1/*
2 *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#include "webrtc_cng.h"
12
13#include <string.h>
14#include <stdlib.h>
15
16#include "cng_helpfuns.h"
17#include "signal_processing_library.h"
18
19typedef struct WebRtcCngDecInst_t_ {
20  uint32_t dec_seed;
21  int32_t dec_target_energy;
22  int32_t dec_used_energy;
23  int16_t dec_target_reflCoefs[WEBRTC_CNG_MAX_LPC_ORDER + 1];
24  int16_t dec_used_reflCoefs[WEBRTC_CNG_MAX_LPC_ORDER + 1];
25  int16_t dec_filtstate[WEBRTC_CNG_MAX_LPC_ORDER + 1];
26  int16_t dec_filtstateLow[WEBRTC_CNG_MAX_LPC_ORDER + 1];
27  int16_t dec_Efiltstate[WEBRTC_CNG_MAX_LPC_ORDER + 1];
28  int16_t dec_EfiltstateLow[WEBRTC_CNG_MAX_LPC_ORDER + 1];
29  int16_t dec_order;
30  int16_t dec_target_scale_factor;  /* Q29 */
31  int16_t dec_used_scale_factor;  /* Q29 */
32  int16_t target_scale_factor;  /* Q13 */
33  int16_t errorcode;
34  int16_t initflag;
35} WebRtcCngDecInst_t;
36
37typedef struct WebRtcCngEncInst_t_ {
38  int16_t enc_nrOfCoefs;
39  uint16_t enc_sampfreq;
40  int16_t enc_interval;
41  int16_t enc_msSinceSID;
42  int32_t enc_Energy;
43  int16_t enc_reflCoefs[WEBRTC_CNG_MAX_LPC_ORDER + 1];
44  int32_t enc_corrVector[WEBRTC_CNG_MAX_LPC_ORDER + 1];
45  uint32_t enc_seed;
46  int16_t errorcode;
47  int16_t initflag;
48} WebRtcCngEncInst_t;
49
50const int32_t WebRtcCng_kDbov[94] = {
51  1081109975,  858756178,  682134279,  541838517,  430397633,  341876992,
52  271562548,  215709799,  171344384,  136103682,  108110997,   85875618,
53  68213428,   54183852,   43039763,   34187699,   27156255,   21570980,
54  17134438,   13610368,   10811100,    8587562,    6821343,    5418385,
55  4303976,    3418770,    2715625,    2157098,    1713444,    1361037,
56  1081110,     858756,     682134,     541839,     430398,     341877,
57  271563,     215710,     171344,     136104,     108111,      85876,
58  68213,      54184,      43040,      34188,      27156,      21571,
59  17134,      13610,      10811,       8588,       6821,       5418,
60  4304,       3419,       2716,       2157,       1713,       1361,
61  1081,        859,        682,        542,        430,        342,
62  272,        216,        171,        136,        108,         86,
63  68,         54,         43,         34,         27,         22,
64  17,         14,         11,          9,          7,          5,
65  4,          3,          3,          2,          2,           1,
66  1,          1,          1,          1
67};
68
69const int16_t WebRtcCng_kCorrWindow[WEBRTC_CNG_MAX_LPC_ORDER] = {
70  32702, 32636, 32570, 32505, 32439, 32374,
71  32309, 32244, 32179, 32114, 32049, 31985
72};
73
74/****************************************************************************
75 * WebRtcCng_CreateEnc/Dec(...)
76 *
77 * These functions create an instance to the specified structure
78 *
79 * Input:
80 *      - XXX_inst      : Pointer to created instance that should be created
81 *
82 * Return value         :  0 - Ok
83 *                        -1 - Error
84 */
85int16_t WebRtcCng_CreateEnc(CNG_enc_inst** cng_inst) {
86  if (cng_inst != NULL) {
87    *cng_inst = (CNG_enc_inst*) malloc(sizeof(WebRtcCngEncInst_t));
88    if (*cng_inst != NULL) {
89      (*(WebRtcCngEncInst_t**) cng_inst)->errorcode = 0;
90      (*(WebRtcCngEncInst_t**) cng_inst)->initflag = 0;
91
92      /* Needed to get the right function pointers in SPLIB. */
93      WebRtcSpl_Init();
94
95      return 0;
96    } else {
97      /* The memory could not be allocated. */
98      return -1;
99    }
100  } else {
101    /* The input pointer is invalid (NULL). */
102    return -1;
103  }
104}
105
106int16_t WebRtcCng_CreateDec(CNG_dec_inst** cng_inst) {
107  if (cng_inst != NULL ) {
108    *cng_inst = (CNG_dec_inst*) malloc(sizeof(WebRtcCngDecInst_t));
109    if (*cng_inst != NULL ) {
110      (*(WebRtcCngDecInst_t**) cng_inst)->errorcode = 0;
111      (*(WebRtcCngDecInst_t**) cng_inst)->initflag = 0;
112
113      /* Needed to get the right function pointers in SPLIB. */
114      WebRtcSpl_Init();
115
116      return 0;
117    } else {
118      /* The memory could not be allocated */
119      return -1;
120    }
121  } else {
122    /* The input pointer is invalid (NULL). */
123    return -1;
124  }
125}
126
127/****************************************************************************
128 * WebRtcCng_InitEnc/Dec(...)
129 *
130 * This function initializes a instance
131 *
132 * Input:
133 *    - cng_inst      : Instance that should be initialized
134 *
135 *    - fs            : 8000 for narrowband and 16000 for wideband
136 *    - interval      : generate SID data every interval ms
137 *    - quality       : TBD
138 *
139 * Output:
140 *    - cng_inst      : Initialized instance
141 *
142 * Return value       :  0 - Ok
143 *                      -1 - Error
144 */
145int16_t WebRtcCng_InitEnc(CNG_enc_inst* cng_inst, uint16_t fs, int16_t interval,
146                          int16_t quality) {
147  int i;
148  WebRtcCngEncInst_t* inst = (WebRtcCngEncInst_t*) cng_inst;
149  memset(inst, 0, sizeof(WebRtcCngEncInst_t));
150
151  /* Check LPC order */
152  if (quality > WEBRTC_CNG_MAX_LPC_ORDER || quality <= 0) {
153    inst->errorcode = CNG_DISALLOWED_LPC_ORDER;
154    return -1;
155  }
156
157  inst->enc_sampfreq = fs;
158  inst->enc_interval = interval;
159  inst->enc_nrOfCoefs = quality;
160  inst->enc_msSinceSID = 0;
161  inst->enc_seed = 7777;  /* For debugging only. */
162  inst->enc_Energy = 0;
163  for (i = 0; i < (WEBRTC_CNG_MAX_LPC_ORDER + 1); i++) {
164    inst->enc_reflCoefs[i] = 0;
165    inst->enc_corrVector[i] = 0;
166  }
167  inst->initflag = 1;
168
169  return 0;
170}
171
172int16_t WebRtcCng_InitDec(CNG_dec_inst* cng_inst) {
173  int i;
174
175  WebRtcCngDecInst_t* inst = (WebRtcCngDecInst_t*) cng_inst;
176
177  memset(inst, 0, sizeof(WebRtcCngDecInst_t));
178  inst->dec_seed = 7777;  /* For debugging only. */
179  inst->dec_order = 5;
180  inst->dec_target_scale_factor = 0;
181  inst->dec_used_scale_factor = 0;
182  for (i = 0; i < (WEBRTC_CNG_MAX_LPC_ORDER + 1); i++) {
183    inst->dec_filtstate[i] = 0;
184    inst->dec_target_reflCoefs[i] = 0;
185    inst->dec_used_reflCoefs[i] = 0;
186  }
187  inst->dec_target_reflCoefs[0] = 0;
188  inst->dec_used_reflCoefs[0] = 0;
189  inst->dec_used_energy = 0;
190  inst->initflag = 1;
191
192  return 0;
193}
194
195/****************************************************************************
196 * WebRtcCng_FreeEnc/Dec(...)
197 *
198 * These functions frees the dynamic memory of a specified instance
199 *
200 * Input:
201 *    - cng_inst      : Pointer to created instance that should be freed
202 *
203 * Return value       :  0 - Ok
204 *                      -1 - Error
205 */
206int16_t WebRtcCng_FreeEnc(CNG_enc_inst* cng_inst) {
207  free(cng_inst);
208  return 0;
209}
210
211int16_t WebRtcCng_FreeDec(CNG_dec_inst* cng_inst) {
212  free(cng_inst);
213  return 0;
214}
215
216/****************************************************************************
217 * WebRtcCng_Encode(...)
218 *
219 * These functions analyzes background noise
220 *
221 * Input:
222 *    - cng_inst      : Pointer to created instance
223 *    - speech        : Signal (noise) to be analyzed
224 *    - nrOfSamples   : Size of speech vector
225 *    - bytesOut      : Nr of bytes to transmit, might be 0
226 *
227 * Return value       :  0 - Ok
228 *                      -1 - Error
229 */
230int16_t WebRtcCng_Encode(CNG_enc_inst* cng_inst, int16_t* speech,
231                         int16_t nrOfSamples, uint8_t* SIDdata,
232                         int16_t* bytesOut, int16_t forceSID) {
233  WebRtcCngEncInst_t* inst = (WebRtcCngEncInst_t*) cng_inst;
234
235  int16_t arCoefs[WEBRTC_CNG_MAX_LPC_ORDER + 1];
236  int32_t corrVector[WEBRTC_CNG_MAX_LPC_ORDER + 1];
237  int16_t refCs[WEBRTC_CNG_MAX_LPC_ORDER + 1];
238  int16_t hanningW[WEBRTC_CNG_MAX_OUTSIZE_ORDER];
239  int16_t ReflBeta = 19661;  /* 0.6 in q15. */
240  int16_t ReflBetaComp = 13107;  /* 0.4 in q15. */
241  int32_t outEnergy;
242  int outShifts;
243  int i, stab;
244  int acorrScale;
245  int index;
246  int16_t ind, factor;
247  int32_t* bptr;
248  int32_t blo, bhi;
249  int16_t negate;
250  const int16_t* aptr;
251  int16_t speechBuf[WEBRTC_CNG_MAX_OUTSIZE_ORDER];
252
253  /* Check if encoder initiated. */
254  if (inst->initflag != 1) {
255    inst->errorcode = CNG_ENCODER_NOT_INITIATED;
256    return -1;
257  }
258
259  /* Check framesize. */
260  if (nrOfSamples > WEBRTC_CNG_MAX_OUTSIZE_ORDER) {
261    inst->errorcode = CNG_DISALLOWED_FRAME_SIZE;
262    return -1;
263  }
264
265  for (i = 0; i < nrOfSamples; i++) {
266    speechBuf[i] = speech[i];
267  }
268
269  factor = nrOfSamples;
270
271  /* Calculate energy and a coefficients. */
272  outEnergy = WebRtcSpl_Energy(speechBuf, nrOfSamples, &outShifts);
273  while (outShifts > 0) {
274    /* We can only do 5 shifts without destroying accuracy in
275     * division factor. */
276    if (outShifts > 5) {
277      outEnergy <<= (outShifts - 5);
278      outShifts = 5;
279    } else {
280      factor /= 2;
281      outShifts--;
282    }
283  }
284  outEnergy = WebRtcSpl_DivW32W16(outEnergy, factor);
285
286  if (outEnergy > 1) {
287    /* Create Hanning Window. */
288    WebRtcSpl_GetHanningWindow(hanningW, nrOfSamples / 2);
289    for (i = 0; i < (nrOfSamples / 2); i++)
290      hanningW[nrOfSamples - i - 1] = hanningW[i];
291
292    WebRtcSpl_ElementwiseVectorMult(speechBuf, hanningW, speechBuf, nrOfSamples,
293                                    14);
294
295    WebRtcSpl_AutoCorrelation(speechBuf, nrOfSamples, inst->enc_nrOfCoefs,
296                              corrVector, &acorrScale);
297
298    if (*corrVector == 0)
299      *corrVector = WEBRTC_SPL_WORD16_MAX;
300
301    /* Adds the bandwidth expansion. */
302    aptr = WebRtcCng_kCorrWindow;
303    bptr = corrVector;
304
305    /* (zzz) lpc16_1 = 17+1+820+2+2 = 842 (ordo2=700). */
306    for (ind = 0; ind < inst->enc_nrOfCoefs; ind++) {
307      /* The below code multiplies the 16 b corrWindow values (Q15) with
308       * the 32 b corrvector (Q0) and shifts the result down 15 steps. */
309      negate = *bptr < 0;
310      if (negate)
311        *bptr = -*bptr;
312
313      blo = (int32_t) * aptr * (*bptr & 0xffff);
314      bhi = ((blo >> 16) & 0xffff)
315          + ((int32_t)(*aptr++) * ((*bptr >> 16) & 0xffff));
316      blo = (blo & 0xffff) | ((bhi & 0xffff) << 16);
317
318      *bptr = (((bhi >> 16) & 0x7fff) << 17) | ((uint32_t) blo >> 15);
319      if (negate)
320        *bptr = -*bptr;
321      bptr++;
322    }
323    /* End of bandwidth expansion. */
324
325    stab = WebRtcSpl_LevinsonDurbin(corrVector, arCoefs, refCs,
326                                    inst->enc_nrOfCoefs);
327
328    if (!stab) {
329      /* Disregard from this frame */
330      *bytesOut = 0;
331      return 0;
332    }
333
334  } else {
335    for (i = 0; i < inst->enc_nrOfCoefs; i++)
336      refCs[i] = 0;
337  }
338
339  if (forceSID) {
340    /* Read instantaneous values instead of averaged. */
341    for (i = 0; i < inst->enc_nrOfCoefs; i++)
342      inst->enc_reflCoefs[i] = refCs[i];
343    inst->enc_Energy = outEnergy;
344  } else {
345    /* Average history with new values. */
346    for (i = 0; i < (inst->enc_nrOfCoefs); i++) {
347      inst->enc_reflCoefs[i] = (int16_t) WEBRTC_SPL_MUL_16_16_RSFT(
348          inst->enc_reflCoefs[i], ReflBeta, 15);
349      inst->enc_reflCoefs[i] += (int16_t) WEBRTC_SPL_MUL_16_16_RSFT(
350          refCs[i], ReflBetaComp, 15);
351    }
352    inst->enc_Energy = (outEnergy >> 2) + (inst->enc_Energy >> 1)
353        + (inst->enc_Energy >> 2);
354  }
355
356  if (inst->enc_Energy < 1) {
357    inst->enc_Energy = 1;
358  }
359
360  if ((inst->enc_msSinceSID > (inst->enc_interval - 1)) || forceSID) {
361
362    /* Search for best dbov value. */
363    index = 0;
364    for (i = 1; i < 93; i++) {
365      /* Always round downwards. */
366      if ((inst->enc_Energy - WebRtcCng_kDbov[i]) > 0) {
367        index = i;
368        break;
369      }
370    }
371    if ((i == 93) && (index == 0))
372      index = 94;
373    SIDdata[0] = index;
374
375    /* Quantize coefficients with tweak for WebRtc implementation of RFC3389. */
376    if (inst->enc_nrOfCoefs == WEBRTC_CNG_MAX_LPC_ORDER) {
377      for (i = 0; i < inst->enc_nrOfCoefs; i++) {
378        /* Q15 to Q7 with rounding. */
379        SIDdata[i + 1] = ((inst->enc_reflCoefs[i] + 128) >> 8);
380      }
381    } else {
382      for (i = 0; i < inst->enc_nrOfCoefs; i++) {
383        /* Q15 to Q7 with rounding. */
384        SIDdata[i + 1] = (127 + ((inst->enc_reflCoefs[i] + 128) >> 8));
385      }
386    }
387
388    inst->enc_msSinceSID = 0;
389    *bytesOut = inst->enc_nrOfCoefs + 1;
390
391    inst->enc_msSinceSID += (1000 * nrOfSamples) / inst->enc_sampfreq;
392    return inst->enc_nrOfCoefs + 1;
393  } else {
394    inst->enc_msSinceSID += (1000 * nrOfSamples) / inst->enc_sampfreq;
395    *bytesOut = 0;
396    return 0;
397  }
398}
399
400/****************************************************************************
401 * WebRtcCng_UpdateSid(...)
402 *
403 * These functions updates the CN state, when a new SID packet arrives
404 *
405 * Input:
406 *    - cng_inst      : Pointer to created instance that should be freed
407 *    - SID           : SID packet, all headers removed
408 *    - length        : Length in bytes of SID packet
409 *
410 * Return value       :  0 - Ok
411 *                      -1 - Error
412 */
413int16_t WebRtcCng_UpdateSid(CNG_dec_inst* cng_inst, uint8_t* SID,
414                            int16_t length) {
415
416  WebRtcCngDecInst_t* inst = (WebRtcCngDecInst_t*) cng_inst;
417  int16_t refCs[WEBRTC_CNG_MAX_LPC_ORDER];
418  int32_t targetEnergy;
419  int i;
420
421  if (inst->initflag != 1) {
422    inst->errorcode = CNG_DECODER_NOT_INITIATED;
423    return -1;
424  }
425
426  /* Throw away reflection coefficients of higher order than we can handle. */
427  if (length > (WEBRTC_CNG_MAX_LPC_ORDER + 1))
428    length = WEBRTC_CNG_MAX_LPC_ORDER + 1;
429
430  inst->dec_order = length - 1;
431
432  if (SID[0] > 93)
433    SID[0] = 93;
434  targetEnergy = WebRtcCng_kDbov[SID[0]];
435  /* Take down target energy to 75%. */
436  targetEnergy = targetEnergy >> 1;
437  targetEnergy += targetEnergy >> 2;
438
439  inst->dec_target_energy = targetEnergy;
440
441  /* Reconstruct coeffs with tweak for WebRtc implementation of RFC3389. */
442  if (inst->dec_order == WEBRTC_CNG_MAX_LPC_ORDER) {
443    for (i = 0; i < (inst->dec_order); i++) {
444      refCs[i] = SID[i + 1] << 8; /* Q7 to Q15*/
445      inst->dec_target_reflCoefs[i] = refCs[i];
446    }
447  } else {
448    for (i = 0; i < (inst->dec_order); i++) {
449      refCs[i] = (SID[i + 1] - 127) << 8; /* Q7 to Q15. */
450      inst->dec_target_reflCoefs[i] = refCs[i];
451    }
452  }
453
454  for (i = (inst->dec_order); i < WEBRTC_CNG_MAX_LPC_ORDER; i++) {
455    refCs[i] = 0;
456    inst->dec_target_reflCoefs[i] = refCs[i];
457  }
458
459  return 0;
460}
461
462/****************************************************************************
463 * WebRtcCng_Generate(...)
464 *
465 * These functions generates CN data when needed
466 *
467 * Input:
468 *    - cng_inst      : Pointer to created instance that should be freed
469 *    - outData       : pointer to area to write CN data
470 *    - nrOfSamples   : How much data to generate
471 *
472 * Return value        :  0 - Ok
473 *                       -1 - Error
474 */
475int16_t WebRtcCng_Generate(CNG_dec_inst* cng_inst, int16_t* outData,
476                           int16_t nrOfSamples, int16_t new_period) {
477  WebRtcCngDecInst_t* inst = (WebRtcCngDecInst_t*) cng_inst;
478
479  int i;
480  int16_t excitation[WEBRTC_CNG_MAX_OUTSIZE_ORDER];
481  int16_t low[WEBRTC_CNG_MAX_OUTSIZE_ORDER];
482  int16_t lpPoly[WEBRTC_CNG_MAX_LPC_ORDER + 1];
483  int16_t ReflBetaStd = 26214;  /* 0.8 in q15. */
484  int16_t ReflBetaCompStd = 6553;  /* 0.2 in q15. */
485  int16_t ReflBetaNewP = 19661;  /* 0.6 in q15. */
486  int16_t ReflBetaCompNewP = 13107;  /* 0.4 in q15. */
487  int16_t Beta, BetaC, tmp1, tmp2, tmp3;
488  int32_t targetEnergy;
489  int16_t En;
490  int16_t temp16;
491
492  if (nrOfSamples > WEBRTC_CNG_MAX_OUTSIZE_ORDER) {
493    inst->errorcode = CNG_DISALLOWED_FRAME_SIZE;
494    return -1;
495  }
496
497  if (new_period) {
498    inst->dec_used_scale_factor = inst->dec_target_scale_factor;
499    Beta = ReflBetaNewP;
500    BetaC = ReflBetaCompNewP;
501  } else {
502    Beta = ReflBetaStd;
503    BetaC = ReflBetaCompStd;
504  }
505
506  /* Here we use a 0.5 weighting, should possibly be modified to 0.6. */
507  tmp1 = inst->dec_used_scale_factor << 2; /* Q13->Q15 */
508  tmp2 = inst->dec_target_scale_factor << 2; /* Q13->Q15 */
509  tmp3 = (int16_t) WEBRTC_SPL_MUL_16_16_RSFT(tmp1, Beta, 15);
510  tmp3 += (int16_t) WEBRTC_SPL_MUL_16_16_RSFT(tmp2, BetaC, 15);
511  inst->dec_used_scale_factor = tmp3 >> 2; /* Q15->Q13 */
512
513  inst->dec_used_energy = inst->dec_used_energy >> 1;
514  inst->dec_used_energy += inst->dec_target_energy >> 1;
515
516  /* Do the same for the reflection coeffs. */
517  for (i = 0; i < WEBRTC_CNG_MAX_LPC_ORDER; i++) {
518    inst->dec_used_reflCoefs[i] = (int16_t) WEBRTC_SPL_MUL_16_16_RSFT(
519        inst->dec_used_reflCoefs[i], Beta, 15);
520    inst->dec_used_reflCoefs[i] += (int16_t) WEBRTC_SPL_MUL_16_16_RSFT(
521        inst->dec_target_reflCoefs[i], BetaC, 15);
522  }
523
524  /* Compute the polynomial coefficients. */
525  WebRtcCng_K2a16(inst->dec_used_reflCoefs, WEBRTC_CNG_MAX_LPC_ORDER, lpPoly);
526
527
528  targetEnergy = inst->dec_used_energy;
529
530  /* Calculate scaling factor based on filter energy. */
531  En = 8192;  /* 1.0 in Q13. */
532  for (i = 0; i < (WEBRTC_CNG_MAX_LPC_ORDER); i++) {
533
534    /* Floating point value for reference.
535       E *= 1.0 - (inst->dec_used_reflCoefs[i] / 32768.0) *
536       (inst->dec_used_reflCoefs[i] / 32768.0);
537     */
538
539    /* Same in fixed point. */
540    /* K(i).^2 in Q15. */
541    temp16 = (int16_t) WEBRTC_SPL_MUL_16_16_RSFT(
542        inst->dec_used_reflCoefs[i], inst->dec_used_reflCoefs[i], 15);
543    /* 1 - K(i).^2 in Q15. */
544    temp16 = 0x7fff - temp16;
545    En = (int16_t) WEBRTC_SPL_MUL_16_16_RSFT(En, temp16, 15);
546  }
547
548  /* float scaling= sqrt(E * inst->dec_target_energy / (1 << 24)); */
549
550  /* Calculate sqrt(En * target_energy / excitation energy) */
551  targetEnergy = WebRtcSpl_Sqrt(inst->dec_used_energy);
552
553  En = (int16_t) WebRtcSpl_Sqrt(En) << 6;
554  En = (En * 3) >> 1;  /* 1.5 estimates sqrt(2). */
555  inst->dec_used_scale_factor = (int16_t)((En * targetEnergy) >> 12);
556
557  /* Generate excitation. */
558  /* Excitation energy per sample is 2.^24 - Q13 N(0,1). */
559  for (i = 0; i < nrOfSamples; i++) {
560    excitation[i] = WebRtcSpl_RandN(&inst->dec_seed) >> 1;
561  }
562
563  /* Scale to correct energy. */
564  WebRtcSpl_ScaleVector(excitation, excitation, inst->dec_used_scale_factor,
565                        nrOfSamples, 13);
566
567  /* |lpPoly| - Coefficients in Q12.
568   * |excitation| - Speech samples.
569   * |nst->dec_filtstate| - State preservation.
570   * |outData| - Filtered speech samples. */
571  WebRtcSpl_FilterAR(lpPoly, WEBRTC_CNG_MAX_LPC_ORDER + 1, excitation,
572                     nrOfSamples, inst->dec_filtstate, WEBRTC_CNG_MAX_LPC_ORDER,
573                     inst->dec_filtstateLow, WEBRTC_CNG_MAX_LPC_ORDER, outData,
574                     low, nrOfSamples);
575
576  return 0;
577}
578
579/****************************************************************************
580 * WebRtcCng_GetErrorCodeEnc/Dec(...)
581 *
582 * This functions can be used to check the error code of a CNG instance. When
583 * a function returns -1 a error code will be set for that instance. The
584 * function below extract the code of the last error that occured in the
585 * specified instance.
586 *
587 * Input:
588 *    - CNG_inst    : CNG enc/dec instance
589 *
590 * Return value     : Error code
591 */
592int16_t WebRtcCng_GetErrorCodeEnc(CNG_enc_inst* cng_inst) {
593  /* Typecast pointer to real structure. */
594  WebRtcCngEncInst_t* inst = (WebRtcCngEncInst_t*) cng_inst;
595  return inst->errorcode;
596}
597
598int16_t WebRtcCng_GetErrorCodeDec(CNG_dec_inst* cng_inst) {
599  /* Typecast pointer to real structure. */
600  WebRtcCngDecInst_t* inst = (WebRtcCngDecInst_t*) cng_inst;
601  return inst->errorcode;
602}
603