在使用C#进行录音和播放录音功能上，使用NAudio是个不错的选择。
NAudio是个开源，相对功能比较全面的类库，它包含录音、播放录音、格式转换、混音调整等操作，具体可以去Github上看看介绍和源码，附：Git地址
我使用到的是录制和播放wav格式的音频，对应调用NAudio的WaveFileWriter和WaveFileReader类进行开发，从源码上看原理就是
- 根据上层传入的因为文件类型格式（mp3、wav等格式）定义进行创建流文件，并添加对应header和format等信息
- 调用WinAPI进行数据采集，实时读取其传入数据并保存至上述流文件中
- 保存
附：WaveFileWriter源码
using System;
using System.IO;
using NAudio.Wave.SampleProviders;
using NAudio.Utils;
// ReSharper disable once CheckNamespace
namespace NAudio.Wave
{
/// <summary>
/// This class writes WAV data to a .wav file on disk
/// </summary>
public class WaveFileWriter : Stream
{
private Stream outStream;
private readonly BinaryWriter writer;
private long dataSizePos;
private long factSampleCountPos;
private long dataChunkSize;
private readonly WaveFormat format;
private readonly string filename;
/// <summary>
/// Creates a 16 bit Wave File from an ISampleProvider
/// BEWARE: the source provider must not return data indefinitely
/// </summary>
/// <param name="filename">The filename to write to</param>
/// <param name="sourceProvider">The source sample provider</param>
public static void CreateWaveFile16(string filename, ISampleProvider sourceProvider)
{
CreateWaveFile(filename, new SampleToWaveProvider16(sourceProvider));
}
/// <summary>
/// Creates a Wave file by reading all the data from a WaveProvider
/// BEWARE: the WaveProvider MUST return 0 from its Read method when it is finished,
/// or the Wave File will grow indefinitely.
/// </summary>
/// <param name="filename">The filename to use</param>
/// <param name="sourceProvider">The source WaveProvider</param>
public static void CreateWaveFile(string filename, IWaveProvider sourceProvider)
{
using (var writer = new WaveFileWriter(filename, sourceProvider.WaveFormat))
{
var buffer = new byte[sourceProvider.WaveFormat.AverageBytesPerSecond * 4];
while (true)
{
int bytesRead = sourceProvider.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);
}
}
}
/// <summary>
/// Writes to a stream by reading all the data from a WaveProvider
/// BEWARE: the WaveProvider MUST return 0 from its Read method when it is finished,
/// or the Wave File will grow indefinitely.
/// </summary>
/// <param name="outStream">The stream the method will output to</param>
/// <param name="sourceProvider">The source WaveProvider</param>
public static void WriteWavFileToStream(Stream outStream, IWaveProvider sourceProvider)
{
using (var writer = new WaveFileWriter(new IgnoreDisposeStream(outStream), sourceProvider.WaveFormat))
{
var buffer = new byte[sourceProvider.WaveFormat.AverageBytesPerSecond * 4];
while(true)
{
var bytesRead = sourceProvider.Read(buffer, 0, buffer.Length);
if (bytesRead == 0)
{
// end of source provider
outStream.Flush();
break;
}
writer.Write(buffer, 0, bytesRead);
}
}
}
/// <summary>
/// WaveFileWriter that actually writes to a stream
/// </summary>
/// <param name="outStream">Stream to be written to</param>
/// <param name="format">Wave format to use</param>
public WaveFileWriter(Stream outStream, WaveFormat format)
{
this.outStream = outStream;
this.format = format;
writer = new BinaryWriter(outStream, System.Text.Encoding.UTF8);
writer.Write(System.Text.Encoding.UTF8.GetBytes("RIFF"));
writer.Write((int)0); // placeholder
writer.Write(System.Text.Encoding.UTF8.GetBytes("WAVE"));
writer.Write(System.Text.Encoding.UTF8.GetBytes("fmt "));
format.Serialize(writer);
CreateFactChunk();
WriteDataChunkHeader();
}
/// <summary>
/// Creates a new WaveFileWriter
/// </summary>
/// <param name="filename">The filename to write to</param>
/// <param name="format">The Wave Format of the output data</param>
public WaveFileWriter(string filename, WaveFormat format)
: this(new FileStream(filename, FileMode.Create, FileAccess.Write, FileShare.Read), format)
{
this.filename = filename;
}
private void WriteDataChunkHeader()
{
writer.Write(System.Text.Encoding.UTF8.GetBytes("data"));
dataSizePos = outStream.Position;
writer.Write((int)0); // placeholder
}
private void CreateFactChunk()
{
if (HasFactChunk())
{
writer.Write(System.Text.Encoding.UTF8.GetBytes("fact"));
writer.Write((int)4);
factSampleCountPos = outStream.Position;
writer.Write((int)0); // number of samples
}
}
private bool HasFactChunk()
{
return format.Encoding != WaveFormatEncoding.Pcm &&
format.BitsPerSample != 0;
}
/// <summary>
/// The wave file name or null if not applicable
/// </summary>
public string Filename => filename;
/// <summary>
/// Number of bytes of audio in the data chunk
/// </summary>
public override long Length => dataChunkSize;
/// <summary>
/// Total time (calculated from Length and average bytes per second)
/// </summary>
public TimeSpan TotalTime => TimeSpan.FromSeconds((double)Length / WaveFormat.AverageBytesPerSecond);
/// <summary>
/// WaveFormat of this wave file
/// </summary>
public WaveFormat WaveFormat => format;
/// <summary>
/// Returns false: Cannot read from a WaveFileWriter
/// </summary>
public override bool CanRead => false;
/// <summary>
/// Returns true: Can write to a WaveFileWriter
/// </summary>
public override bool CanWrite => true;
/// <summary>
/// Returns false: Cannot seek within a WaveFileWriter
/// </summary>
public override bool CanSeek => false;
/// <summary>
/// Read is not supported for a WaveFileWriter
/// </summary>
public override int Read(byte[] buffer, int offset, int count)
{
throw new InvalidOperationException("Cannot read from a WaveFileWriter");
}
/// <summary>
/// Seek is not supported for a WaveFileWriter
/// </summary>
public override long Seek(long offset, SeekOrigin origin)
{
throw new InvalidOperationException("Cannot seek within a WaveFileWriter");
}
/// <summary>
/// SetLength is not supported for WaveFileWriter
/// </summary>
/// <param name="value"></param>
public override void SetLength(long value)
{
throw new InvalidOperationException("Cannot set length of a WaveFileWriter");
}
/// <summary>
/// Gets the Position in the WaveFile (i.e. number of bytes written so far)
/// </summary>
public override long Position
{
get => dataChunkSize;
set => throw new InvalidOperationException("Repositioning a WaveFileWriter is not supported");
}
/// <summary>
/// Appends bytes to the WaveFile (assumes they are already in the correct format)
/// </summary>
/// <param name="data">the buffer containing the wave data</param>
/// <param name="offset">the offset from which to start writing</param>
/// <param name="count">the number of bytes to write</param>
[Obsolete("Use Write instead")]
public void WriteData(byte[] data, int offset, int count)
{
Write(data, offset, count);
}
/// <summary>
/// Appends bytes to the WaveFile (assumes they are already in the correct format)
/// </summary>
/// <param name="data">the buffer containing the wave data</param>
/// <param name="offset">the offset from which to start writing</param>
/// <param name="count">the number of bytes to write</param>
public override void Write(byte[] data, int offset, int count)
{
if (outStream.Length + count > UInt32.MaxValue)
throw new ArgumentException("WAV file too large", nameof(count));
outStream.Write(data, offset, count);
dataChunkSize += count;
}
private readonly byte[] value24 = new byte[3]; // keep this around to save us creating it every time
/// <summary>
/// Writes a single sample to the Wave file
/// </summary>
/// <param name="sample">the sample to write (assumed floating point with 1.0f as max value)</param>
public void WriteSample(float sample)
{
if (WaveFormat.BitsPerSample == 16)
{
writer.Write((Int16)(Int16.MaxValue * sample));
dataChunkSize += 2;
}
else if (WaveFormat.BitsPerSample == 24)
{
var value = BitConverter.GetBytes((Int32)(Int32.MaxValue * sample));
value24[0] = value[1];
value24[1] = value[2];
value24[2] = value[3];
writer.Write(value24);
dataChunkSize += 3;
}
else if (WaveFormat.BitsPerSample == 32 && WaveFormat.Encoding == WaveFormatEncoding.Extensible)
{
writer.Write(UInt16.MaxValue * (Int32)sample);
dataChunkSize += 4;
}
else if (WaveFormat.Encoding == WaveFormatEncoding.IeeeFloat)
{
writer.Write(sample);
dataChunkSize += 4;
}
else
{
throw new InvalidOperationException("Only 16, 24 or 32 bit PCM or IEEE float audio data supported");
}
}
/// <summary>
/// Writes 32 bit floating point samples to the Wave file
/// They will be converted to the appropriate bit depth depending on the WaveFormat of the WAV file
/// </summary>
/// <param name="samples">The buffer containing the floating point samples</param>
/// <param name="offset">The offset from which to start writing</param>
/// <param name="count">The number of floating point samples to write</param>
public void WriteSamples(float[] samples, int offset, int count)
{
for (int n = 0; n < count; n++)
{
WriteSample(samples[offset + n]);
}
}
/// <summary>
/// Writes 16 bit samples to the Wave file
/// </summary>
/// <param name="samples">The buffer containing the 16 bit samples</param>
/// <param name="offset">The offset from which to start writing</param>
/// <param name="count">The number of 16 bit samples to write</param>
[Obsolete("Use WriteSamples instead")]
public void WriteData(short[] samples, int offset, int count)
{
WriteSamples(samples, offset, count);
}
/// <summary>
/// Writes 16 bit samples to the Wave file
/// </summary>
/// <param name="samples">The buffer containing the 16 bit samples</param>
/// <param name="offset">The offset from which to start writing</param>
/// <param name="count">The number of 16 bit samples to write</param>
public void WriteSamples(short[] samples, int offset, int count)
{
// 16 bit PCM data
if (WaveFormat.BitsPerSample == 16)
{
for (int sample = 0; sample < count; sample++)
{
writer.Write(samples[sample + offset]);
}
dataChunkSize += (count * 2);
}
// 24 bit PCM data
else if (WaveFormat.BitsPerSample == 24)
{
for (int sample = 0; sample < count; sample++)
{
var value = BitConverter.GetBytes(UInt16.MaxValue * (Int32)samples[sample + offset]);
value24[0] = value[1];
value24[1] = value[2];
value24[2] = value[3];
writer.Write(value24);
}
dataChunkSize += (count * 3);
}
// 32 bit PCM data
else if (WaveFormat.BitsPerSample == 32 && WaveFormat.Encoding == WaveFormatEncoding.Extensible)
{
for (int sample = 0; sample < count; sample++)
{
writer.Write(UInt16.MaxValue * (Int32)samples[sample + offset]);
}
dataChunkSize += (count * 4);
}
// IEEE float data
else if (WaveFormat.BitsPerSample == 32 && WaveFormat.Encoding == WaveFormatEncoding.IeeeFloat)
{
for (int sample = 0; sample < count; sample++)
{
writer.Write((float)samples[sample + offset] / (float)(Int16.MaxValue + 1));
}
dataChunkSize += (count * 4);
}
else
{
throw new InvalidOperationException("Only 16, 24 or 32 bit PCM or IEEE float audio data supported");
}
}
/// <summary>
/// Ensures data is written to disk
/// Also updates header, so that WAV file will be valid up to the point currently written
/// </summary>
public override void Flush()
{
var pos = writer.BaseStream.Position;
UpdateHeader(writer);
writer.BaseStream.Position = pos;
}
#region IDisposable Members
/// <summary>
/// Actually performs the close,making sure the header contains the correct data
/// </summary>
/// <param name="disposing">True if called from <see>Dispose</see></param>
protected override void Dispose(bool disposing)
{
if (disposing)
{
if (outStream != null)
{
try
{
UpdateHeader(writer);
}
finally
{
// in a finally block as we don't want the FileStream to run its disposer in
// the GC thread if the code above caused an IOException (e.g. due to disk full)
outStream.Dispose(); // will close the underlying base stream
outStream = null;
}
}
}
}
/// <summary>
/// Updates the header with file size information
/// </summary>
protected virtual void UpdateHeader(BinaryWriter writer)
{
writer.Flush();
UpdateRiffChunk(writer);
UpdateFactChunk(writer);
UpdateDataChunk(writer);
}
private void UpdateDataChunk(BinaryWriter writer)
{
writer.Seek((int)dataSizePos, SeekOrigin.Begin);
writer.Write((UInt32)dataChunkSize);
}
private void UpdateRiffChunk(BinaryWriter writer)
{
writer.Seek(4, SeekOrigin.Begin);
writer.Write((UInt32)(outStream.Length - 8));
}
private void UpdateFactChunk(BinaryWriter writer)
{
if (HasFactChunk())
{
int bitsPerSample = (format.BitsPerSample * format.Channels);
if (bitsPerSample != 0)
{
writer.Seek((int)factSampleCountPos, SeekOrigin.Begin);
writer.Write((int)((dataChunkSize * 8) / bitsPerSample));
}
}
}
/// <summary>
/// Finaliser - should only be called if the user forgot to close this WaveFileWriter
/// </summary>
~WaveFileWriter()
{
System.Diagnostics.Debug.Assert(false, "WaveFileWriter was not disposed");
Dispose(false);
}
#endregion
}
}
WaveFileReader和WaveFileWriter相似，只是把写流文件变成了读流文件，具体可在源码中查看。
值得注意的是，在有需要对音频进行分析处理的需求时（如VAD）可以查看其DataAvailable事件，该事件会实时回调传递音频数据（byte[]），最后强调一点这个音频数据byte数组需要注意其写入时和读取时PCM所使用的bit数，PCM分别有8/16/24/32四种，在WaveFormat.BitsPerSample属性上可以查看，根据PCM不同类型这个byte数组的真实数据转换上也要转换不同类型，8bit是一个字节、16bit是两个字节、24.....32...等，在使用时根据这个进行对应转换才是正确的数值。
附PCM类型初始化对应部分代码：
public static ISampleProvider ConvertWaveProviderIntoSampleProvider(IWaveProvider waveProvider)
{
ISampleProvider sampleProvider;
if (waveProvider.WaveFormat.Encoding == WaveFormatEncoding.Pcm)
{
// go to float
if (waveProvider.WaveFormat.BitsPerSample == 8)
{
sampleProvider = new Pcm8BitToSampleProvider(waveProvider);
}
else if (waveProvider.WaveFormat.BitsPerSample == 16)
{
sampleProvider = new Pcm16BitToSampleProvider(waveProvider);
}
else if (waveProvider.WaveFormat.BitsPerSample == 24)
{
sampleProvider = new Pcm24BitToSampleProvider(waveProvider);
}
else if (waveProvider.WaveFormat.BitsPerSample == 32)
{
sampleProvider = new Pcm32BitToSampleProvider(waveProvider);
}
else
{
throw new InvalidOperationException("Unsupported bit depth");
}
}
else if (waveProvider.WaveFormat.Encoding == WaveFormatEncoding.IeeeFloat)
{
if (waveProvider.WaveFormat.BitsPerSample == 64)
sampleProvider = new WaveToSampleProvider64(waveProvider);
else
sampleProvider = new WaveToSampleProvider(waveProvider);
}
else
{
throw new ArgumentException("Unsupported source encoding");
}
return sampleProvider;
}
}
以上是查看源码和使用上的一些记录，具体录制和播放示例如下：示例
新接触，有些感悟，分享下