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;  
            }  
        }  
  
  
        /// 
  
        /// 初始化相关操作  
        /// 
  
        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();  
        }  
  
        /// 
  
        /// 启动声音采集  
        /// 
  
        public void StartVoiceCapture()  
        {  
            capturebuffer.Start(true);//true表示设置缓冲区为循环方式，开始捕捉  
        }  
  
        /// 
  
        /// 创建用于播放的音频设备对象  
        /// 
  
        /// 创建成功返回true  
        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;  
        }  
  
        /// 
  
        /// 创建辅助缓冲区  
        /// 
  
        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();  
        }  
  
        /// 
  
        /// 创建捕捉设备对象  
        /// 
  
        /// 如果创建成功返回true  
        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;  
        }  
  
        /// 
  
        /// 创建捕捉缓冲区对象  
        /// 
  
        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  
  
        /// 
  
        /// 从字节数组中获取音频数据，并进行播放  
        /// 
  
        /// 字节数组长度  
        /// 包含音频数据的字节数组  
        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  
            }  
        }  
  
        /// 
  
        /// 设置音频格式，如采样率等  
        /// 
  
        /// 设置完成后的格式  
        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  
        }  
  
        /// 
  
        /// 停止语音采集  
        /// 
  
        public void Stop()  
        {  
            capturebuffer.Stop();  
            if (notifyEvent != null)  
            {  
                notifyEvent.Set();  
            }  
            if (notifyThread != null && notifyThread.IsAlive == true)  
            {  
                notifyThread.Abort();  
            }  
        }  
    }