public AudioContext(AudioFormat audioFormat, IAudioFilter resampler, IDtxFilter dtxFilter, IAudioTwoWayFilter speechEnhancer, IAudioEncoder encoder)
{
AudioFormat = audioFormat;
Resampler = resampler;
SpeechEnhancementStack = speechEnhancer;
Encoder = encoder;
DtxFilter = dtxFilter;
ResampleBuffer = new byte[audioFormat.BytesPerFrame];
CancelBuffer = new short[audioFormat.SamplesPerFrame];
EncodeBuffer = new short[audioFormat.SamplesPerFrame];
SendBuffer = new short[audioFormat.SamplesPerFrame];
}
private void TransmitAudio()
{
while (_audioEncodeResetEvent.WaitOne() && _isActive)
{
_audioEncodeResetEvent.Reset();
while (_audioFrames.Count > 0)
{
AudioFrame audioFrame;
lock (_audioFrames)
{
audioFrame = _audioFrames.Dequeue();
}
if (audioFrame == null)
{
continue;
}
// Cancel any echo onto the audioCancelBuffer.
var audioContext = audioFrame.AudioContext;
var frame = audioFrame.Samples;
_lastSpeechEnhancementStack = audioContext.SpeechEnhancementStack;
LastSpeechEnhancementName = _lastSpeechEnhancementStack.InstanceName;
_lastSpeechEnhancementStack.Write(frame);
bool moreFrames;
do
{
if (_lastSpeechEnhancementStack.Read(audioContext.CancelBuffer, out moreFrames))
{
if (!MediaConfig.PlayEchoCancelledSound)
{
Buffer.BlockCopy(frame, 0, audioContext.CancelBuffer, 0, frame.Length);
}
_cancelledStatistics.LatestFrame = audioContext.CancelBuffer;
if (OtherMembersInRoom)
{
PrepareAndSendAudioPacket(audioContext, audioContext.CancelBuffer);
}
}
} while (moreFrames);
}
}
}
public AudioContext GetAudioContext()
{
var resampler = new ResampleFilter(rawAudioFormat, transmittedAudioFormat);
var conferenceDtx = new DtxFilter(transmittedAudioFormat);
IAudioTwoWayFilter enhancer = null;
switch (enhancementStack)
{
case SpeechEnhancementStack.None:
enhancer = new NullEchoCancelFilter(mediaConfig.ExpectedAudioLatency, mediaConfig.FilterLength, transmittedAudioFormat, AudioFormat.Default);
break;
case SpeechEnhancementStack.Speex:
enhancer = new SpeexEchoCanceller2(mediaConfig, transmittedAudioFormat, AudioFormat.Default);
break;
case SpeechEnhancementStack.WebRtc:
enhancer = new WebRtcFilter(mediaConfig.ExpectedAudioLatency, mediaConfig.FilterLength, transmittedAudioFormat, AudioFormat.Default, mediaConfig.EnableAec, mediaConfig.EnableDenoise, mediaConfig.EnableAgc);
break;
}
IAudioEncoder encoder = null;
switch (codecType)
{
case AudioCodecType.G711M:
encoder = new G711MuLawEncoder(transmittedAudioFormat);
break;
case AudioCodecType.Speex:
encoder = new SpeexEncoder(transmittedAudioFormat);
break;
}
var ctx = new AudioContext(transmittedAudioFormat, resampler, conferenceDtx, enhancer, encoder);
return(ctx);
}
public SpeexPreprocessFilter(int samplesPerFrame, int samplesPerSecond, MediaConfig config, IAudioTwoWayFilter echoCancelFilter, string instanceName = "")
{
this.samplesPerSecond = samplesPerSecond;
#if SILVERLIGHT
st = this;
InstanceName = instanceName;
st.config = config;
speex_preprocess_state_init(samplesPerFrame, samplesPerSecond);
AgcLevel = 8000;
DereverbEnabled = false;
// ks 3/14/11 - VAD is supposedly a "kludge" right now, i.e., it's based on the overall power of the frame,
// and that's it. See http://lists.xiph.org/pipermail/speex-dev/2006-March/004271.html for the "fix" that eventually
// made its way into Speex as the "kludge". But turning it on seems to help, especially with AGC.
VadEnabled = true;
// ks 3/14/11 - Adjusted these, because the defaults amplify background noise too much.
// See http://lists.xiph.org/pipermail/speex-dev/2007-May/005696.html
AgcMaxGain = 15; // Default is 30
// NoiseSuppression = -30; // Default is -15. Recommended is -30, but that sounds awful in my environment.
EchoState = echoCancelFilter as SpeexEchoCanceller2; // Will store null if the provided echo canceller isn't a Speex echo canceller, which is what we want.
#endif
}
