfrac is 0,
467  *        - between 16 and 139 otherwise
468  * @param pfrac per-subframe boolean array, 1 if the lag is fractional, 0
469  *        otherwise
470  *
471  * @return filter output vector
472  */
473 static const float *do_pitchfilter(float memory[303], const float v_in[160],
474                                    const float gain[4], const uint8_t *lag,
475                                    const uint8_t pfrac[4])
476 {
477     int         i, j;
478     float       *v_lag, *v_out;
479     const float *v_len;
480
481     v_out = memory + 143; // Output vector starts at memory[143].
482
483     for(i=0; i<4; i++)
484     {
485         if(gain[i])
486         {
487             v_lag = memory + 143 + 40 * i - lag[i];
488             for(v_len=v_in+40; v_in<v_len; v_in++)
489             {
490                 if(pfrac[i]) // If it is a fractional lag...
491                 {
492                     for(j=0, *v_out=0.; j<4; j++)
493                         *v_out += qcelp_hammsinc_table[j] * (v_lag[j-4] + v_lag[3-j]);
494                 }else
495                     *v_out = *v_lag;
496
497                 *v_out = *v_in + gain[i] * *v_out;
498
499                 v_lag++;
500                 v_out++;
501             }
502         }else
503         {
504             memcpy(v_out, v_in, 40 * sizeof(float));
505             v_in  += 40;
506             v_out += 40;
507         }
508     }
509
510     memmove(memory, memory + 160, 143 * sizeof(float));
511     return memory + 143;
512 }
513
514 /**
515  * Apply pitch synthesis filter and pitch prefilter to the scaled codebook vector.
516  * TIA/EIA/IS-733 2.4.5.2, 2.4.8.7.2
517  *
518  * @param q the context
519  * @param cdn_vector the scaled codebook vector
520  */
521 static void apply_pitch_filters(QCELPContext *q, float *cdn_vector)
522 {
523     int         i;
524     const float *v_synthesis_filtered, *v_pre_filtered;
525
526     if(q->bitrate >= RATE_HALF ||
527        q->bitrate == SILENCE ||
528        (q->bitrate == I_F_Q && (q->prev_bitrate >= RATE_HALF)))
529     {
530
531         if(q->bitrate >= RATE_HALF)
532         {
533
534             // Compute gain & lag for the whole frame.
535             for(i=0; i<4; i++)
536             {
537                 q->pitch_gain[i] = q->frame.plag[i] ? (q->frame.pgain[i] + 1) * 0.25 : 0.0;
538
539                 q->pitch_lag[i] = q->frame.plag[i] + 16;
540             }
541         }else
542         {
543             float max_pitch_gain;
544
545             if (q->bitrate == I_F_Q)
546             {
547                   if (q->erasure_count < 3)
548                       max_pitch_gain = 0.9 - 0.3 * (q->erasure_count - 1);
549                   else
550                       max_pitch_gain = 0.0;
551             }else
552             {
553                 assert(q->bitrate == SILENCE);
554                 max_pitch_gain = 1.0;
555             }
556             for(i=0; i<4; i++)
557                 q->pitch_gain[i] = FFMIN(q->pitch_gain[i], max_pitch_gain);
558
559             memset(q->frame.pfrac, 0, sizeof(q->frame.pfrac));
560         }
561
562         // pitch synthesis filter
563         v_synthesis_filtered = do_pitchfilter(q->pitch_synthesis_filter_mem,
564                                               cdn_vector, q->pitch_gain,
565                                               q->pitch_lag, q->frame.pfrac);
566
567         // pitch prefilter update
568         for(i=0; i<4; i++)
569             q->pitch_gain[i] = 0.5 * FFMIN(q->pitch_gain[i], 1.0);
570
571         v_pre_filtered = do_pitchfilter(q->pitch_pre_filter_mem,
572                                         v_synthesis_filtered,
573                                         q->pitch_gain, q->pitch_lag,
574                                         q->frame.pfrac);
575
576         apply_gain_ctrl(cdn_vector, v_synthesis_filtered, v_pre_filtered);
577     }else
578     {
579         memcpy(q->pitch_synthesis_filter_mem, cdn_vector + 17,
580                143 * sizeof(float));
581         memcpy(q->pitch_pre_filter_mem, cdn_vector + 17, 143 * sizeof(float));
582         memset(q->pitch_gain, 0, sizeof(q->pitch_gain));
583         memset(q->pitch_lag,  0, sizeof(q->pitch_lag));
584     }
585 }
586
587 /**
588  * Interpolates LSP frequencies and computes LPC coefficients
589  * for a given bitrate & pitch subframe.
590  *
591  * TIA/EIA/IS-733 2.4.3.3.4, 2.4.8.7.2
592  *
593  * @param q the context
594  * @param curr_lspf LSP frequencies vector of the current frame
595  * @param lpc float vector for the resulting LPC
596  * @param subframe_num frame number in decoded stream
597  */
598 void interpolate_lpc(QCELPContext *q, const float *curr_lspf, float *lpc,
599                      const int subframe_num)
600 {
601     float interpolated_lspf[10];
602     float weight;
603
604     if(q->bitrate >= RATE_QUARTER)
605         weight = 0.25 * (subframe_num + 1);
606     else if(q->bitrate == RATE_OCTAVE && !subframe_num)
607         weight = 0.625;
608     else
609         weight = 1.0;
610
611     if(weight != 1.0)
612     {
613         weighted_vector_sumf(interpolated_lspf, curr_lspf, q->prev_lspf,
614                              weight, 1.0 - weight, 10);
615         ff_qcelp_lspf2lpc(interpolated_lspf, lpc);
616     }else if(q->bitrate >= RATE_QUARTER ||
617              (q->bitrate == I_F_Q && !subframe_num))
618         ff_qcelp_lspf2lpc(curr_lspf, lpc);
619     else if(q->bitrate == SILENCE && !subframe_num)
620         ff_qcelp_lspf2lpc(q->prev_lspf, lpc);
621 }
622
623 static qcelp_packet_rate buf_size2bitrate(const int buf_size)
624 {
625     switch(buf_size)
626     {
627         case 35: return RATE_FULL;
628         case 17: return RATE_HALF;
629         case  8: return RATE_QUARTER;
630         case  4: return RATE_OCTAVE;
631         case  1: return SILENCE;
632     }
633
634     return I_F_Q;
635 }
636
637 /**
638  * Determine the bitrate from the frame size and/or the first byte of the frame.
639  *
640  * @param avctx the AV codec context
641  * @param buf_size length of the buffer
642  * @param buf the bufffer
643  *
644  * @return the bitrate on success,
645  *         I_F_Q  if the bitrate cannot be satisfactorily determined
646  *
647  * TIA/EIA/IS-733 2.4.8.7.1
648  */
649 static qcelp_packet_rate determine_bitrate(AVCodecContext *avctx, const int buf_size,
650                              const uint8_t **buf)
651 {
652     qcelp_packet_rate bitrate;
653
654     if((bitrate = buf_size2bitrate(buf_size)) >= 0)
655     {
656         if(bitrate > **buf)
657         {
658             QCELPContext *q = avctx->priv_data;
659             if (!q->warned_buf_mismatch_bitrate)
660             {
661             av_log(avctx, AV_LOG_WARNING,
662                    "Claimed bitrate and buffer size mismatch.\n");
663                 q->warned_buf_mismatch_bitrate = 1;
664             }
665             bitrate = **buf;
666         }else if(bitrate < **buf)
667         {
668             av_log(avctx, AV_LOG_ERROR,
669                    "Buffer is too small for the claimed bitrate.\n");
670             return I_F_Q;
671         }
672         (*buf)++;
673     }else if((bitrate = buf_size2bitrate(buf_size + 1)) >= 0)
674     {
675         av_log(avctx, AV_LOG_WARNING,
676                "Bitrate byte is missing, guessing the bitrate from packet size.\n");
677     }else
678         return I_F_Q;
679
680     if(bitrate == SILENCE)
681     {
682         //FIXME: Remove experimental warning when tested with samples.
683         ff_log_ask_for_sample(avctx, "'Blank frame handling is experimental.");
684     }
685     return bitrate;
686 }
687
688 static void warn_insufficient_frame_quality(AVCodecContext *avctx,
689                                             const char *message)
690 {
691     av_log(avctx, AV_LOG_WARNING, "Frame #%d, IFQ: %s\n", avctx->frame_number,
692            message);
693 }
694
695 static int qcelp_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
696                               const uint8_t *buf, int buf_size)
697 {
698     QCELPContext *q = avctx->priv_data;
699     float *outbuffer = data;
700     int   i;
701     float quantized_lspf[10], lpc[10];
702     float gain[16];
703     float *formant_mem;
704
705     if((q->bitrate = determine_bitrate(avctx, buf_size, &buf)) == I_F_Q)
706     {
707         warn_insufficient_frame_quality(avctx, "bitrate cannot be determined.");
708         goto erasure;
709     }
710
711     if(q->bitrate == RATE_OCTAVE &&
712        (q->first16bits = AV_RB16(buf)) == 0xFFFF)
713     {
714         warn_insufficient_frame_quality(avctx, "Bitrate is 1/8 and first 16 bits are on.");
715         goto erasure;
716     }
717
718     if(q->bitrate > SILENCE)
719     {
720         const QCELPBitmap *bitmaps     = qcelp_unpacking_bitmaps_per_rate[q->bitrate];
721         const QCELPBitmap *bitmaps_end = qcelp_unpacking_bitmaps_per_rate[q->bitrate]
722                                        + qcelp_unpacking_bitmaps_lengths[q->bitrate];
723         uint8_t           *unpacked_data = (uint8_t *)&q->frame;
724
725         init_get_bits(&q->gb, buf, 8*buf_size);
726
727         memset(&q->frame, 0, sizeof(QCELPFrame));
728
729         for(; bitmaps < bitmaps_end; bitmaps++)
730             unpacked_data[bitmaps->index] |= get_bits(&q->gb, bitmaps->bitlen) << bitmaps->bitpos;
731
732         // Check for erasures/blanks on rates 1, 1/4 and 1/8.
733         if(q->frame.reserved)
734         {
735             warn_insufficient_frame_quality(avctx, "Wrong data in reserved frame area.");
736             goto erasure;
737         }
738         if(q->bitrate == RATE_QUARTER &&
739            codebook_sanity_check_for_rate_quarter(q->frame.cbgain))
740         {
741             warn_insufficient_frame_quality(avctx, "Codebook gain sanity check failed.");
742             goto erasure;
743         }
744
745         if(q->bitrate >= RATE_HALF)
746         {
747             for(i=0; i<4; i++)
748             {
749                 if(q->frame.pfrac[i] && q->frame.plag[i] >= 124)
750                 {
751                     warn_insufficient_frame_quality(avctx, "Cannot initialize pitch filter.");
752                     goto erasure;
753                 }
754             }
755         }
756     }
757
758     decode_gain_and_index(q, gain);
759     compute_svector(q, gain, outbuffer);
760
761     if(decode_lspf(q, quantized_lspf) < 0)
762     {
763         warn_insufficient_frame_quality(avctx, "Badly received packets in frame.");
764         goto erasure;
765     }
766
767
768     apply_pitch_filters(q, outbuffer);
769
770     if(q->bitrate == I_F_Q)
771     {
772 erasure:
773         q->bitrate = I_F_Q;
774         q->erasure_count++;
775         decode_gain_and_index(q, gain);
776         compute_svector(q, gain, outbuffer);
777         decode_lspf(q, quantized_lspf);
778         apply_pitch_filters(q, outbuffer);
779     }else
780         q->erasure_count = 0;
781
782     formant_mem = q->formant_mem + 10;
783     for(i=0; i<4; i++)
784     {
785         interpolate_lpc(q, quantized_lspf, lpc, i);
786         ff_celp_lp_synthesis_filterf(formant_mem, lpc, outbuffer + i * 40, 40,
787                                      10);
788         formant_mem += 40;
789     }
790     memcpy(q->formant_mem, q->formant_mem + 160, 10 * sizeof(float));
791
792     // FIXME: postfilter and final gain control should be here.
793     // TIA/EIA/IS-733 2.4.8.6
794
795     formant_mem = q->formant_mem + 10;
796     for(i=0; i<160; i++)
797         *outbuffer++ = av_clipf(*formant_mem++, QCELP_CLIP_LOWER_BOUND,
798                                 QCELP_CLIP_UPPER_BOUND);
799
800     memcpy(q->prev_lspf, quantized_lspf, sizeof(q->prev_lspf));
801     q->prev_bitrate = q->bitrate;
802
803     *data_size = 160 * sizeof(*outbuffer);
804
805     return *data_size;
806 }
807
808 AVCodec qcelp_decoder =
809 {
810     .name   = "qcelp",
811     .type   = CODEC_TYPE_AUDIO,
812     .id     = CODEC_ID_QCELP,
813     .init   = qcelp_decode_init,
814     .decode = qcelp_decode_frame,
815     .priv_data_size = sizeof(QCELPContext),
816     .long_name = NULL_IF_CONFIG_SMALL("QCELP / PureVoice"),
817 };