C#音频采集 （笔记）

using System;
using System.Collections.Generic;
using System.Text;

using System.IO;
using System.Threading;
using Microsoft.DirectX;
using Microsoft.DirectX.DirectSound;
using System.Net.Sockets;
using System.Net;

namespace MatureVoice
{
class VoiceCapture
{
private MemoryStream memstream;//内存流
private SecondaryBuffer secBuffer;//辅助缓冲区
private int iNotifySize = 0;//通知大小
private int iBufferSize = 0;//捕捉缓冲区大小
private CaptureBuffer capturebuffer;//捕捉缓冲区对象
private AutoResetEvent notifyEvent;//通知事件
private Thread notifyThread;//通知线程
private int iNotifyNum=0;//通知个数
private Notify myNotify;//通知对象
private Capture capture;//捕捉设备对象
private Device PlayDev;//播放设备对象
private BufferDescription buffDiscript;
private Socket Client;
private EndPoint epServer;
private int iBufferOffset=0;//捕捉缓冲区位移
private IntPtr intptr;//窗口句柄

public IntPtr Intptr
{
set
{
intptr = value;
}
}

public int NotifySize
{
set
{
iNotifySize = value;
}

}

public int NotifyNum
{
set
{
iNotifyNum = value;
}
}

public Socket LocalSocket
{
set
{
Client = value;
}
}

public EndPoint RemoteEndPoint
{
set
{
epServer = value;
}
}

/// <summary>
/// 初始化相关操作
/// </summary>
public void InitVoice()
{//初始化声音相关设置：（1）捕捉缓冲区（2）播放缓冲区
if (!CreateCaputerDevice())
{
throw new Exception();
}//建立设备对象
CreateCaptureBuffer();//建立缓冲区对象
CreateNotification();//设置通知及事件
//======（2）==============
if (!CreatePlayDevice())
{
throw new Exception();
}
CreateSecondaryBuffer();
}

/// <summary>
/// 启动声音采集
/// </summary>
public void StartVoiceCapture()
{
capturebuffer.Start(true);//true表示设置缓冲区为循环方式，开始捕捉
}

/// <summary>
/// 创建用于播放的音频设备对象
/// </summary>
/// <returns>创建成功返回true</returns>
private bool CreatePlayDevice()
{
DevicesCollection dc = new DevicesCollection();
Guid g;
if (dc.Count > 0)
{
g = dc[0].DriverGuid;
}
else
{ return false; }
PlayDev = new Device(g);
PlayDev.SetCooperativeLevel(intptr, CooperativeLevel.Normal);
return true;
}

/// <summary>
/// 创建辅助缓冲区
/// </summary>
private void CreateSecondaryBuffer()
{
buffDiscript = new BufferDescription();
WaveFormat mWavFormat = SetWaveFormat();
buffDiscript.Format = mWavFormat;
iNotifySize = mWavFormat.AverageBytesPerSecond / iNotifyNum;//设置通知大小
iBufferSize = iNotifyNum * iNotifySize;
buffDiscript.BufferBytes = iBufferSize;
buffDiscript.ControlPan = true;
buffDiscript.ControlFrequency = true;
buffDiscript.ControlVolume = true;
buffDiscript.GlobalFocus = true;
secBuffer = new SecondaryBuffer(buffDiscript, PlayDev);
byte[] bytMemory = new byte[100000];
memstream = new MemoryStream(bytMemory, 0, 100000, true, true);
//g729 = new G729();
//g729.InitalizeEncode();
//g729.InitalizeDecode();
}

/// <summary>
/// 创建捕捉设备对象
/// </summary>
/// <returns>如果创建成功返回true</returns>
private bool CreateCaputerDevice()
{
//首先要玫举可用的捕捉设备
CaptureDevicesCollection capturedev = new CaptureDevicesCollection();
Guid devguid;
if (capturedev.Count > 0)
{
devguid = capturedev[0].DriverGuid;
}
else
{
System.Windows.Forms.MessageBox.Show("当前没有可用于音频捕捉的设备", "系统提示");
return false;
}
//利用设备GUID来建立一个捕捉设备对象
capture = new Capture(devguid);
return true;
}

/// <summary>
/// 创建捕捉缓冲区对象
/// </summary>
private void CreateCaptureBuffer()
{
//想要创建一个捕捉缓冲区必须要两个参数：缓冲区信息（描述这个缓冲区中的格式等），缓冲设备。
WaveFormat mWavFormat = SetWaveFormat();
CaptureBufferDescription bufferdescription = new CaptureBufferDescription();
bufferdescription.Format = mWavFormat;//设置缓冲区要捕捉的数据格式
iNotifySize = mWavFormat.AverageBytesPerSecond / iNotifyNum;//1秒的数据量/设置的通知数得到的每个通知大小小于0.2s的数据量，话音延迟小于200ms为优质话音
iBufferSize = iNotifyNum * iNotifySize;
bufferdescription.BufferBytes = iBufferSize;
bufferdescription.ControlEffects = true;
bufferdescription.WaveMapped = true;
capturebuffer = new CaptureBuffer(bufferdescription, capture);//建立设备缓冲区对象

}

//设置通知
private void CreateNotification()
{
BufferPositionNotify[] bpn = new BufferPositionNotify[iNotifyNum];//设置缓冲区通知个数
//设置通知事件
notifyEvent = new AutoResetEvent(false);
notifyThread = new Thread(RecoData);//通知触发事件
notifyThread.IsBackground = true;
notifyThread.Start();
for (int i = 0; i < iNotifyNum; i++)
{
bpn[i].Offset = iNotifySize + i * iNotifySize - 1;//设置具体每个的位置
bpn[i].EventNotifyHandle = notifyEvent.Handle;
}
myNotify = new Notify(capturebuffer);
myNotify.SetNotificationPositions(bpn);

}

//线程中的事件
private void RecoData()
{
while (true)
{
// 等待缓冲区的通知消息
notifyEvent.WaitOne(Timeout.Infinite, true);
// 录制数据
RecordCapturedData(Client,epServer);
}
}

//真正转移数据的事件，其实就是把数据传送到网络上去。
private void RecordCapturedData(Socket Client,EndPoint epServer )
{
byte[] capturedata = null;
int readpos = 0, capturepos = 0, locksize = 0;
capturebuffer.GetCurrentPosition(out capturepos, out readpos);
locksize = readpos - iBufferOffset;//这个大小就是我们可以安全读取的大小
if (locksize == 0)
{
return;
}
if (locksize < 0)
{//因为我们是循环的使用缓冲区，所以有一种情况下为负：当文以载读指针回到第一个通知点，而Ibuffeoffset还在最后一个通知处
locksize += iBufferSize;
}
capturedata = (byte[])capturebuffer.Read(iBufferOffset, typeof(byte), LockFlag.FromWriteCursor, locksize);
//capturedata = g729.Encode(capturedata);//语音编码
try
{
Client.SendTo(capturedata, epServer);//传送语音
}
catch
{
throw new Exception();
}
iBufferOffset += capturedata.Length;
iBufferOffset %= iBufferSize;//取模是因为缓冲区是循环的。
}

private int intPosWrite = 0;//内存流中写指针位移
private int intPosPlay = 0;//内存流中播放指针位移
private int intNotifySize = 5000;//设置通知大小

/// <summary>
/// 从字节数组中获取音频数据，并进行播放
/// </summary>
/// <param name="intRecv">字节数组长度</param>
/// <param name="bytRecv">包含音频数据的字节数组</param>
public void GetVoiceData(int intRecv, byte[] bytRecv)
{
//intPosWrite指示最新的数据写好后的末尾。intPosPlay指示本次播放开始的位置。
if (intPosWrite + intRecv <= memstream.Capacity)
{//如果当前写指针所在的位移+将要写入到缓冲区的长度小于缓冲区总大小
if ((intPosWrite - intPosPlay >= 0 && intPosWrite - intPosPlay < intNotifySize) || (intPosWrite - intPosPlay < 0 && intPosWrite - intPosPlay + memstream.Capacity < intNotifySize))
{
memstream.Write(bytRecv, 0, intRecv);
intPosWrite += intRecv;

}
else if (intPosWrite - intPosPlay >= 0)
{//先存储一定量的数据，当达到一定数据量时就播放声音。
buffDiscript.BufferBytes = intPosWrite - intPosPlay;//缓冲区大小为播放指针到写指针之间的距离。
SecondaryBuffer sec = new SecondaryBuffer(buffDiscript, PlayDev);//建立一个合适的缓冲区用于播放这段数据。
memstream.Position = intPosPlay;//先将memstream的指针定位到这一次播放开始的位置
sec.Write(0, memstream, intPosWrite - intPosPlay, LockFlag.FromWriteCursor);
sec.Play(0, BufferPlayFlags.Default);
memstream.Position = intPosWrite;//写完后重新将memstream的指针定位到将要写下去的位置。
intPosPlay = intPosWrite;
}
else if (intPosWrite - intPosPlay < 0)
{
buffDiscript.BufferBytes = intPosWrite - intPosPlay + memstream.Capacity;//缓冲区大小为播放指针到写指针之间的距离。
SecondaryBuffer sec = new SecondaryBuffer(buffDiscript, PlayDev);//建立一个合适的缓冲区用于播放这段数据。
memstream.Position = intPosPlay;
sec.Write(0, memstream, memstream.Capacity - intPosPlay, LockFlag.FromWriteCursor);
memstream.Position = 0;
sec.Write(memstream.Capacity - intPosPlay, memstream, intPosWrite, LockFlag.FromWriteCursor);
sec.Play(0, BufferPlayFlags.Default);
memstream.Position = intPosWrite;
intPosPlay = intPosWrite;
}
}
else
{//当数据将要大于memstream可容纳的大小时
int irest = memstream.Capacity - intPosWrite;//memstream中剩下的可容纳的字节数。
memstream.Write(bytRecv, 0, irest);//先写完这个内存流。
memstream.Position = 0;//然后让新的数据从memstream的0位置开始记录
memstream.Write(bytRecv, irest, intRecv - irest);//覆盖旧的数据
intPosWrite = intRecv - irest;//更新写指针位置。写指针指示下一个开始写入的位置而不是上一次结束的位置，因此不用减一
}
}

/// <summary>
/// 设置音频格式，如采样率等
/// </summary>
/// <returns>设置完成后的格式</returns>
private WaveFormat SetWaveFormat()
{
WaveFormat format = new WaveFormat();
format.FormatTag = WaveFormatTag.Pcm;//设置音频类型
format.SamplesPerSecond = 11025;//采样率（单位：赫兹）典型值：11025、22050、44100Hz
format.BitsPerSample = 16;//采样位数
format.Channels = 1;//声道
format.BlockAlign = (short)(format.Channels * (format.BitsPerSample / 8));//单位采样点的字节数
format.AverageBytesPerSecond = format.BlockAlign * format.SamplesPerSecond;

return format;
//按照以上采样规格，可知采样1秒钟的字节数为22050*2=44100B 约为 43K
}

/// <summary>
/// 停止语音采集
/// </summary>
public void Stop()
{
capturebuffer.Stop();
if (notifyEvent != null)
{
notifyEvent.Set();
}
if (notifyThread != null && notifyThread.IsAlive == true)
{
notifyThread.Abort();
}
}
}