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\n", 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\n", GetLastError());
delete[]waveFileData;
return false;
}
if (bytesWritten != waveFileSize)
{
printf("Failed to write entire wave file\n");
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\n", waveFileName);
}
else
{
printf("Unable to write wave file\n");
}
CloseHandle(waveHandle);
}
else
{
printf("Unable to open output WAV file %S: %d\n", 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);