private void SilenceGenerationRoutine(int bufferSize, WaveFormatEx format)
{
try
{
var buffer = new float[bufferSize * format.Channels];
var bufferDurationMs = bufferSize * 1000 / format.SampleRate;
while (_continueSilenceThread)
{
_audioClientForRendering.GetCurrentPadding(out var padding);
int numFramesAvailable = bufferSize - padding;
_audioRenderClient.GetBuffer(numFramesAvailable, out var nativeBuffer);
if (nativeBuffer != IntPtr.Zero)
{
Marshal.Copy(buffer, 0, nativeBuffer, numFramesAvailable * format.Channels);
_audioRenderClient.ReleaseBuffer(numFramesAvailable, AudioClientBufferFlags.None);
}
_stopReading.WaitOne(bufferDurationMs / 2);
}
}
catch (Exception e)
{
Log.Warning(e, "Error in Silence generator. Exiting");
}
}
private void CheckFormat(WaveFormatEx format)
{
if (format.WaveFormat != 65534 ||
format.SubFormat != new Guid("00000003-0000-0010-8000-00aa00389b71"))
{
throw new InvalidOperationException($"Unsupported DesktopAudio Format {format.WaveFormat} - {format.SubFormat}");
}
}
private void StartSilenceGeneration()
{
IntPtr mixFormatPtr = IntPtr.Zero;
try
{
Checked(_endpoint.Activate(ref IAudioClientId, ClsCtxEnum.All, IntPtr.Zero, out var obj), "Silence.Activate");
_audioClientForRendering = (IAudioClient)obj;
Checked(_audioClientForRendering.GetMixFormat(out mixFormatPtr), "Silence.GetMixFormat");
WaveFormatEx format = (WaveFormatEx)Marshal.PtrToStructure(mixFormatPtr, typeof(WaveFormatEx));
CheckFormat(format);
Checked(_audioClientForRendering.Initialize(AudioClientShareModeEnum.Shared, AudioClientStreamFlagsEnum.None, 10_000_000 * 5, 0, mixFormatPtr, Guid.Empty), "Silence.Initialize");
Checked(_audioClientForRendering.GetBufferSize(out var bufferSize), "Silence.GetBufferSize");
Checked(_audioClientForRendering.GetService(IAudioRenderClientId, out var renderObj), "Silence.GetService");
_audioRenderClient = (IAudioRenderClient)renderObj;
Checked(_audioClientForRendering.Start(), "Silence.Start");
_silenceThread = new Thread(() => SilenceGenerationRoutine(bufferSize, format));
_silenceThread.Name = "Silence generator";
_silenceThread.Start();
}
catch (Exception e)
{
ReleaseComObject(ref _audioClientForRendering);
ReleaseComObject(ref _audioRenderClient);
Core.LogError(e, "Faied to StartSilenceGeneration");
}
finally
{
if (mixFormatPtr != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(mixFormatPtr);
}
}
}
public WaveFormatEx Open()
{
StopSilenceThread();
Log.Information("Opening DesktopAudio");
IMMDeviceEnumerator deviceEnumerator = null;
IntPtr mixFormatPtr = IntPtr.Zero;
try
{
bool render = true;
deviceEnumerator = Activator.CreateInstance(typeof(MMDeviceEnumerator)) as IMMDeviceEnumerator;
var res = deviceEnumerator.GetDefaultAudioEndpoint(
render ? DataFlowEnum.Render : DataFlowEnum.Capture,
render ? RoleEnum.Console : RoleEnum.Communications,
out _endpoint);
if (render)
{
StartSilenceGeneration();
}
Checked(_endpoint.Activate(ref IAudioClientId, ClsCtxEnum.All, IntPtr.Zero, out var obj), "Activate");
_audioClient = (IAudioClient)obj;
Checked(_audioClient.GetMixFormat(out mixFormatPtr), "GetMixFormat");
WaveFormatEx outputFormat = (WaveFormatEx)Marshal.PtrToStructure(mixFormatPtr, typeof(WaveFormatEx));
if (!render) // for render it is checked in the StartSilenceGeneration();
{
CheckFormat(outputFormat);
}
_bytesPerFrame = outputFormat.BlockAlign;
var flags = AudioClientStreamFlagsEnum.StreamFlagsEventCallback | (render ? AudioClientStreamFlagsEnum.StreamFlagsLoopback : AudioClientStreamFlagsEnum.None);
Checked(_audioClient.Initialize(AudioClientShareModeEnum.Shared, flags, 10_000_000 * 5, 0, mixFormatPtr, Guid.Empty), "Initialize");
Checked(_audioClient.GetService(IAudioCaptureClientId, out var captureObj), "GetService");
_audioCaptureClient = (IAudioCaptureClient)captureObj;
#pragma warning disable CS0618 // Type or member is obsolete
Checked(_audioClient.SetEventHandle(_dataAvailable.Handle), "SetEventHandle");
#pragma warning restore CS0618 // Type or member is obsolete
Checked(_audioClient.Start(), "Start");
return(outputFormat);
}
catch (Exception e)
{
Core.LogError(e, "Open desktop audio failed");
StopSilenceThread();
ReleaseComFields();
throw;
}
finally
{
if (mixFormatPtr != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(mixFormatPtr);
}
ReleaseComObject(ref deviceEnumerator);
}
}
