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1 /*
2  * SIPR / ACELP.NET decoder
3  *
4  * Copyright (c) 2008 Vladimir Voroshilov
5  * Copyright (c) 2009 Vitor Sessak
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 #include <math.h>
25 #include <stdint.h>
26 #include <string.h>
27 
28 #include "libavutil/channel_layout.h"
29 #include "libavutil/float_dsp.h"
30 #include "libavutil/mathematics.h"
31 
32 #define BITSTREAM_READER_LE
33 #include "avcodec.h"
34 #include "codec_internal.h"
35 #include "get_bits.h"
36 #include "internal.h"
37 #include "lsp.h"
38 #include "acelp_vectors.h"
39 #include "acelp_pitch_delay.h"
40 #include "acelp_filters.h"
41 #include "celp_filters.h"
42 
43 #define MAX_SUBFRAME_COUNT   5
44 
45 #include "sipr.h"
46 #include "siprdata.h"
47 
48 typedef struct SiprModeParam {
49     const char *mode_name;
50     uint16_t bits_per_frame;
51     uint8_t subframe_count;
52     uint8_t frames_per_packet;
53     float pitch_sharp_factor;
54 
55     /* bitstream parameters */
56     uint8_t number_of_fc_indexes;
57     uint8_t ma_predictor_bits;  ///< size in bits of the switched MA predictor
58 
59     /** size in bits of the i-th stage vector of quantizer */
60     uint8_t vq_indexes_bits[5];
61 
62     /** size in bits of the adaptive-codebook index for every subframe */
63     uint8_t pitch_delay_bits[5];
64 
65     uint8_t gp_index_bits;
66     uint8_t fc_index_bits[10]; ///< size in bits of the fixed codebook indexes
67     uint8_t gc_index_bits;     ///< size in bits of the gain  codebook indexes
68 } SiprModeParam;
69 
70 static const SiprModeParam modes[MODE_COUNT] = {
71     [MODE_16k] = {
72         .mode_name          = "16k",
73         .bits_per_frame     = 160,
74         .subframe_count     = SUBFRAME_COUNT_16k,
75         .frames_per_packet  = 1,
76         .pitch_sharp_factor = 0.00,
77 
78         .number_of_fc_indexes = 10,
79         .ma_predictor_bits    = 1,
80         .vq_indexes_bits      = {7, 8, 7, 7, 7},
81         .pitch_delay_bits     = {9, 6},
82         .gp_index_bits        = 4,
83         .fc_index_bits        = {4, 5, 4, 5, 4, 5, 4, 5, 4, 5},
84         .gc_index_bits        = 5
85     },
86 
87     [MODE_8k5] = {
88         .mode_name          = "8k5",
89         .bits_per_frame     = 152,
90         .subframe_count     = 3,
91         .frames_per_packet  = 1,
92         .pitch_sharp_factor = 0.8,
93 
94         .number_of_fc_indexes = 3,
95         .ma_predictor_bits    = 0,
96         .vq_indexes_bits      = {6, 7, 7, 7, 5},
97         .pitch_delay_bits     = {8, 5, 5},
98         .gp_index_bits        = 0,
99         .fc_index_bits        = {9, 9, 9},
100         .gc_index_bits        = 7
101     },
102 
103     [MODE_6k5] = {
104         .mode_name          = "6k5",
105         .bits_per_frame     = 232,
106         .subframe_count     = 3,
107         .frames_per_packet  = 2,
108         .pitch_sharp_factor = 0.8,
109 
110         .number_of_fc_indexes = 3,
111         .ma_predictor_bits    = 0,
112         .vq_indexes_bits      = {6, 7, 7, 7, 5},
113         .pitch_delay_bits     = {8, 5, 5},
114         .gp_index_bits        = 0,
115         .fc_index_bits        = {5, 5, 5},
116         .gc_index_bits        = 7
117     },
118 
119     [MODE_5k0] = {
120         .mode_name          = "5k0",
121         .bits_per_frame     = 296,
122         .subframe_count     = 5,
123         .frames_per_packet  = 2,
124         .pitch_sharp_factor = 0.85,
125 
126         .number_of_fc_indexes = 1,
127         .ma_predictor_bits    = 0,
128         .vq_indexes_bits      = {6, 7, 7, 7, 5},
129         .pitch_delay_bits     = {8, 5, 8, 5, 5},
130         .gp_index_bits        = 0,
131         .fc_index_bits        = {10},
132         .gc_index_bits        = 7
133     }
134 };
135 
136 const float ff_pow_0_5[] = {
137     1.0/(1 <<  1), 1.0/(1 <<  2), 1.0/(1 <<  3), 1.0/(1 <<  4),
138     1.0/(1 <<  5), 1.0/(1 <<  6), 1.0/(1 <<  7), 1.0/(1 <<  8),
139     1.0/(1 <<  9), 1.0/(1 << 10), 1.0/(1 << 11), 1.0/(1 << 12),
140     1.0/(1 << 13), 1.0/(1 << 14), 1.0/(1 << 15), 1.0/(1 << 16)
141 };
142 
dequant(float * out,const int * idx,const float * const cbs[])143 static void dequant(float *out, const int *idx, const float * const cbs[])
144 {
145     int i;
146     int stride  = 2;
147     int num_vec = 5;
148 
149     for (i = 0; i < num_vec; i++)
150         memcpy(out + stride*i, cbs[i] + stride*idx[i], stride*sizeof(float));
151 
152 }
153 
lsf_decode_fp(float * lsfnew,float * lsf_history,const SiprParameters * parm)154 static void lsf_decode_fp(float *lsfnew, float *lsf_history,
155                           const SiprParameters *parm)
156 {
157     int i;
158     float lsf_tmp[LP_FILTER_ORDER];
159 
160     dequant(lsf_tmp, parm->vq_indexes, lsf_codebooks);
161 
162     for (i = 0; i < LP_FILTER_ORDER; i++)
163         lsfnew[i] = lsf_history[i] * 0.33 + lsf_tmp[i] + mean_lsf[i];
164 
165     ff_sort_nearly_sorted_floats(lsfnew, LP_FILTER_ORDER - 1);
166 
167     /* Note that a minimum distance is not enforced between the last value and
168        the previous one, contrary to what is done in ff_acelp_reorder_lsf() */
169     ff_set_min_dist_lsf(lsfnew, LSFQ_DIFF_MIN, LP_FILTER_ORDER - 1);
170     lsfnew[9] = FFMIN(lsfnew[LP_FILTER_ORDER - 1], 1.3 * M_PI);
171 
172     memcpy(lsf_history, lsf_tmp, LP_FILTER_ORDER * sizeof(*lsf_history));
173 
174     for (i = 0; i < LP_FILTER_ORDER - 1; i++)
175         lsfnew[i] = cos(lsfnew[i]);
176     lsfnew[LP_FILTER_ORDER - 1] *= 6.153848 / M_PI;
177 }
178 
179 /** Apply pitch lag to the fixed vector (AMR section 6.1.2). */
pitch_sharpening(int pitch_lag_int,float beta,float * fixed_vector)180 static void pitch_sharpening(int pitch_lag_int, float beta,
181                              float *fixed_vector)
182 {
183     int i;
184 
185     for (i = pitch_lag_int; i < SUBFR_SIZE; i++)
186         fixed_vector[i] += beta * fixed_vector[i - pitch_lag_int];
187 }
188 
189 /**
190  * Extract decoding parameters from the input bitstream.
191  * @param parms          parameters structure
192  * @param pgb            pointer to initialized GetBitContext structure
193  */
decode_parameters(SiprParameters * parms,GetBitContext * pgb,const SiprModeParam * p)194 static void decode_parameters(SiprParameters* parms, GetBitContext *pgb,
195                               const SiprModeParam *p)
196 {
197     int i, j;
198 
199     if (p->ma_predictor_bits)
200         parms->ma_pred_switch       = get_bits(pgb, p->ma_predictor_bits);
201 
202     for (i = 0; i < 5; i++)
203         parms->vq_indexes[i]        = get_bits(pgb, p->vq_indexes_bits[i]);
204 
205     for (i = 0; i < p->subframe_count; i++) {
206         parms->pitch_delay[i]       = get_bits(pgb, p->pitch_delay_bits[i]);
207         if (p->gp_index_bits)
208             parms->gp_index[i]      = get_bits(pgb, p->gp_index_bits);
209 
210         for (j = 0; j < p->number_of_fc_indexes; j++)
211             parms->fc_indexes[i][j] = get_bits(pgb, p->fc_index_bits[j]);
212 
213         parms->gc_index[i]          = get_bits(pgb, p->gc_index_bits);
214     }
215 }
216 
sipr_decode_lp(float * lsfnew,const float * lsfold,float * Az,int num_subfr)217 static void sipr_decode_lp(float *lsfnew, const float *lsfold, float *Az,
218                            int num_subfr)
219 {
220     double lsfint[LP_FILTER_ORDER];
221     int i,j;
222     float t, t0 = 1.0 / num_subfr;
223 
224     t = t0 * 0.5;
225     for (i = 0; i < num_subfr; i++) {
226         for (j = 0; j < LP_FILTER_ORDER; j++)
227             lsfint[j] = lsfold[j] * (1 - t) + t * lsfnew[j];
228 
229         ff_amrwb_lsp2lpc(lsfint, Az, LP_FILTER_ORDER);
230         Az += LP_FILTER_ORDER;
231         t += t0;
232     }
233 }
234 
235 /**
236  * Evaluate the adaptive impulse response.
237  */
eval_ir(const float * Az,int pitch_lag,float * freq,float pitch_sharp_factor)238 static void eval_ir(const float *Az, int pitch_lag, float *freq,
239                     float pitch_sharp_factor)
240 {
241     float tmp1[SUBFR_SIZE+1], tmp2[LP_FILTER_ORDER+1];
242     int i;
243 
244     tmp1[0] = 1.0;
245     for (i = 0; i < LP_FILTER_ORDER; i++) {
246         tmp1[i+1] = Az[i] * ff_pow_0_55[i];
247         tmp2[i  ] = Az[i] * ff_pow_0_7 [i];
248     }
249     memset(tmp1 + 11, 0, 37 * sizeof(float));
250 
251     ff_celp_lp_synthesis_filterf(freq, tmp2, tmp1, SUBFR_SIZE,
252                                  LP_FILTER_ORDER);
253 
254     pitch_sharpening(pitch_lag, pitch_sharp_factor, freq);
255 }
256 
257 /**
258  * Evaluate the convolution of a vector with a sparse vector.
259  */
convolute_with_sparse(float * out,const AMRFixed * pulses,const float * shape,int length)260 static void convolute_with_sparse(float *out, const AMRFixed *pulses,
261                                   const float *shape, int length)
262 {
263     int i, j;
264 
265     memset(out, 0, length*sizeof(float));
266     for (i = 0; i < pulses->n; i++)
267         for (j = pulses->x[i]; j < length; j++)
268             out[j] += pulses->y[i] * shape[j - pulses->x[i]];
269 }
270 
271 /**
272  * Apply postfilter, very similar to AMR one.
273  */
postfilter_5k0(SiprContext * ctx,const float * lpc,float * samples)274 static void postfilter_5k0(SiprContext *ctx, const float *lpc, float *samples)
275 {
276     float buf[SUBFR_SIZE + LP_FILTER_ORDER];
277     float *pole_out = buf + LP_FILTER_ORDER;
278     float lpc_n[LP_FILTER_ORDER];
279     float lpc_d[LP_FILTER_ORDER];
280     int i;
281 
282     for (i = 0; i < LP_FILTER_ORDER; i++) {
283         lpc_d[i] = lpc[i] * ff_pow_0_75[i];
284         lpc_n[i] = lpc[i] * ff_pow_0_5 [i];
285     };
286 
287     memcpy(pole_out - LP_FILTER_ORDER, ctx->postfilter_mem,
288            LP_FILTER_ORDER*sizeof(float));
289 
290     ff_celp_lp_synthesis_filterf(pole_out, lpc_d, samples, SUBFR_SIZE,
291                                  LP_FILTER_ORDER);
292 
293     memcpy(ctx->postfilter_mem, pole_out + SUBFR_SIZE - LP_FILTER_ORDER,
294            LP_FILTER_ORDER*sizeof(float));
295 
296     ff_tilt_compensation(&ctx->tilt_mem, 0.4, pole_out, SUBFR_SIZE);
297 
298     memcpy(pole_out - LP_FILTER_ORDER, ctx->postfilter_mem5k0,
299            LP_FILTER_ORDER*sizeof(*pole_out));
300 
301     memcpy(ctx->postfilter_mem5k0, pole_out + SUBFR_SIZE - LP_FILTER_ORDER,
302            LP_FILTER_ORDER*sizeof(*pole_out));
303 
304     ff_celp_lp_zero_synthesis_filterf(samples, lpc_n, pole_out, SUBFR_SIZE,
305                                       LP_FILTER_ORDER);
306 
307 }
308 
decode_fixed_sparse(AMRFixed * fixed_sparse,const int16_t * pulses,SiprMode mode,int low_gain)309 static void decode_fixed_sparse(AMRFixed *fixed_sparse, const int16_t *pulses,
310                                 SiprMode mode, int low_gain)
311 {
312     int i;
313 
314     switch (mode) {
315     case MODE_6k5:
316         for (i = 0; i < 3; i++) {
317             fixed_sparse->x[i] = 3 * (pulses[i] & 0xf) + i;
318             fixed_sparse->y[i] = pulses[i] & 0x10 ? -1 : 1;
319         }
320         fixed_sparse->n = 3;
321         break;
322     case MODE_8k5:
323         for (i = 0; i < 3; i++) {
324             fixed_sparse->x[2*i    ] = 3 * ((pulses[i] >> 4) & 0xf) + i;
325             fixed_sparse->x[2*i + 1] = 3 * ( pulses[i]       & 0xf) + i;
326 
327             fixed_sparse->y[2*i    ] = (pulses[i] & 0x100) ? -1.0: 1.0;
328 
329             fixed_sparse->y[2*i + 1] =
330                 (fixed_sparse->x[2*i + 1] < fixed_sparse->x[2*i]) ?
331                 -fixed_sparse->y[2*i    ] : fixed_sparse->y[2*i];
332         }
333 
334         fixed_sparse->n = 6;
335         break;
336     case MODE_5k0:
337     default:
338         if (low_gain) {
339             int offset = (pulses[0] & 0x200) ? 2 : 0;
340             int val = pulses[0];
341 
342             for (i = 0; i < 3; i++) {
343                 int index = (val & 0x7) * 6 + 4 - i*2;
344 
345                 fixed_sparse->y[i] = (offset + index) & 0x3 ? -1 : 1;
346                 fixed_sparse->x[i] = index;
347 
348                 val >>= 3;
349             }
350             fixed_sparse->n = 3;
351         } else {
352             int pulse_subset = (pulses[0] >> 8) & 1;
353 
354             fixed_sparse->x[0] = ((pulses[0] >> 4) & 15) * 3 + pulse_subset;
355             fixed_sparse->x[1] = ( pulses[0]       & 15) * 3 + pulse_subset + 1;
356 
357             fixed_sparse->y[0] = pulses[0] & 0x200 ? -1 : 1;
358             fixed_sparse->y[1] = -fixed_sparse->y[0];
359             fixed_sparse->n = 2;
360         }
361         break;
362     }
363 }
364 
decode_frame(SiprContext * ctx,SiprParameters * params,float * out_data)365 static void decode_frame(SiprContext *ctx, SiprParameters *params,
366                          float *out_data)
367 {
368     int i, j;
369     int subframe_count = modes[ctx->mode].subframe_count;
370     int frame_size = subframe_count * SUBFR_SIZE;
371     float Az[LP_FILTER_ORDER * MAX_SUBFRAME_COUNT];
372     float *excitation;
373     float ir_buf[SUBFR_SIZE + LP_FILTER_ORDER];
374     float lsf_new[LP_FILTER_ORDER];
375     float *impulse_response = ir_buf + LP_FILTER_ORDER;
376     float *synth = ctx->synth_buf + 16; // 16 instead of LP_FILTER_ORDER for
377                                         // memory alignment
378     int t0_first = 0;
379     AMRFixed fixed_cb;
380 
381     memset(ir_buf, 0, LP_FILTER_ORDER * sizeof(float));
382     lsf_decode_fp(lsf_new, ctx->lsf_history, params);
383 
384     sipr_decode_lp(lsf_new, ctx->lsp_history, Az, subframe_count);
385 
386     memcpy(ctx->lsp_history, lsf_new, LP_FILTER_ORDER * sizeof(float));
387 
388     excitation = ctx->excitation + PITCH_DELAY_MAX + L_INTERPOL;
389 
390     for (i = 0; i < subframe_count; i++) {
391         float *pAz = Az + i*LP_FILTER_ORDER;
392         float fixed_vector[SUBFR_SIZE];
393         int T0,T0_frac;
394         float pitch_gain, gain_code, avg_energy;
395 
396         ff_decode_pitch_lag(&T0, &T0_frac, params->pitch_delay[i], t0_first, i,
397                             ctx->mode == MODE_5k0, 6);
398 
399         if (i == 0 || (i == 2 && ctx->mode == MODE_5k0))
400             t0_first = T0;
401 
402         ff_acelp_interpolatef(excitation, excitation - T0 + (T0_frac <= 0),
403                               ff_b60_sinc, 6,
404                               2 * ((2 + T0_frac)%3 + 1), LP_FILTER_ORDER,
405                               SUBFR_SIZE);
406 
407         decode_fixed_sparse(&fixed_cb, params->fc_indexes[i], ctx->mode,
408                             ctx->past_pitch_gain < 0.8);
409 
410         eval_ir(pAz, T0, impulse_response, modes[ctx->mode].pitch_sharp_factor);
411 
412         convolute_with_sparse(fixed_vector, &fixed_cb, impulse_response,
413                               SUBFR_SIZE);
414 
415         avg_energy = (0.01 + avpriv_scalarproduct_float_c(fixed_vector,
416                                                           fixed_vector,
417                                                           SUBFR_SIZE)) /
418                      SUBFR_SIZE;
419 
420         ctx->past_pitch_gain = pitch_gain = gain_cb[params->gc_index[i]][0];
421 
422         gain_code = ff_amr_set_fixed_gain(gain_cb[params->gc_index[i]][1],
423                                           avg_energy, ctx->energy_history,
424                                           34 - 15.0/(0.05*M_LN10/M_LN2),
425                                           pred);
426 
427         ff_weighted_vector_sumf(excitation, excitation, fixed_vector,
428                                 pitch_gain, gain_code, SUBFR_SIZE);
429 
430         pitch_gain *= 0.5 * pitch_gain;
431         pitch_gain = FFMIN(pitch_gain, 0.4);
432 
433         ctx->gain_mem = 0.7 * ctx->gain_mem + 0.3 * pitch_gain;
434         ctx->gain_mem = FFMIN(ctx->gain_mem, pitch_gain);
435         gain_code *= ctx->gain_mem;
436 
437         for (j = 0; j < SUBFR_SIZE; j++)
438             fixed_vector[j] = excitation[j] - gain_code * fixed_vector[j];
439 
440         if (ctx->mode == MODE_5k0) {
441             postfilter_5k0(ctx, pAz, fixed_vector);
442 
443             ff_celp_lp_synthesis_filterf(ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i*SUBFR_SIZE,
444                                          pAz, excitation, SUBFR_SIZE,
445                                          LP_FILTER_ORDER);
446         }
447 
448         ff_celp_lp_synthesis_filterf(synth + i*SUBFR_SIZE, pAz, fixed_vector,
449                                      SUBFR_SIZE, LP_FILTER_ORDER);
450 
451         excitation += SUBFR_SIZE;
452     }
453 
454     memcpy(synth - LP_FILTER_ORDER, synth + frame_size - LP_FILTER_ORDER,
455            LP_FILTER_ORDER * sizeof(float));
456 
457     if (ctx->mode == MODE_5k0) {
458         for (i = 0; i < subframe_count; i++) {
459             float energy = avpriv_scalarproduct_float_c(ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i * SUBFR_SIZE,
460                                                         ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i * SUBFR_SIZE,
461                                                         SUBFR_SIZE);
462             ff_adaptive_gain_control(&synth[i * SUBFR_SIZE],
463                                      &synth[i * SUBFR_SIZE], energy,
464                                      SUBFR_SIZE, 0.9, &ctx->postfilter_agc);
465         }
466 
467         memcpy(ctx->postfilter_syn5k0, ctx->postfilter_syn5k0 + frame_size,
468                LP_FILTER_ORDER*sizeof(float));
469     }
470     memmove(ctx->excitation, excitation - PITCH_DELAY_MAX - L_INTERPOL,
471            (PITCH_DELAY_MAX + L_INTERPOL) * sizeof(float));
472 
473     ff_acelp_apply_order_2_transfer_function(out_data, synth,
474                                              (const float[2]) {-1.99997   , 1.000000000},
475                                              (const float[2]) {-1.93307352, 0.935891986},
476                                              0.939805806,
477                                              ctx->highpass_filt_mem,
478                                              frame_size);
479 }
480 
sipr_decoder_init(AVCodecContext * avctx)481 static av_cold int sipr_decoder_init(AVCodecContext * avctx)
482 {
483     SiprContext *ctx = avctx->priv_data;
484     int i;
485 
486     switch (avctx->block_align) {
487     case 20: ctx->mode = MODE_16k; break;
488     case 19: ctx->mode = MODE_8k5; break;
489     case 29: ctx->mode = MODE_6k5; break;
490     case 37: ctx->mode = MODE_5k0; break;
491     default:
492         if      (avctx->bit_rate > 12200) ctx->mode = MODE_16k;
493         else if (avctx->bit_rate > 7500 ) ctx->mode = MODE_8k5;
494         else if (avctx->bit_rate > 5750 ) ctx->mode = MODE_6k5;
495         else                              ctx->mode = MODE_5k0;
496         av_log(avctx, AV_LOG_WARNING,
497                "Invalid block_align: %d. Mode %s guessed based on bitrate: %"PRId64"\n",
498                avctx->block_align, modes[ctx->mode].mode_name, avctx->bit_rate);
499     }
500 
501     av_log(avctx, AV_LOG_DEBUG, "Mode: %s\n", modes[ctx->mode].mode_name);
502 
503     if (ctx->mode == MODE_16k) {
504         ff_sipr_init_16k(ctx);
505         ctx->decode_frame = ff_sipr_decode_frame_16k;
506     } else {
507         ctx->decode_frame = decode_frame;
508     }
509 
510     for (i = 0; i < LP_FILTER_ORDER; i++)
511         ctx->lsp_history[i] = cos((i+1) * M_PI / (LP_FILTER_ORDER + 1));
512 
513     for (i = 0; i < 4; i++)
514         ctx->energy_history[i] = -14;
515 
516     av_channel_layout_uninit(&avctx->ch_layout);
517     avctx->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
518     avctx->sample_fmt     = AV_SAMPLE_FMT_FLT;
519 
520     return 0;
521 }
522 
sipr_decode_frame(AVCodecContext * avctx,AVFrame * frame,int * got_frame_ptr,AVPacket * avpkt)523 static int sipr_decode_frame(AVCodecContext *avctx, AVFrame *frame,
524                              int *got_frame_ptr, AVPacket *avpkt)
525 {
526     SiprContext *ctx = avctx->priv_data;
527     const uint8_t *buf=avpkt->data;
528     SiprParameters parm;
529     const SiprModeParam *mode_par = &modes[ctx->mode];
530     GetBitContext gb;
531     float *samples;
532     int subframe_size = ctx->mode == MODE_16k ? L_SUBFR_16k : SUBFR_SIZE;
533     int i, ret;
534 
535     ctx->avctx = avctx;
536     if (avpkt->size < (mode_par->bits_per_frame >> 3)) {
537         av_log(avctx, AV_LOG_ERROR,
538                "Error processing packet: packet size (%d) too small\n",
539                avpkt->size);
540         return AVERROR_INVALIDDATA;
541     }
542 
543     /* get output buffer */
544     frame->nb_samples = mode_par->frames_per_packet * subframe_size *
545                         mode_par->subframe_count;
546     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
547         return ret;
548     samples = (float *)frame->data[0];
549 
550     init_get_bits(&gb, buf, mode_par->bits_per_frame);
551 
552     for (i = 0; i < mode_par->frames_per_packet; i++) {
553         decode_parameters(&parm, &gb, mode_par);
554 
555         ctx->decode_frame(ctx, &parm, samples);
556 
557         samples += subframe_size * mode_par->subframe_count;
558     }
559 
560     *got_frame_ptr = 1;
561 
562     return mode_par->bits_per_frame >> 3;
563 }
564 
565 const FFCodec ff_sipr_decoder = {
566     .p.name         = "sipr",
567     .p.long_name    = NULL_IF_CONFIG_SMALL("RealAudio SIPR / ACELP.NET"),
568     .p.type         = AVMEDIA_TYPE_AUDIO,
569     .p.id           = AV_CODEC_ID_SIPR,
570     .priv_data_size = sizeof(SiprContext),
571     .init           = sipr_decoder_init,
572     FF_CODEC_DECODE_CB(sipr_decode_frame),
573     .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
574     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
575 };
576