Windows WaveIn 錄音

1. 設置採集音頻格式

   WAVEFORMATEX waveform; //採集音頻的格式，結構體
   waveform.wFormatTag = WAVE_FORMAT_PCM;//聲音格式爲PCM
   waveform.nSamplesPerSec = 8000;//採樣率，16000次/秒
   waveform.wBitsPerSample = 16;//採樣比特，16bits/次
   waveform.nChannels = 1;//採樣聲道數，2聲道
   waveform.nAvgBytesPerSec = 16000;//每秒的數據率，就是每秒能採集多少字節的數據
   waveform.nBlockAlign = 2;//一個塊的大小，採樣bit的字節數乘以聲道數
   waveform.cbSize = 0;//通常爲0

2. 提早準備好的錄音數據緩存

   m_pRecoderBuf = new unsigned char[20 * 1024];
   m_recoderNum = 20;
   m_recoderBufLen = 20 * 1024;
   m_pWaveHdr  = new WAVEHDR[20];
   memset(m_pRecoderBuf, 0, 20 * 1024);
   memset(m_pWaveHdr, 0, sizeof(WAVEHDR) * 20);

3. 打開錄音設備

   MMRESULT mmres = waveInOpen(&m_hWaveIn, WAVE_MAPPER, &waveform, (DWORD_PTR)WaveInProc, (DWORD_PTR)this, CALLBACK_FUNCTION );
   
   if(mmres != MMSYSERR_NOERROR)
   {
       // failed, try again.
       return;
   }

   WAVE_MAPPER表示系統會本身尋找合適的錄音設備。
4. 準備數據空間

   for (int i = 0; i < m_recoderNum; ++i)
   {
       m_pWaveHdr[i].lpData = (char*)m_pRecoderBuf + i * 1024;
       m_pWaveHdr[i].dwBufferLength = 1024;
       mmres = waveInPrepareHeader(m_hWaveIn, &m_pWaveHdr[i], sizeof(WAVEHDR));
       mmres = waveInAddBuffer(m_hWaveIn, &m_pWaveHdr[i], sizeof(WAVEHDR));
   }

5. 開始錄音並打開寫文件

   mmres = waveInStart(m_hWaveIn);
   
   SYSTEMTIME systemtime;
   GetLocalTime(&systemtime);
   char filename[256];
   sprintf_s(filename, 256, "%d-%d-%d_%d_%d_%d.wav", systemtime.wYear, systemtime.wMonth, systemtime.wDay, systemtime.wHour, systemtime.wMinute, systemtime.wSecond);
   m_pWavFile = wav_write_open(filename, 8000, 16, 1);

6. 要提早定義好數據接收回調函數，由於咱們用的是CALLBACK_FUNCTION

   static BOOL CALLBACK WaveInProc(HWAVEOUT hwo, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2);
   BOOL   WaveInProcImpl(HWAVEOUT hwo, UINT uMsg, DWORD dwParam1, DWORD dwParam2);

   函數裏的處理是：

   BOOL CAudioFileConvertDlg::WaveInProc(HWAVEOUT hwo, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2)
   {
       CAudioFileConvertDlg* pPlayer = (CAudioFileConvertDlg*)dwInstance;
   
       return pPlayer->WaveInProcImpl(hwo, uMsg, dwParam1, dwParam2);
   }
   
   BOOL CAudioFileConvertDlg::WaveInProcImpl(HWAVEOUT hwo, UINT uMsg, DWORD dwParam1, DWORD dwParam2)
   {
       // 忽略打開和關閉設備時的處理
       if(uMsg == WIM_DATA)
       {
           LPWAVEHDR pHdr = (LPWAVEHDR) dwParam1;
   
           MMRESULT mmres = waveInUnprepareHeader (m_hWaveIn, pHdr, sizeof(WAVEHDR));
           //處理數據
           if (NULL != m_pWavFile)
           {
               wav_write_data(m_pWavFile, (unsigned char *)(pHdr->lpData), pHdr->dwBytesRecorded);
           }
           //從新準備數據
           mmres = waveInPrepareHeader(m_hWaveIn, pHdr, sizeof(WAVEHDR));
           mmres = waveInAddBuffer(m_hWaveIn, pHdr, sizeof(WAVEHDR));
       }
   
       return TRUE;
   }

7. 關閉錄音並關閉wav寫文件

   MMRESULT mmres = waveInStop(m_hWaveIn);
   mmres = waveInClose(m_hWaveIn);
   wav_write_close(m_pWavFile);
   if (NULL != m_pRecoderBuf)
   {
       delete []m_pRecoderBuf;
       m_pRecoderBuf = NULL;
   }
   
   if (NULL != m_pWaveHdr)
   {
       delete []m_pWaveHdr;
       m_pWaveHdr = NULL;
   }