win32

需要先从麦克风中采样，代码样本可以参考官方示例： WASAPI Capture Shared Event Driven 

官方示例采样10s， 我们需要在WriteWaveFile函数下添加生成原始音频的代码。

//  Write the contents of a WAV file.  We take as input the data to write and the format of that data.
//
bool WriteWaveFile(HANDLE FileHandle, const BYTE *Buffer, const size_t BufferSize, const WAVEFORMATEX *WaveFormat)
{
    FILE* _file;
    int16_t* _data;
    _data = (int16_t*)Buffer;
    _file = fopen("utterance.raw", "wb +");
    fwrite(_data, 1, BufferSize, _file);
    fclose(_file);

    ...

得到utterance.raw原始音频样本之后，我们需要对其添加wav的头结构来重新生成wav文件

#include <Windows.h>
#include <stdio.h>
#include <MMDeviceAPI.h>
#include <AudioClient.h>
#include <assert.h>
#include <avrt.h>
#include <strsafe.h>
#include <fstream> 

using namespace std;

#pragma warning(disable:4996)

struct WAVEHEADER
{
    DWORD   dwRiff;                     // "RIFF"
    DWORD   dwSize;                     // Size
    DWORD   dwWave;                     // "WAVE"
    DWORD   dwFmt;                      // "fmt "
    DWORD   dwFmtSize;                  // Wave Format Size
};

const BYTE WaveHeader[] =
{
    'R',   'I',   'F',   'F',  0x00,  0x00,  0x00,  0x00, 'W',   'A',   'V',   'E',   'f',   'm',   't',   ' ', 0x00, 0x00, 0x00, 0x00
};

const BYTE WaveData[] = { 'd', 'a', 't', 'a' };

bool WriteWaveFile(HANDLE FileHandle, const BYTE* Buffer, const size_t BufferSize, WAVEFORMATEX* WaveFormat)
{
    DWORD waveFileSize = sizeof(WAVEHEADER) + sizeof(WAVEFORMATEX) + WaveFormat->cbSize + sizeof(WaveData) + sizeof(DWORD) + static_cast<DWORD>(BufferSize);
    BYTE* waveFileData = new (std::nothrow) BYTE[waveFileSize];
    BYTE* waveFilePointer = waveFileData;
    WAVEHEADER* waveHeader = reinterpret_cast<WAVEHEADER*>(waveFileData);

    if (waveFileData == NULL)
    {
        printf("Unable to allocate %d bytes to hold output wave data
", waveFileSize);
        return false;
    }

    //
    //  Copy in the wave header - we'll fix up the lengths later.
    //
    CopyMemory(waveFilePointer, WaveHeader, sizeof(WaveHeader));
    waveFilePointer += sizeof(WaveHeader);

    //
    //  Update the sizes in the header.
    //
    waveHeader->dwSize = waveFileSize - (2 * sizeof(DWORD));
    waveHeader->dwFmtSize = sizeof(WAVEFORMATEX) + WaveFormat->cbSize;

    //
    //  Next copy in the WaveFormatex structure.
    //
    CopyMemory(waveFilePointer, WaveFormat, sizeof(WAVEFORMATEX) + WaveFormat->cbSize);
    waveFilePointer += sizeof(WAVEFORMATEX) + WaveFormat->cbSize;


    //
    //  Then the data header.
    //
    CopyMemory(waveFilePointer, WaveData, sizeof(WaveData));
    waveFilePointer += sizeof(WaveData);
    *(reinterpret_cast<DWORD*>(waveFilePointer)) = static_cast<DWORD>(BufferSize);
    waveFilePointer += sizeof(DWORD);

    //
    //  And finally copy in the audio data.
    // 

    CopyMemory(waveFilePointer, Buffer, BufferSize);
    //
    //  Last but not least, write the data to the file.
    //
    DWORD bytesWritten;
    if (!WriteFile(FileHandle, waveFileData, waveFileSize, &bytesWritten, NULL))
    {
        printf("Unable to write wave file: %d
", GetLastError());
        delete[]waveFileData;
        return false;
    }

    if (bytesWritten != waveFileSize)
    {
        printf("Failed to write entire wave file
");
        delete[]waveFileData;
        return false;
    }
    delete[]waveFileData;
    return true;
}

//
//  Write the captured wave data to an output file so that it can be examined later.
//
void SaveWaveData(BYTE* CaptureBuffer, size_t BufferSize, WAVEFORMATEX* WaveFormat)
{
    wchar_t waveFileName[MAX_PATH];
    HRESULT hr = StringCbCopy(waveFileName, sizeof(waveFileName), L"WASAPICaptureEventDriven-");
    if (SUCCEEDED(hr))
    {
        GUID testGuid;
        if (SUCCEEDED(CoCreateGuid(&testGuid)))
        {
            wchar_t* guidString;
            if (SUCCEEDED(StringFromCLSID(testGuid, &guidString)))
            {
                hr = StringCbCat(waveFileName, sizeof(waveFileName), guidString);
                if (SUCCEEDED(hr))
                {
                    hr = StringCbCat(waveFileName, sizeof(waveFileName), L".WAV");
                    if (SUCCEEDED(hr))
                    {
                        HANDLE waveHandle = CreateFile(waveFileName, GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS,
                            FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN,
                            NULL);
                        if (waveHandle != INVALID_HANDLE_VALUE)
                        {
                            if (WriteWaveFile(waveHandle, CaptureBuffer, BufferSize, WaveFormat))
                            {
                                printf("Successfully wrote WAVE data to %S
", waveFileName);
                            }
                            else
                            {
                                printf("Unable to write wave file
");
                            }
                            CloseHandle(waveHandle);
                        }
                        else
                        {
                            printf("Unable to open output WAV file %S: %d
", waveFileName, GetLastError());
                        }
                    }
                }
                CoTaskMemFree(guidString);
            }
        }
    }
}

int main()
{
    long buffersize = 3528000;// For 10s audio sample, we can set the value of buffersize to 3528000
    BYTE* captureBuffer = new (std::nothrow) BYTE[buffersize]; 
    
    FILE* _file;
    _file = fopen("utterance.raw", "rb"); //raw audio path
    fread(captureBuffer, 1, buffersize, _file);
    fclose(_file);

    WAVEFORMATEX wavformat;
    wavformat.wFormatTag = WAVE_FORMAT_IEEE_FLOAT;
    wavformat.nChannels = 2;
    wavformat.nSamplesPerSec = 44100;
    wavformat.nAvgBytesPerSec = 352800;
    wavformat.nBlockAlign = 8;
    wavformat.wBitsPerSample = 32;
    wavformat.cbSize = 22;
    SaveWaveData(captureBuffer, buffersize, &wavformat);

    return 0;
}

通过将样本的路径添加给fopen，经过一些处理就可以得到了。

补充：

我们也可以使用ofstream来采样，代码见下：

//  Write the contents of a WAV file.  We take as input the data to write and the format of that data.
//
bool WriteWaveFile(HANDLE FileHandle, const BYTE *Buffer, const size_t BufferSize, const WAVEFORMATEX *WaveFormat)
{
    ofstream binaryFile("file.raw", ios::out | ios::binary);
    binaryFile.write((char*)Buffer, BufferSize);
    binaryFile.close();
    ...

再使用ifstream获取样本，添加wav的头结构来重新编码。

    ifstream infile("file.raw", std::ifstream::binary);
     // get size of file
    infile.seekg(0, infile.end);
    long size = infile.tellg();
    infile.seekg(0);

    BYTE* captureBuffer = new (std::nothrow) BYTE[size];
    
    infile.read((char*)captureBuffer, size);
    infile.close();

    WAVEFORMATEX wavformat;
    wavformat.wFormatTag = WAVE_FORMAT_IEEE_FLOAT;
    wavformat.nChannels = 2;
    wavformat.nSamplesPerSec = 44100;
    wavformat.nAvgBytesPerSec = 352800;
    wavformat.nBlockAlign = 8;
    wavformat.wBitsPerSample = 32;
    wavformat.cbSize = 22;
    SaveWaveData(captureBuffer, size, &wavformat);