public async Task Start()
{
m_isFlushing = false;
m_isRunning = false;
m_waveBufferReader = null;
var settings = new AudioGraphSettings(AudioRenderCategory.Media);
var result = await AudioGraph.CreateAsync(settings);
if (result.Status != AudioGraphCreationStatus.Success)
{
throw new Exception("AudioGraph creation error: " + result.Status);
}
m_audioGraph = result.Graph;
var outputDeviceResult = await m_audioGraph.CreateDeviceOutputNodeAsync();
if (outputDeviceResult.Status != AudioDeviceNodeCreationStatus.Success)
{
throw new Exception("Unable to create audio playback device: " + result.Status);
}
m_deviceOutputNode = outputDeviceResult.DeviceOutputNode;
// Create the FrameInputNode at the same format as the graph,
var nodeEncodingProperties = m_audioGraph.EncodingProperties;
nodeEncodingProperties.ChannelCount = 1;
nodeEncodingProperties.SampleRate = 16000;
m_frameInputNode = m_audioGraph.CreateFrameInputNode(nodeEncodingProperties);
m_frameInputNode.AddOutgoingConnection(m_deviceOutputNode);
m_frameInputNode.QuantumStarted += OnQuantumStarted;
m_isRunning = true;
m_isFlushing = false;
m_audioGraph.Start();
}
private unsafe AudioFrame GenerateAudioData(int samples)
{
var frame = new AudioFrame((uint)samples * sizeof(float));
try
{
using (var buffer = frame.LockBuffer(AudioBufferAccessMode.Read))
using (var reference = buffer.CreateReference())
{
byte * dataInBytes;
uint capacity;
float *dataInFloat;
// Get the buffer from the AudioFrame
((IMemoryBufferByteAccess)reference).GetBuffer(out dataInBytes, out capacity);
dataInFloat = (float *)dataInBytes;
var sampleIndex = 0;
while ((m_audioData.Count() > 0 || m_waveBufferReader != null) && sampleIndex < samples)
{
// extract the next audio buffer from the queue
if (m_waveBufferReader == null)
{
m_audioDataMutex.WaitOne();
m_waveBufferReader = WaveBufferReader.Create(m_audioData[0]);
m_audioData.RemoveAt(0);
m_audioDataMutex.ReleaseMutex();
}
// read samples from WaveBufferReader until output buffer is full
// or input buffer is empty
var eof = false;
while (sampleIndex < samples && !eof)
{
var temp = m_waveBufferReader.ReadShort(ref eof);
if (!eof)
{
dataInFloat[sampleIndex++] = temp / 32767.0f;
}
else
{
// current reader is empty so delete it
m_waveBufferReader = null;
}
}
}
// fill remainder of buffer with silence
while (sampleIndex < samples)
{
dataInFloat[sampleIndex++] = 0.0f;
// check if we are done flushing audio after Stop()
if (!m_isRunning && m_isFlushing && m_audioData.Count() == 0 && m_waveBufferReader == null)
{
m_isFlushing = false;
}
}
}
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
}
return(frame);
}
