Question

我想录制麦克风音频输入，并且在一些小的时间延迟下，立即播放录制的声音。这将使用缓冲区队列连续完成。

我让代码运行到几乎连续播放麦克风音频输入的程度，但使用waveOut在整个音频输出中有很短但仍然明显的重复暂停。是什么导致这些烦人的停顿？以及如何删除它们？

另一个问题是，我没有使用任何像互斥量这样的东西，我依赖于waveIn和waveOut具有相同的采样率和相同数量的数据，所以希望waveOut始终遵循waveIn并且waveIn不会写入正在播放的缓冲区。这会是个问题吗？

这里是代码，它应该编译并运行。我只是让代码运行起来，而且远没有写得好。任何关于改进代码的评论都非常受欢迎。

    #include "stdafx.h"
    #include <Windows.h>
    #pragma comment(lib, "winmm.lib")
    #include <iostream>
    #include <fstream>
    #include <sstream>

    using namespace std;
    HANDLE hEvent_BufferReady;
    HANDLE hEvent_FinishedPlaying;
    #define Samplerate 44100
    #define nSec  1

    int _iBuf;
    int _iplaying;
    unsigned long result;


    HWAVEIN hWaveIn;
    HWAVEOUT hWaveOut;
    WAVEFORMATEX pFormat;

    enum { NUM_BUF = 3 };
    WAVEHDR _header [NUM_BUF];

    DWORD WINAPI RecordingWaitingThread(LPVOID ivalue)
    {
        while(1)
        {
        WaitForSingleObject(hEvent_BufferReady,INFINITE);


        result = waveInUnprepareHeader (hWaveIn, &_header[_iBuf], sizeof (WAVEHDR));
        _iplaying = _iBuf;
        result = waveOutPrepareHeader(hWaveOut, &_header[_iBuf], sizeof(WAVEHDR));
        result = waveOutWrite(hWaveOut, &_header[_iBuf], sizeof(WAVEHDR));   // play audio
        ++_iBuf;
        if (_iBuf == NUM_BUF)   _iBuf = 0;
        result = waveInPrepareHeader(hWaveIn, & _header[_iBuf], sizeof(WAVEHDR));
        result = waveInAddBuffer (hWaveIn, & _header[_iBuf], sizeof (WAVEHDR)); 
        }
        return 0;
    }

    DWORD WINAPI PlayingWaitingThread(LPVOID ivalue)
    {
        while(1){
            WaitForSingleObject(hEvent_FinishedPlaying,INFINITE);
            waveOutUnprepareHeader(hWaveOut, &_header[_iplaying], sizeof(WAVEHDR));
        }
    }

    static void CALLBACK waveOutProc(HWAVEOUT hWaveOut, UINT uMsg, DWORD dwInstance, DWORD dwParam1,DWORD dwParam2 )
    {
    if(uMsg != WOM_DONE)
    return;
    SetEvent(hEvent_FinishedPlaying);
    }


    void CALLBACK myWaveInProc(HWAVEIN hwi, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2)
    {
    if(uMsg != WIM_DATA)
    return;
    SetEvent(hEvent_BufferReady);
    }

    int main(int argc, _TCHAR* argv[])
    {

        hEvent_BufferReady=CreateEvent(NULL,FALSE, FALSE, NULL);
        hEvent_FinishedPlaying = CreateEvent(NULL,FALSE, FALSE, NULL);


        pFormat.wFormatTag = WAVE_FORMAT_PCM; // simple, uncompressed format
        pFormat.nChannels = 1; // 1=mono, 2=stereo
        pFormat.nSamplesPerSec = Samplerate; 
        pFormat.wBitsPerSample = 16; // 16 for high quality, 8 for telephone-grade
        pFormat.nBlockAlign = pFormat.nChannels*pFormat.wBitsPerSample/8; 
        pFormat.nAvgBytesPerSec = (pFormat.nSamplesPerSec)*(pFormat.nChannels)*(pFormat.wBitsPerSample)/8; 
        pFormat.cbSize=0;


        short int  *_pBuf;
        size_t bpbuff =4000;//= (pFormat.nSamplesPerSec) * (pFormat.nChannels) * (pFormat.wBitsPerSample)/8;
        _pBuf = new short int [bpbuff * NUM_BUF];

        result = waveInOpen(&hWaveIn, WAVE_MAPPER,&pFormat, (DWORD)myWaveInProc, 0L, CALLBACK_FUNCTION);
        result = waveOutOpen(&hWaveOut, WAVE_MAPPER, &pFormat, (DWORD_PTR)waveOutProc, 0, CALLBACK_FUNCTION);
        // initialize all headers in the queue
        for ( int i = 0; i < NUM_BUF; i++ )
        {
            _header[i].lpData = (LPSTR)&_pBuf [i * bpbuff];
            _header[i].dwBufferLength = bpbuff*sizeof(*_pBuf);
            _header[i].dwFlags = 0L;
            _header[i].dwLoops = 0L;
        }

        DWORD myThreadID;
        DWORD myThreadIDPlay;
        HANDLE hThread;
        HANDLE hThreadPlay;
        hThread = CreateThread(NULL, 0, RecordingWaitingThread,NULL,0,&myThreadID);
        hThreadPlay = CreateThread(NULL, 0, PlayingWaitingThread,NULL,0,&myThreadIDPlay);

        _iBuf = 0;

        waveInPrepareHeader(hWaveIn, & _header[_iBuf], sizeof(WAVEHDR));
        waveInAddBuffer (hWaveIn, & _header[_iBuf], sizeof (WAVEHDR));

        waveInStart(hWaveIn);

        getchar();
        waveInClose(hWaveIn);
        waveOutClose(hWaveOut);
        CloseHandle(hThread);
        CloseHandle(hThreadPlay);

        CloseHandle(hEvent_BufferReady);
        CloseHandle(hEvent_FinishedPlaying);

        return 0;
    }

Answer 1

您程序的问题在于您声明的 bpbuff 太小。只需尝试使用 size_t bpbuff = 4410; 声明它，您就会摆脱音频流中的所有这些重复中断。

顺便说一句，我认为您可以摆脱这些线程方法，使您的代码更简单，如下所示：

#include "stdafx.h"
#include <Windows.h>
#pragma comment(lib, "winmm.lib")
#include <iostream>
#include <fstream>
#include <sstream>

using namespace std;
#define Samplerate 44100

static HWAVEIN hWaveIn;
static HWAVEOUT hWaveOut;

enum { NUM_BUF = 3 };
WAVEHDR _header [NUM_BUF];

void CALLBACK myWaveInProc(HWAVEIN hwi, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2)
{
    static int _iBuf;
    waveOutWrite(hWaveOut, &_header[_iBuf], sizeof(WAVEHDR));   // play audio
    ++_iBuf;
    if (_iBuf == NUM_BUF)   _iBuf = 0;
    waveInAddBuffer (hWaveIn, & _header[_iBuf], sizeof (WAVEHDR)); 
}

int main(int argc, _TCHAR* argv[])
{
    WAVEFORMATEX pFormat;
    pFormat.wFormatTag = WAVE_FORMAT_PCM; // simple, uncompressed format
    pFormat.nChannels = 1; // 1=mono, 2=stereo
    pFormat.nSamplesPerSec = Samplerate; 
    pFormat.wBitsPerSample = 16; // 16 for high quality, 8 for telephone-grade
    pFormat.nBlockAlign = pFormat.nChannels*pFormat.wBitsPerSample/8; 
    pFormat.nAvgBytesPerSec = (pFormat.nSamplesPerSec)*(pFormat.nChannels)*(pFormat.wBitsPerSample)/8; 
    pFormat.cbSize=0;

    short int  *_pBuf;
    size_t bpbuff = 4410;//= (pFormat.nSamplesPerSec) * (pFormat.nChannels) * (pFormat.wBitsPerSample)/8;
    _pBuf = new short int [bpbuff * NUM_BUF];

    waveInOpen(&hWaveIn, WAVE_MAPPER,&pFormat, (DWORD)myWaveInProc, 0L, CALLBACK_FUNCTION);
    waveOutOpen(&hWaveOut, WAVE_MAPPER, &pFormat, (DWORD_PTR)nullptr, 0, CALLBACK_FUNCTION);
    // initialize all headers in the queue
    for ( int i = 0; i < NUM_BUF; i++ )
    {
        _header[i].lpData = (LPSTR)&_pBuf [i * bpbuff];
        _header[i].dwBufferLength = bpbuff*sizeof(*_pBuf);
        _header[i].dwFlags = 0L;
        _header[i].dwLoops = 0L;
        waveInPrepareHeader(hWaveIn, & _header[i], sizeof(WAVEHDR));
    }
    waveInAddBuffer (hWaveIn, & _header[0], sizeof (WAVEHDR));

    waveInStart(hWaveIn);

    getchar();
    waveInClose(hWaveIn);
    waveOutClose(hWaveOut);
    delete _pBuf;

    return 0;
}

这段代码用更少的代码执行完全相同的任务。干杯，伙计！

使用waveIn和waveOut

1 个答案: