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