protected override void PerformEchoCancellation(short[] recorded, short[] played, short[] outFrame)
{
// ks 11/2/11 - This seems to be more-or-less the order in which things are processed in the WebRtc audio_processing_impl.cc file.
_highPassFilter.Filter(recorded);
if (_enableAgc)
{
_agc.WebRtcAgc_AddFarend(played, (short)played.Length);
gain_control_AnalyzeCaptureAudio(recorded);
}
if (_enableAec)
{
_aec.ProcessFrame(recorded, played, outFrame, 0);
}
else
{
Buffer.BlockCopy(recorded, 0, outFrame, 0, SamplesPerFrame * sizeof(short));
}
if (_enableDenoise)
{
// ks 11/14/11 - The noise suppressor only supports 10 ms blocks. I might be able to fix that,
// but this is easier for now.
_ns.ProcessFrame(outFrame, 0, outFrame, 0);
_ns.ProcessFrame(outFrame, _recordedAudioFormat.SamplesPer10Ms, outFrame, _recordedAudioFormat.SamplesPer10Ms);
}
if (_enableAgc)
{
gain_control_ProcessCaptureAudio(outFrame);
}
}
public void WebRtcAec_Process(short[] nearend, short streamDelayMs, int skew)
{
int nrOfSamples = nearend.Length;
short msInSndCardBuf = streamDelayMs;
var farend = new short[aecConfig.SamplesPerFrame];
short nmbrOfFilledBuffers;
// number of samples == 160 for SWB input
if (nrOfSamples != 80 && nrOfSamples != 160)
{
throw new ArgumentException();
}
// Check for valid pointers based on sampling rate
if (sampFreq == 32000)
{
throw new ArgumentException();
}
if (msInSndCardBuf < 0)
{
msInSndCardBuf = 0;
//throw new ArgumentException();//todo:warning
}
else if (msInSndCardBuf > 500)
{
msInSndCardBuf = 500;
//todo:warning
}
msInSndCardBuf += 10;
this.msInSndCardBuf = msInSndCardBuf;
if (skewMode)
{
//if (aecpc->skewFrCtr < 25) {
// aecpc->skewFrCtr++;
//}
//else {
// retVal = WebRtcAec_GetSkew(aecpc->resampler, skew, &aecpc->skew);
// if (retVal == -1) {
// aecpc->skew = 0;
// aecpc->lastError = AEC_BAD_PARAMETER_WARNING;
// }
// aecpc->skew /= aecpc->sampFactor*nrOfSamples;
// if (aecpc->skew < 1.0e-3 && aecpc->skew > -1.0e-3) {
// aecpc->resample = kAecFalse;
// }
// else {
// aecpc->resample = kAecTrue;
// }
// if (aecpc->skew < minSkewEst) {
// aecpc->skew = minSkewEst;
// }
// else if (aecpc->skew > maxSkewEst) {
// aecpc->skew = maxSkewEst;
// }
//}
}
var nFrames = (short)(nrOfSamples / aecConfig.SamplesPerFrame);
var nBlocks10Ms = (short)(nFrames / aec.mult);
WebRtcUtil.WriteDebugMessage(String.Format("(C#) AEC 01 ECstartup = {0}", ECstartup));
if (ECstartup)
{
nmbrOfFilledBuffers = (short)(farendBuf.get_buffer_size() / aecConfig.SamplesPerFrame);
// The AEC is in the start up mode
// AEC is disabled until the soundcard buffer and farend buffers are OK
// Mechanism to ensure that the soundcard buffer is reasonably stable.
if (checkBuffSize)
{
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 (counter == 0)
{
firstVal = this.msInSndCardBuf;
sum = 0;
}
if (Math.Abs(firstVal - this.msInSndCardBuf) <
WebRtcUtil.WEBRTC_SPL_MAX((int)(0.2 * this.msInSndCardBuf), WebRtcConstants.sampMsNb))
{
sum += this.msInSndCardBuf;
counter++;
}
else
{
counter = 0;
}
if (counter * nBlocks10Ms >= 6)
{
// The farend buffer size is determined in blocks of 80 samples
// Use 75% of the average value of the soundcard buffer
bufSizeStart = (short)WebRtcUtil.WEBRTC_SPL_MIN((int)(0.75 * (sum * aec.mult) / (counter * 10)), WebRtcConstants.BUF_SIZE_FRAMES);
// buffersize has now been determined
checkBuffSize = false;
}
if (checkBufSizeCtr * nBlocks10Ms > 50)
{
// for really bad sound cards, don't disable echocanceller for more than 0.5 sec
bufSizeStart = (short)WebRtcUtil.WEBRTC_SPL_MIN((int)(0.75 * (this.msInSndCardBuf * aec.mult) / 10), WebRtcConstants.BUF_SIZE_FRAMES);
checkBuffSize = false;
}
}
// if checkBuffSize changed in the if-statement above
if (!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 == bufSizeStart)
{
ECstartup = false; // Enable the AEC
}
else if (nmbrOfFilledBuffers > bufSizeStart)
{
farendBuf.Flush(farendBuf.get_buffer_size() - bufSizeStart * aecConfig.SamplesPerFrame);
ECstartup = false;
}
}
}
else
{
// AEC is enabled
// Note only 1 block supported for nb and 2 blocks for wb
for (int i = 0; i < nFrames; i++)
{
nmbrOfFilledBuffers = (short)(farendBuf.get_buffer_size() / aecConfig.SamplesPerFrame);
// Check that there is data in the far end buffer
if (nmbrOfFilledBuffers > 0)
{
// Get the next 80 samples from the farend buffer
farendBuf.Read(farend, aecConfig.SamplesPerFrame);
// Always store the last frame for use when we run out of data
farendOld[i] = farend;
}
else
{
// We have no data so we use the last played frame
farend = farendOld[i];
}
// Call buffer delay estimator when all data is extracted,
// i.e. i = 0 for NB and i = 1 for WB or SWB
if ((i == 0 && splitSampFreq == 8000) ||
(i == 1 && (splitSampFreq == 16000)))
{
EstBufDelay(this.msInSndCardBuf);
}
// Call the AEC
var nearend80 = new short[aecConfig.SamplesPerFrame];
Buffer.BlockCopy(nearend, aecConfig.SamplesPerFrame * i * sizeof(short), nearend80, 0, aecConfig.SamplesPerFrame * sizeof(short));
aec.ProcessFrame(nearend80, farend, nearend80, knownDelay);
Buffer.BlockCopy(nearend80, 0, nearend, aecConfig.SamplesPerFrame * i * sizeof(short), aecConfig.SamplesPerFrame * sizeof(short));
}
}
}