/// <summary>
/// Converts an IEEE Floating Point audio buffer into a 16bit PCM compatible buffer.
/// </summary>
/// <param name="inputBuffer">The buffer in IEEE Floating Point format.</param>
/// <param name="length">The number of bytes in the buffer.</param>
/// <param name="format">The WaveFormat of the buffer.</param>
/// <returns>A byte array that represents the given buffer converted into PCM format.</returns>
/// source: https://stackoverflow.com/questions/65467635/converting-wasapiloopbackcapture-buffer-to-pcm
private static byte[] _ToPcm16(byte[] inputBuffer, int length, WaveFormat format)
{
if (length == 0)
{
return(new byte[0]); // No bytes recorded, return empty array.
}
// Create a WaveStream from the input buffer.
using var memStream = new MemoryStream(inputBuffer, 0, length);
using var inputStream = new RawSourceWaveStream(memStream, format);
// Convert the input stream to a WaveProvider in 16bit PCM format with sample rate of 48000 Hz.
var convertedPCM = new SampleToWaveProvider16(
new WdlResamplingSampleProvider(
new WaveToSampleProvider(inputStream),
96000 / format.Channels)
);
byte[] convertedBuffer = new byte[length];
using var stream = new MemoryStream();
int read;
// Read the converted WaveProvider into a buffer and turn it into a Stream.
while ((read = convertedPCM.Read(convertedBuffer, 0, length)) > 0)
{
stream.Write(convertedBuffer, 0, read);
}
// Return the converted Stream as a byte array.
return(stream.ToArray());
}
public static void CreateWave(Stream oggStream, Stream wavStream)
{
VorbisWaveReader vorbisReader = new VorbisWaveReader(oggStream);
SampleToWaveProvider16 converter = new SampleToWaveProvider16(vorbisReader);
using (var writer = new WaveFileWriter(wavStream, converter.WaveFormat))
{
int loopCount = 0;
var buffer = new byte[converter.WaveFormat.AverageBytesPerSecond * 4];
while (true)
{
loopCount++;
Debug.WriteLine("looped: " + loopCount.ToString());
int bytesRead = converter.Read(buffer, 0, buffer.Length);
if (bytesRead == 0)
{
// end of source provider
break;
}
// Write will throw exception if WAV file becomes too large
writer.Write(buffer, 0, bytesRead);
}
}
vorbisReader.Dispose();
}
protected override void FillBuffer(float[] buffer, int offset, int count)
{
if (Write && InputSignal.Value != null && FWriter != null)
{
var byteCount = count * 2;
if (FByteBuffer.Length < byteCount)
{
FByteBuffer = new byte[byteCount];
}
//read bytes from input
FWave16Provider.Read(FByteBuffer, 0, byteCount);
//write to stream
FWriter.Write(FByteBuffer, 0, byteCount);
SamplesWritten += count;
FFlushCounter += count;
if (FFlushCounter >= 32768)
{
FWriter.Flush();
FFlushCounter = 0;
}
FLastWriteState = true;
}
else
{
FFlushCounter = 0;
if (FLastWriteState)
{
FWriter.Flush();
FLastWriteState = false;
}
}
}
private byte[] ResampleLinux(byte[] pcm)
{
using (MemoryStream mem = new MemoryStream(pcm))
{
using (RawSourceWaveStream stream = new RawSourceWaveStream(mem, oldFormat))
{
Pcm16BitToSampleProvider sampleProvider = new Pcm16BitToSampleProvider(stream);
WdlResamplingSampleProvider resampedWavFile = new WdlResamplingSampleProvider(sampleProvider, newFormat.SampleRate);
SampleToWaveProvider16 sampleToWavProvider = new SampleToWaveProvider16(resampedWavFile);
int resampled_length = (int)((float)pcm.Length * ((float)newFormat.SampleRate / (float)oldFormat.SampleRate));
byte[] ret = new byte[resampled_length];
sampleToWavProvider.Read(ret, 0, resampled_length);
return(ret);
}
}
}
private byte[] convert32bitFloat48000HzStereoPCMTo16bitMonoPCM(WaveInEventArgs e, int sampleRate)
{
byte[] recorded_buf = e.Buffer;
int recorded_length = e.BytesRecorded;
byte[] result_buf = null;
int result_len = -1;
try
{
//// 生データを再生可能なデータに変換
var waveBufferResample = new BufferedWaveProvider(this._WaveIn.WaveFormat);
waveBufferResample.DiscardOnBufferOverflow = true;
waveBufferResample.ReadFully = false; // leave a buffer?
waveBufferResample.BufferLength = recorded_length;
var sampleStream = new WaveToSampleProvider(waveBufferResample);
// Downsample
var resamplingProvider = new WdlResamplingSampleProvider(sampleStream, sampleRate);
// Stereo to mono
var monoProvider = new StereoToMonoSampleProvider(resamplingProvider)
{
LeftVolume = 1f,
RightVolume = 1f
};
// Convert to 32bit float to 16bit PCM
var ieeeToPcm = new SampleToWaveProvider16(monoProvider);
waveBufferResample.AddSamples(recorded_buf, 0, recorded_length);
result_len = recorded_length / (2 * (48000 / sampleRate) * 2); // depth conv and sampling and ch conv
result_buf = new byte[result_len];
ieeeToPcm.Read(result_buf, 0, result_len);
}
catch (Exception ex)
{
Console.WriteLine(ex);
Console.WriteLine("exit...");
System.Windows.Forms.Application.Exit();
}
return(result_buf);
}
private byte[] ResampleAudioInput(byte[] audioBuffer, int audioBytesCount, bool debugMode)
{
if (debugMode)
{
inFileWriter.Write(audioBuffer, 0, audioBytesCount);
}
audioIeee.Write(audioBuffer, 0, audioBytesCount);
var numBytes = ((float)audioBytesCount / 4 / capture.WaveFormat.SampleRate) * outFormat.SampleRate;
byte[] outBuffer = new byte[Convert.ToInt32(Math.Ceiling(numBytes))];
var outBytesCount = audioPcm.Read(outBuffer, 0, outBuffer.Length);
if (debugMode)
{
outFileWriter.Write(outBuffer, 0, outBytesCount);
}
return(outBuffer);
}