目的：Windows下wave API採集PCM

環境：

系統：Win10
環境：VS2015 64bit

操作步驟：

1. 匯入系統wave標頭檔案及庫

#include <mmsystem.h>   
#pragma comment(lib, "winmm.lib") 

2. 獲取音訊裝置資訊 - 確認是否有音訊輸入裝置

1. UINT WINAPI waveInGetNumDevs(void); //返回音訊輸入裝置的數量

2. MMRESULT WINAPI waveInGetDevCaps(   //獲取輸入裝置資訊
    _In_ UINT_PTR uDeviceID,
    _Out_writes_bytes_(cbwic) LPWAVEINCAPSW pwic,
    _In_ UINT cbwic
    );

3.
 
 示例：
    int iAudioDev = waveInGetNumDevs();    //獲取裝置數量
    printf("[Capture] input device Num:[%d]\n", iAudioDev);

    for (int i = 0; i < iAudioDev; i++)    //迴圈列印裝置的資訊
    {
        WAVEINCAPS wic;
        waveInGetDevCaps(i, &wic, sizeof(WAVEINCAPS));   //注意，i即為DeviceID
        printf("[Capture] DeviceNum:[%d], DevicePID:[%d], DeviceName：%s\n"
 
, i, wic.wPid, wic.szPname);
    }

ps: 實際測試筆記本可以獲取到兩個音訊輸入裝置，DeviceID分別為0和1。當在waveInOpen()開啟0的時候是系統聲音+麥克風採集;當在waveInOpen()開啟1的時候是麥克風採集，沒有系統音。

3. 開啟音訊裝置

1. typedef struct tWAVEFORMATEX    //音訊資訊結構體
{
    WORD wFormatTag; /* format type */
    WORD nChannels; /* number of channels (i.e. mono, stereo...) */
    DWORD nSamplesPerSec; /* sample rate */
 

    DWORD nAvgBytesPerSec; /* for buffer estimation */
    WORD nBlockAlign; /* block size of data */
    WORD wBitsPerSample; /* number of bits per sample of mono data */
    WORD cbSize; /* the count in bytes of the size of */
    /* extra information (after cbSize) */
} WAVEFORMATEX, *PWAVEFORMATEX, NEAR *NPWAVEFORMATEX, FAR *LPWAVEFORMATEX;

2. WINMMAPI MMRESULT WINAPI waveInOpen(  //開啟音訊裝置
    _Out_opt_ LPHWAVEIN phwi,
    _In_ UINT uDeviceID,
    _In_ LPCWAVEFORMATEX pwfx,
    _In_opt_ DWORD_PTR dwCallback,
    _In_opt_ DWORD_PTR dwInstance,
    _In_ DWORD fdwOpen
    );

3. 示例：
    HWAVEIN hWave;
    WAVEFORMATEX waveForm;   
    memset(&waveForm, 0, sizeof(WAVEFORMATEX));
    waveForm.wFormatTag = WAVE_FORMAT_PCM;   
    waveForm.nChannels = 1;     
    waveForm.nSamplesPerSec = 8000;   
    waveForm.nAvgBytesPerSec = waveForm.nChannels*waveForm.nSamplesPerSec*waveForm.wBitsPerSample / 8;
    waveForm.nBlockAlign = 4;
    waveForm.wBitsPerSample = 16;   
    waveForm.cbSize = 0;

    waveInOpen(&hWave, WAVE_MAPPER, &waveForm, (DWORD_PTR)waveCaptureProc, 0, CALLBACK_FUNCTION);   //waveInProc音訊採集回掉，在設定的回掉函式中獲取音訊資料，DeviceID可以預設設定為WAVE_MAPPER，自動選擇採集(系統音+麥克風，類似於 0), DeviceID設定為非0值，即是對應的麥克風聲音。

//回撥函式   
void CALLBACK waveCaptureProc(HWAVEIN hwi,
    UINT uMsg,
    DWORD_PTR dwInstance,
    DWORD_PTR dwParam1,
    DWORD_PTR dwParam2)
{
    LPWAVEHDR waveH = (LPWAVEHDR)dwParam1;  
    if ((WIM_DATA == uMsg))
    {
        fwrite(waveH->lpData, 1, waveH->dwBytesRecorded, fpInPCM);   //寫出資料
        printf("Capture:[%d]\n", waveH->dwBytesRecorded);
        waveInAddBuffer(hwi, waveH, sizeof(WAVEHDR));              //buffer重新放入採集佇列
    }
}

ps：回掉或者主執行緒可以做策略來實現錄音的停止控制

4. 裝置音訊緩衝區，並開始錄音

1. 填充WAVEHDR結構體。
2. WINMMAPI MMRESULT WINAPI waveInPrepareHeader( // 準備緩衝區
    _In_ HWAVEIN hwi,
    _Inout_updates_bytes_(cbwh) LPWAVEHDR pwh,
    _In_ UINT cbwh
    );
3. WINMMAPI MMRESULT WINAPI waveInAddBuffer( //新增buffer到音訊採集
    _In_ HWAVEIN hwi,
    _Inout_updates_bytes_(cbwh) LPWAVEHDR pwh,
    _In_ UINT cbwh
    );
4. WINMMAPI MMRESULT WINAPI waveInStart(_In_ HWAVEIN hwi);//開始錄音

示例：
#define FRAGMENT_SIZE 1024        // 設定快取區大小  
#define FRAGMENT_NUM 4            // 設定快取區個數  
static WAVEHDR waveHDR[FRAGMENT_NUM];  
for (int i = 0; i<FRAGMENT_NUM; i++)
{
    waveHDR[i].lpData = new char[FRAGMENT_SIZE];
    waveHDR[i].dwBufferLength = FRAGMENT_SIZE;
    waveHDR[i].dwBytesRecorded = 0;
    waveHDR[i].dwUser = NULL;
    waveHDR[i].dwFlags = 0;
    waveHDR[i].dwLoops = 1;
    waveHDR[i].lpNext = NULL;
    waveHDR[i].reserved = 0;

    waveInPrepareHeader(hWave, &waveHDR[i], sizeof(WAVEHDR));
    waveInAddBuffer(hWave, &waveHDR[i], sizeof(WAVEHDR));
}

waveInStart(hWave);

5. 錄音結束關閉

1. WINMMAPI MMRESULT WINAPI waveInStop(_In_ HWAVEIN hwi);
2. WINMMAPI MMRESULT WINAPI waveInReset(_In_ HWAVEIN hwi);
3. 釋放新增的緩衝區
4. WINMMAPI MMRESULT WINAPI waveInClose(_In_ HWAVEIN hwi);

示例：
waveInStop(hWave);
waveInReset(hWave);

for (int i = 0; i < FRAGMENT_NUM; i++)
{
    waveInUnprepareHeader(hWave, &waveHDR[i], sizeof(WAVEHDR));
    delete waveHDR[i].lpData;
    delete waveHDR[i].lpData = NULL;
}

waveInClose(hWave);