/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include <stdlib.h>
//#include <string.h>
#include "echo_control_mobile.h"
#include "aecm_core.h"
#include "ring_buffer.h"
#ifdef AEC_DEBUG
#include <stdio.h>
#endif
#ifdef MAC_IPHONE_PRINT
#include <time.h>
#include <stdio.h>
#elif defined ARM_WINM_LOG
#include "windows.h"
extern HANDLE logFile;
#endif
#define BUF_SIZE_FRAMES 50 // buffer size (frames)
// Maximum length of resampled signal. Must be an integer multiple of frames
// (ceil(1/(1 + MIN_SKEW)*2) + 1)*FRAME_LEN
// The factor of 2 handles wb, and the + 1 is as a safety margin
#define MAX_RESAMP_LEN (5 * FRAME_LEN)
static const size_t kBufSizeSamp = BUF_SIZE_FRAMES * FRAME_LEN; // buffer size (samples)
static const int kSampMsNb = 8; // samples per ms in nb
// Target suppression levels for nlp modes
// log{0.001, 0.00001, 0.00000001}
static const int kInitCheck = 42;
typedef struct
{
int sampFreq;
int scSampFreq;
short bufSizeStart;
int knownDelay;
// Stores the last frame added to the farend buffer
short farendOld[2][FRAME_LEN];
short initFlag; // indicates if AEC has been initialized
// Variables used for averaging far end buffer size
short counter;
short sum;
short firstVal;
short checkBufSizeCtr;
// Variables used for delay shifts
short msInSndCardBuf;
short filtDelay;
int timeForDelayChange;
int ECstartup;
int checkBuffSize;
int delayChange;
short lastDelayDiff;
WebRtc_Word16 echoMode;
#ifdef AEC_DEBUG
FILE *bufFile;
FILE *delayFile;
FILE *preCompFile;
FILE *postCompFile;
#endif // AEC_DEBUG
// Structures
void *farendBuf;
int lastError;
AecmCore_t *aecmCore;
} aecmob_t;
// Estimates delay to set the position of the farend buffer read pointer
// (controlled by knownDelay)
static int WebRtcAecm_EstBufDelay(aecmob_t *aecmInst, short msInSndCardBuf);
// Stuffs the farend buffer if the estimated delay is too large
static int WebRtcAecm_DelayComp(aecmob_t *aecmInst);
WebRtc_Word32 WebRtcAecm_Create(void **aecmInst)
{
aecmob_t *aecm;
if (aecmInst == NULL)
{
return -1;
}
aecm = malloc(sizeof(aecmob_t));
*aecmInst = aecm;
if (aecm == NULL)
{
return -1;
}
if (WebRtcAecm_CreateCore(&aecm->aecmCore) == -1)
{
WebRtcAecm_Free(aecm);
aecm = NULL;
return -1;
}
if (WebRtc_CreateBuffer(&aecm->farendBuf, kBufSizeSamp,
sizeof(int16_t)) == -1)
{
WebRtcAecm_Free(aecm);
aecm = NULL;
return -1;
}
aecm->initFlag = 0;
aecm->lastError = 0;
#ifdef AEC_DEBUG
aecm->aecmCore->farFile = fopen("aecFar.pcm","wb");
aecm->aecmCore->nearFile = fopen("aecNear.pcm","wb");
aecm->aecmCore->outFile = fopen("aecOut.pcm","wb");
//aecm->aecmCore->outLpFile = fopen("aecOutLp.pcm","wb");
aecm->bufFile = fopen("aecBuf.dat", "wb");
aecm->delayFile = fopen("aecDelay.dat", "wb");
aecm->preCompFile = fopen("preComp.pcm", "wb");
aecm->postCompFile = fopen("postComp.pcm", "wb");
#endif // AEC_DEBUG
return 0;
}
WebRtc_Word32 WebRtcAecm_Free(void *aecmInst)
{
aecmob_t *aecm = aecmInst;
if (aecm == NULL)
{
return -1;
}
#ifdef AEC_DEBUG
fclose(aecm->aecmCore->farFile);
fclose(aecm->aecmCore->nearFile);
fclose(aecm->aecmCore->outFile);
//fclose(aecm->aecmCore->outLpFile);
fclose(aecm->bufFile);
fclose(aecm->delayFile);
fclose(aecm->preCompFile);
fclose(aecm->postCompFile);
#endif // AEC_DEBUG
WebRtcAecm_FreeCore(aecm->aecmCore);
WebRtc_FreeBuffer(aecm->farendBuf);
free(aecm);
return 0;
}
WebRtc_Word32 WebRtcAecm_Init(void *aecmInst, WebRtc_Word32 sampFreq)
{
aecmob_t *aecm = aecmInst;
AecmConfig aecConfig;
if (aecm == NULL)
{
return -1;
}
if (sampFreq != 8000 && sampFreq != 16000)
{
aecm->lastError = AECM_BAD_PARAMETER_ERROR;
return -1;
}
aecm->sampFreq = sampFreq;
// Initialize AECM core
if (WebRtcAecm_InitCore(aecm->aecmCore, aecm->sampFreq) == -1)
{
aecm->lastError = AECM_UNSPECIFIED_ERROR;
return -1;
}
// Initialize farend buffer
if (WebRtc_InitBuffer(aecm->farendBuf) == -1)
{
aecm->lastError = AECM_UNSPECIFIED_ERROR;
return -1;
}
aecm->initFlag = kInitCheck; // indicates that initialization has been done
aecm->delayChange = 1;
aecm->sum = 0;
aecm->counter = 0;
aecm->checkBuffSize = 1;
aecm->firstVal = 0;
aecm->ECstartup = 1;
aecm->bufSizeStart = 0;
aecm->checkBufSizeCtr = 0;
aecm->filtDelay = 0;
aecm->timeForDelayChange = 0;
aecm->knownDelay = 0;
aecm->lastDelayDiff = 0;
memset(&aecm->farendOld[0][0], 0, 160);
// Default settings.
aecConfig.cngMode = AecmTrue;
aecConfig.echoMode = 3;
if (WebRtcAecm_set_config(aecm, aecConfig) == -1)
{
aecm->lastError = AECM_UNSPECIFIED_ERROR;
return -1;
}
return 0;
}
WebRtc_Word32 WebRtcAecm_BufferFarend(void *aecmInst, const WebRtc_Word16 *farend,
WebRtc_Word16 nrOfSamples)
{
aecmob_t *aecm = aecmInst;
WebRtc_Word32 retVal = 0;
if (aecm == NULL)
{
return -1;
}
if (farend == NULL)
{
aecm->lastError = AECM_NULL_POINTER_ERROR;
return -1;
}
if (aecm->initFlag != kInitCheck)
{
aecm->lastError = AECM_UNINITIALIZED_ERROR;
return -1;
}
if (nrOfSamples != 80 && nrOfSamples != 160)
{
aecm->lastError = AECM_BAD_PARAMETER_ERROR;
return -1;
}
// TODO: Is this really a good idea?
if (!aecm->ECstartup)
{
WebRtcAecm_DelayComp(aecm);
}
WebRtc_WriteBuffer(aecm->farendBuf, farend, (size_t) nrOfSamples);
return retVal;
}
WebRtc_Word32 WebRtcAecm_Process(void *aecmInst, const WebRtc_Word16 *nearendNoisy,
const WebRtc_Word16 *nearendClean, WebRtc_Word16 *out,
WebRtc_Word16 nrOfSamples, WebRtc_Word16 msInSndCardBuf)
{
aecmob_t *aecm = aecmInst;
WebRtc_Word32 retVal = 0;
short i;
short nmbrOfFilledBuffers;
short nBlocks10ms;
short nFrames;
#ifdef AEC_DEBUG
short msInAECBuf;
#endif
#ifdef ARM_WINM_LOG
__int64 freq, start, end, diff;
unsigned int milliseconds;
DWORD temp;
#elif defined MAC_IPHONE_PRINT
// double endtime = 0, starttime = 0;
struct timeval starttime;
struct timeval endtime;
static long int timeused = 0;
static int timecount = 0;
#endif
if (aecm == NULL)
{
return -1;
}
if (nearendNoisy == NULL)
{
aecm->lastError = AECM_NULL_POINTER_ERROR;
return -1;
}
if (out == NULL)
{
aecm->lastError = AECM_NULL_POINTER_ERROR;
return -1;
}
if (aecm->initFlag != kInitCheck)
{
aecm->lastError = AECM_UNINITIALIZED_ERROR;
return -1;
}
if (nrOfSamples != 80 && nrOfSamples != 160)
{
aecm->lastError = AECM_BAD_PARAMETER_ERROR;
return -1;
}
if (msInSndCardBuf < 0)
{
msInSndCardBuf = 0;
aecm->lastError = AECM_BAD_PARAMETER_WARNING;
retVal = -1;
} else if (msInSndCardBuf > 500)
{
msInSndCardBuf = 500;
aecm->lastError = AECM_BAD_PARAMETER_WARNING;
retVal = -1;
}
msInSndCardBuf += 10;
aecm->msInSndCardBuf = msInSndCardBuf;
nFrames = nrOfSamples / FRAME_LEN;
nBlocks10ms = nFrames / aecm->aecmCore->mult;
if (aecm->ECstartup)
{
if (nearendClean == NULL)
{
memcpy(out, nearendNoisy, sizeof(short) * nrOfSamples);
} else
{
memcpy(out, nearendClean, sizeof(short) * nrOfSamples);
}
nmbrOfFilledBuffers =
(short) WebRtc_available_read(aecm->farendBuf) / FRAME_LEN;
// The AECM is in the start up mode
// AECM is disabled until the soundcard buffer and farend buffers are OK
// Mechanism to ensure that the soundcard buffer is reasonably stable.
if (aecm->checkBuffSize)
{
aecm->checkBufSizeCtr++;
// Before we fill up the far end buffer we require the amount of data on the
// sound card to be stable (+/-8 ms) compared to the first value. This
// comparison is made during the following 4 consecutive frames. If it seems
// to be stable then we start to fill up the far end buffer.
if (aecm->counter == 0)
{
aecm->firstVal = aecm->msInSndCardBuf;
aecm->sum = 0;
}
if (abs(aecm->firstVal - aecm->msInSndCardBuf)
< WEBRTC_SPL_MAX(0.2 * aecm->msInSndCardBuf, kSampMsNb))
{
aecm->sum += aecm->msInSndCardBuf;
aecm->counter++;
} else
{
aecm->counter = 0;
}
if (aecm->counter * nBlocks10ms >= 6)
{
// The farend buffer size is determined in blocks of 80 samples
// Use 75% of the average value of the soundcard buffer
aecm->bufSizeStart
= WEBRTC_SPL_MIN((3 * aecm->sum
* aecm->aecmCore->mult) / (aecm->counter * 40), BUF_SIZE_FRAMES);
// buffersize has now been determined
aecm->checkBuffSize = 0;
}
if (aecm->checkBufSizeCtr * nBlocks10ms > 50)
{
// for really bad sound cards, don't disable echocanceller for more than 0.5 sec
aecm->bufSizeStart = WEBRTC_SPL_MIN((3 * aecm->msInSndCardBuf
* aecm->aecmCore->mult) / 40, BUF_SIZE_FRAMES);
aecm->checkBuffSize = 0;
}
}
// if checkBuffSize changed in the if-statement above
if (!aecm->checkBuffSize)
{
// soundcard buffer is now reasonably stable
// When the far end buffer is filled with approximately the same amount of
// data as the amount on the sound card we end the start up phase and start
// to cancel echoes.
if (nmbrOfFilledBuffers == aecm->bufSizeStart)
{
aecm->ECstartup = 0; // Enable the AECM
} else if (nmbrOfFilledBuffers > aecm->bufSizeStart)
{
WebRtc_MoveReadPtr(aecm->farendBuf,
(int) WebRtc_available_read(aecm->farendBuf)
- (int) aecm->bufSizeStart * FRAME_LEN);
aecm->ECstartup = 0;
}
}
} else
{
// AECM is enabled
// Note only 1 block supported for nb and 2 blocks for wb
for (i = 0; i < nFrames; i++)
{
int16_t farend[FRAME_LEN];
const int16_t* farend_ptr = NULL;
nmbrOfFilledBuffers =
(short) WebRtc_available_read(aecm->farendBuf) / FRAME_LEN;
// Check that there is data in the far end buffer
if (nmbrOfFilledBuffers > 0)
{
// Get the next 80 samples from the farend buffer
WebRtc_ReadBuffer(aecm->farendBuf, (void**) &farend_ptr, farend,
FRAME_LEN);
// Always store the last frame for use when we run out of data
memcpy(&(aecm->farendOld[i][0]), farend_ptr,
FRAME_LEN * sizeof(short));
} else
{
// We have no data so we use the last played frame
memcpy(farend, &(aecm->farendOld[i][0]), FRAME_LEN * sizeof(short));
farend_ptr = farend;
}
// Call buffer delay estimator when all data is extracted,
// i,e. i = 0 for NB and i = 1 for WB
if ((i == 0 && aecm->sampFreq == 8000) || (i == 1 && aecm->sampFreq == 16000))
{
WebRtcAecm_EstBufDelay(aecm, aecm->msInSndCardBuf);
}
#ifdef ARM_WINM_LOG
// measure tick start
QueryPerformanceFrequency((LARGE_INTEGER*)&freq);
QueryPerformanceCounter((LARGE_INTEGER*)&start);
#elif defined MAC_IPHONE_PRINT
// starttime = clock()/(double)CLOCKS_PER_SEC;
gettimeofday(&starttime, NULL);
#endif
// Call the AECM
/*WebRtcAecm_ProcessFrame(aecm->aecmCore, farend, &nearend[FRAME_LEN * i],
&out[FRAME_LEN * i], aecm->knownDelay);*/
if (nearendClean == NULL)
{
if (WebRtcAecm_ProcessFrame(aecm->aecmCore,
farend_ptr,
&nearendNoisy[FRAME_LEN * i],
NULL,
&out[FRAME_LEN * i]) == -1)
{
return -1;
}
} else
{
if (WebRtcAecm_ProcessFrame(aecm->aecmCore,
farend_ptr,
&nearendNoisy[FRAME_LEN * i],
&nearendClean[FRAME_LEN * i],
&out[FRAME_LEN * i]) == -1)
{
return -1;
}
}
#ifdef ARM_WINM_LOG
// measure tick end
QueryPerformanceCounter((LARGE_INTEGER*)&end);
if(end > start)
{
diff = ((end - start) * 1000) / (freq/1000);
milliseconds = (unsigned int)(diff & 0xffffffff);
WriteFile (logFile, &milliseconds, sizeof(unsigned int), &temp, NULL);
}
#elif defined MAC_IPHONE_PRINT
// endtime = clock()/(double)CLOCKS_PER_SEC;
// printf("%f\n", endtime - starttime);
gettimeofday(&endtime, NULL);
if( endtime.tv_usec > starttime.tv_usec)
{
timeused += endtime.tv_usec - starttime.tv_usec;
} else
{
timeused += endtime.tv_usec + 1000000 - starttime.tv_usec;
}
if(++timecount == 1000)
{
timecount = 0;
printf("AEC: %ld\n", timeused);
timeused = 0;
}
#endif
}
}
#ifdef AEC_DEBUG
msInAECBuf = (short) WebRtc_available_read(aecm->farendBuf) /
(kSampMsNb * aecm->aecmCore->mult);
fwrite(&msInAECBuf, 2, 1, aecm->bufFile);
fwrite(&(aecm->knownDelay), sizeof(aecm->knownDelay), 1, aecm->delayFile);
#endif
return retVal;
}
WebRtc_Word32 WebRtcAecm_set_config(void *aecmInst, AecmConfig config)
{
aecmob_t *aecm = aecmInst;
if (aecm == NULL)
{
return -1;
}
if (aecm->initFlag != kInitCheck)
{
aecm->lastError = AECM_UNINITIALIZED_ERROR;
return -1;
}
if (config.cngMode != AecmFalse && config.cngMode != AecmTrue)
{
aecm->lastError = AECM_BAD_PARAMETER_ERROR;
return -1;
}
aecm->aecmCore->cngMode = config.cngMode;
if (config.echoMode < 0 || config.echoMode > 4)
{
aecm->lastError = AECM_BAD_PARAMETER_ERROR;
return -1;
}
aecm->echoMode = config.echoMode;
if (aecm->echoMode == 0)
{
aecm->aecmCore->supGain = SUPGAIN_DEFAULT >> 3;
aecm->aecmCore->supGainOld = SUPGAIN_DEFAULT >> 3;
aecm->aecmCore->supGainErrParamA = SUPGAIN_ERROR_PARAM_A >> 3;
aecm->aecmCore->supGainErrParamD = SUPGAIN_ERROR_PARAM_D >> 3;
aecm->aecmCore->supGainErrParamDiffAB = (SUPGAIN_ERROR_PARAM_A >> 3)
- (SUPGAIN_ERROR_PARAM_B >> 3);
aecm->aecmCore->supGainErrParamDiffBD = (SUPGAIN_ERROR_PARAM_B >> 3)
- (SUPGAIN_ERROR_PARAM_D >> 3);
} else if (aecm->echoMode == 1)
{
aecm->aecmCore->supGain = SUPGAIN_DEFAULT >> 2;
aecm->aecmCore->supGainOld = SUPGAIN_DEFAULT >> 2;
aecm->aecmCore->supGainErrParamA = SUPGAIN_ERROR_PARAM_A >> 2;
aecm->aecmCore->supGainErrParamD = SUPGAIN_ERROR_PARAM_D >> 2;
aecm->aecmCore->supGainErrParamDiffAB = (SUPGAIN_ERROR_PARAM_A >> 2)
- (SUPGAIN_ERROR_PARAM_B >> 2);
aecm->aecmCore->supGainErrParamDiffBD = (SUPGAIN_ERROR_PARAM_B >> 2)
- (SUPGAIN_ERROR_PARAM_D >> 2);
} else if (aecm->echoMode == 2)
{
aecm->aecmCore->supGain = SUPGAIN_DEFAULT >> 1;
aecm->aecmCore->supGainOld = SUPGAIN_DEFAULT >> 1;
aecm->aecmCore->supGainErrParamA = SUPGAIN_ERROR_PARAM_A >> 1;
aecm->aecmCore->supGainErrParamD = SUPGAIN_ERROR_PARAM_D >> 1;
aecm->aecmCore->supGainErrParamDiffAB = (SUPGAIN_ERROR_PARAM_A >> 1)
- (SUPGAIN_ERROR_PARAM_B >> 1);
aecm->aecmCore->supGainErrParamDiffBD = (SUPGAIN_ERROR_PARAM_B >> 1)
- (SUPGAIN_ERROR_PARAM_D >> 1);
} else if (aecm->echoMode == 3)
{
aecm->aecmCore->supGain = SUPGAIN_DEFAULT;
aecm->aecmCore->supGainOld = SUPGAIN_DEFAULT;
aecm->aecmCore->supGainErrParamA = SUPGAIN_ERROR_PARAM_A;
aecm->aecmCore->supGainErrParamD = SUPGAIN_ERROR_PARAM_D;
aecm->aecmCore->supGainErrParamDiffAB = SUPGAIN_ERROR_PARAM_A - SUPGAIN_ERROR_PARAM_B;
aecm->aecmCore->supGainErrParamDiffBD = SUPGAIN_ERROR_PARAM_B - SUPGAIN_ERROR_PARAM_D;
} else if (aecm->echoMode == 4)
{
aecm->aecmCore->supGain = SUPGAIN_DEFAULT << 1;
aecm->aecmCore->supGainOld = SUPGAIN_DEFAULT << 1;
aecm->aecmCore->supGainErrParamA = SUPGAIN_ERROR_PARAM_A << 1;
aecm->aecmCore->supGainErrParamD = SUPGAIN_ERROR_PARAM_D << 1;
aecm->aecmCore->supGainErrParamDiffAB = (SUPGAIN_ERROR_PARAM_A << 1)
- (SUPGAIN_ERROR_PARAM_B << 1);
aecm->aecmCore->supGainErrParamDiffBD = (SUPGAIN_ERROR_PARAM_B << 1)
- (SUPGAIN_ERROR_PARAM_D << 1);
}
return 0;
}
WebRtc_Word32 WebRtcAecm_get_config(void *aecmInst, AecmConfig *config)
{
aecmob_t *aecm = aecmInst;
if (aecm == NULL)
{
return -1;
}
if (config == NULL)
{
aecm->lastError = AECM_NULL_POINTER_ERROR;
return -1;
}
if (aecm->initFlag != kInitCheck)
{
aecm->lastError = AECM_UNINITIALIZED_ERROR;
return -1;
}
config->cngMode = aecm->aecmCore->cngMode;
config->echoMode = aecm->echoMode;
return 0;
}
WebRtc_Word32 WebRtcAecm_InitEchoPath(void* aecmInst,
const void* echo_path,
size_t size_bytes)
{
aecmob_t *aecm = aecmInst;
const WebRtc_Word16* echo_path_ptr = echo_path;
if ((aecm == NULL) || (echo_path == NULL))
{
aecm->lastError = AECM_NULL_POINTER_ERROR;
return -1;
}
if (size_bytes != WebRtcAecm_echo_path_size_bytes())
{
// Input channel size does not match the size of AECM
aecm->lastError = AECM_BAD_PARAMETER_ERROR;
return -1;
}
if (aecm->initFlag != kInitCheck)
{
aecm->lastError = AECM_UNINITIALIZED_ERROR;
return -1;
}
WebRtcAecm_InitEchoPathCore(aecm->aecmCore, echo_path_ptr);
return 0;
}
WebRtc_Word32 WebRtcAecm_GetEchoPath(void* aecmInst,
void* echo_path,
size_t size_bytes)
{
aecmob_t *aecm = aecmInst;
WebRtc_Word16* echo_path_ptr = echo_path;
if ((aecm == NULL) || (echo_path == NULL))
{
aecm->lastError = AECM_NULL_POINTER_ERROR;
return -1;
}
if (size_bytes != WebRtcAecm_echo_path_size_bytes())
{
// Input channel size does not match the size of AECM
aecm->lastError = AECM_BAD_PARAMETER_ERROR;
return -1;
}
if (aecm->initFlag != kInitCheck)
{
aecm->lastError = AECM_UNINITIALIZED_ERROR;
return -1;
}
memcpy(echo_path_ptr, aecm->aecmCore->channelStored, size_bytes);
return 0;
}
size_t WebRtcAecm_echo_path_size_bytes()
{
return (PART_LEN1 * sizeof(WebRtc_Word16));
}
WebRtc_Word32 WebRtcAecm_get_version(WebRtc_Word8 *versionStr, WebRtc_Word16 len)
{
const char version[] = "AECM 1.2.0";
const short versionLen = (short)strlen(version) + 1; // +1 for null-termination
if (versionStr == NULL)
{
return -1;
}
if (versionLen > len)
{
return -1;
}
strncpy(versionStr, version, versionLen);
return 0;
}
WebRtc_Word32 WebRtcAecm_get_error_code(void *aecmInst)
{
aecmob_t *aecm = aecmInst;
if (aecm == NULL)
{
return -1;
}
return aecm->lastError;
}
static int WebRtcAecm_EstBufDelay(aecmob_t *aecm, short msInSndCardBuf)
{
short delayNew, nSampSndCard;
short nSampFar = (short) WebRtc_available_read(aecm->farendBuf);
short diff;
nSampSndCard = msInSndCardBuf * kSampMsNb * aecm->aecmCore->mult;
delayNew = nSampSndCard - nSampFar;
if (delayNew < FRAME_LEN)
{
WebRtc_MoveReadPtr(aecm->farendBuf, FRAME_LEN);
delayNew += FRAME_LEN;
}
aecm->filtDelay = WEBRTC_SPL_MAX(0, (8 * aecm->filtDelay + 2 * delayNew) / 10);
diff = aecm->filtDelay - aecm->knownDelay;
if (diff > 224)
{
if (aecm->lastDelayDiff < 96)
{
aecm->timeForDelayChange = 0;
} else
{
aecm->timeForDelayChange++;
}
} else if (diff < 96 && aecm->knownDelay > 0)
{
if (aecm->lastDelayDiff > 224)
{
aecm->timeForDelayChange = 0;
} else
{
aecm->timeForDelayChange++;
}
} else
{
aecm->timeForDelayChange = 0;
}
aecm->lastDelayDiff = diff;
if (aecm->timeForDelayChange > 25)
{
aecm->knownDelay = WEBRTC_SPL_MAX((int)aecm->filtDelay - 160, 0);
}
return 0;
}
static int WebRtcAecm_DelayComp(aecmob_t *aecm)
{
int nSampFar = (int) WebRtc_available_read(aecm->farendBuf);
int nSampSndCard, delayNew, nSampAdd;
const int maxStuffSamp = 10 * FRAME_LEN;
nSampSndCard = aecm->msInSndCardBuf * kSampMsNb * aecm->aecmCore->mult;
delayNew = nSampSndCard - nSampFar;
if (delayNew > FAR_BUF_LEN - FRAME_LEN * aecm->aecmCore->mult)
{
// The difference of the buffer sizes is larger than the maximum
// allowed known delay. Compensate by stuffing the buffer.
nSampAdd = (int)(WEBRTC_SPL_MAX(((nSampSndCard >> 1) - nSampFar),
FRAME_LEN));
nSampAdd = WEBRTC_SPL_MIN(nSampAdd, maxStuffSamp);
WebRtc_MoveReadPtr(aecm->farendBuf, -nSampAdd);
aecm->delayChange = 1; // the delay needs to be updated
}
return 0;
}