如何减少录音程序中CPU的消耗（c++）

Question

在 Internet 的帮助下，我编写了程序，可以在运行时始终从麦克风捕获音频。一切正常，但我需要减少CPU的费用，因为现在大约是30-35%。

int SoundCapture()
{
const int NUMPTS = 8000 * 1; // Sample rate * seconds
int sampleRate = 8000;
short int waveIn[NUMPTS];   // 'short int' is a 16-bit type; I request 16-bit samples below
                            // for 8-bit capture, you'd use 'unsigned char' or 'BYTE' 8-bit types
    HWAVEIN hWaveIn;
    WAVEFORMATEX waveform;
    WAVEHDR waveHeader;

waveform.wFormatTag = WAVE_FORMAT_PCM;  // simple, uncompressed format
waveform.nChannels = 1;                 //  1=mono, 2=stereo
waveform.nSamplesPerSec = 8000;
waveform.nAvgBytesPerSec = 8000;        // = nSamplesPerSec * n.Channels * wBitsPerSample/8
waveform.nBlockAlign = 1;               // = n.Channels * wBitsPerSample/8
waveform.wBitsPerSample = 8;            //  16 for high quality, 8 for telephone-grade
waveform.cbSize = 0;
MMRESULT result = waveInOpen(&hWaveIn, WAVE_MAPPER, &waveform, 0, 0, WAVE_FORMAT_DIRECT);
if (result)
{
    std::cout << "Something wrong with WaveOpen";
    std::cin.ignore(2);
    return 0;
}
// Set up and prepare header for input
waveHeader.lpData = (LPSTR)waveIn; //pointer to waveform buffer
waveHeader.dwBufferLength = NUMPTS;
waveHeader.dwBytesRecorded = 0;
waveHeader.dwUser = 0L;
waveHeader.dwFlags = 0L;
waveHeader.dwLoops = 0L;
waveInPrepareHeader(hWaveIn, &waveHeader, sizeof(WAVEHDR));

// Insert a wave input buffer
result = waveInAddBuffer(hWaveIn, &waveHeader, sizeof(WAVEHDR));
if (result)
{
    std::cout << "Something wrong with waveInAddBuffer";
    std::cin.ignore(2);
    return 0;
}
// Commence sampling input
time_t t = time(0);   // get time now
result = waveInStart(hWaveIn);
if (result)
{
    std::cout << "Something wrong with WaveStart";
    std::cin.ignore(2);
    return 0;
}


// Wait until finished recording
do {} while (waveInUnprepareHeader(hWaveIn, &waveHeader, sizeof(WAVEHDR)) == WAVERR_STILLPLAYING);
SaveWavFile(&waveHeader, t);
waveInClose(hWaveIn);
}

这是生成电荷的全部函数。我怎样才能减少它？或者也许我不能？使用 WindowsAPI 以外的其他捕获方法？

我尝试降低每秒样本数，但这并没有太大帮助。我想这与缓冲区有关，但需要任何提示。

干杯

Answer 1

正如我们所评论的，cpu 消耗是由于 do-while 循环中的主动等待。我建议使用 Event object in windows。但作为即时解决方案，我建议睡眠几毫秒（进行相关计算以确切知道什么是完美时间，正如@MSalters 在他的评论中所说）。

基于How do you make a program sleep in C++ on Win 32?，一个可能的解决方案是：

#include <windows.h>

//....
do {
   Sleep(X);
} 
while (waveInUnprepareHeader(hWaveIn, &waveHeader, sizeof(WAVEHDR)) == WAVERR_STILLPLAYING);
//....

如何减少录音程序中CPU的消耗（c++）

How to reduce consumption of CPU in audio recording program (c++)

c++

cpu

cpu-usage

audio-recording

audio-capture