波形音频 - waveOutWrite 发出断断续续的声音

Question

我正在尝试使用 Waveform Audio library 创建一个 C++ 程序，该程序将播放另一个程序提供的 AudioFrames（原始音频数据，每帧包含大约 1920 个字节）（现在我只是通过读取文件来模拟它作为音频帧）。从this thread 修改代码我能够制作完成这项工作的 SoundPlayer 类，但我得到的输出非常不稳定。更大的帧大小会变得更好，但即使帧大到 96000 字节，音频仍然每秒左右出现故障（我需要帧也比这小得多）。

我该如何解决这个问题？

Here 是我正在使用的测试文件。这是代码本身：

#include <windows.h>
#include <iostream>
#pragma comment(lib, "Winmm.lib")

constexpr int FRAME_SIZE_IN_BYTES = 1920;

struct AudioFrame
{
    char *Data;
    int DataSize;
};

class SoundPlayer
{
public:

    SoundPlayer()
    {
        // Initialize the sound format we will request from sound card
        m_waveFormat.wFormatTag = WAVE_FORMAT_PCM;     // Uncompressed sound format
        m_waveFormat.nChannels = 1;                    // 1 = Mono, 2 = Stereo
        m_waveFormat.wBitsPerSample = 16;               // Bits per sample per channel
        m_waveFormat.nSamplesPerSec = 48000;           // Sample Per Second
        m_waveFormat.nBlockAlign = m_waveFormat.nChannels * m_waveFormat.wBitsPerSample / 8;
        m_waveFormat.nAvgBytesPerSec = m_waveFormat.nSamplesPerSec * m_waveFormat.nBlockAlign;
        m_waveFormat.cbSize = 0;
    }

    void Play(AudioFrame* af)
    {
        // Create our "Sound is Done" event
        m_done = CreateEvent(0, FALSE, FALSE, 0);

        // Open the audio device
        if (waveOutOpen(&m_waveOut, 0, &m_waveFormat, (DWORD)m_done, 0, CALLBACK_EVENT) != MMSYSERR_NOERROR)
        {
            std::cout << "Sound card cannot be opened." << std::endl;
            return;
        }

        // Create the wave header for our sound buffer
        m_waveHeader.lpData = af->Data;
        m_waveHeader.dwBufferLength = af->DataSize;
        m_waveHeader.dwFlags = 0;
        m_waveHeader.dwLoops = 0;

        // Prepare the header for playback on sound card
        if (waveOutPrepareHeader(m_waveOut, &m_waveHeader, sizeof(m_waveHeader)) != MMSYSERR_NOERROR)
        {
            std::cout << "Error preparing Header!" << std::endl;
            return;
        }

        ResetEvent(m_done); // Reset our Event so it is non-signaled, it will be signaled again with buffer finished

        // Play the sound!
        if (waveOutWrite(m_waveOut, &m_waveHeader, sizeof(m_waveHeader)) != MMSYSERR_NOERROR)
        {
            std::cout << "Error writing to sound card!" << std::endl;
            return;
        }

        // Wait until sound finishes playing
        if (WaitForSingleObject(m_done, INFINITE) != WAIT_OBJECT_0)
        {
            std::cout << "Error waiting for sound to finish" << std::endl;
            return;
        }

        // Unprepare our wav header
        if (waveOutUnprepareHeader(m_waveOut, &m_waveHeader, sizeof(m_waveHeader)) != MMSYSERR_NOERROR)
        {
            std::cout << "Error unpreparing header!" << std::endl;
            return;
        }

        // Close the wav device
        if (waveOutClose(m_waveOut) != MMSYSERR_NOERROR)
        {
            std::cout << "Sound card cannot be closed!" << std::endl;
            return;
        }

        // Release our event handle
        CloseHandle(m_done);
    }



private:
    HWAVEOUT m_waveOut; // Handle to sound card output
    WAVEFORMATEX m_waveFormat; // The sound format
    WAVEHDR m_waveHeader; // WAVE header for our sound data
    HANDLE m_done; // Event Handle that tells us the sound has finished being played.
                   // This is a very efficient way to put the program to sleep
                   // while the sound card is processing the sound buffer

};

int main()
{
    FILE * fileDes;
    fopen_s(&fileDes, "Ducksauce.raw", "rb");
    if (fileDes == nullptr)
        std::cout << "File opening failed.\n";

    int bufferSize = FRAME_SIZE_IN_BYTES;
    char *buffer = new char[bufferSize];

    SoundPlayer sp;

    while (fread(buffer, sizeof(char), bufferSize, fileDes) > 0)
    {
        AudioFrame af;
        af.Data = buffer;
        af.DataSize = bufferSize;
        sp.Play(&af);
    }

    fclose(fileDes);
    delete[] buffer;
    return 0;
}

编辑：版本号 2。仍然无法按预期工作。

#include <windows.h>
#include <iostream>
#pragma comment(lib, "Winmm.lib")

constexpr int FRAME_SIZE_IN_BYTES = 1920;

struct AudioFrame
{
    char *Data;
    int DataSize;
};

class SoundPlayer
{
public:

    SoundPlayer()
    {
        // Initialize the sound format we will request from sound card
        m_waveFormat.wFormatTag = WAVE_FORMAT_PCM;     // Uncompressed sound format
        m_waveFormat.nChannels = 1;                    // 1 = Mono, 2 = Stereo
        m_waveFormat.wBitsPerSample = 16;               // Bits per sample per channel
        m_waveFormat.nSamplesPerSec = 48000;           // Sample Per Second
        m_waveFormat.nBlockAlign = m_waveFormat.nChannels * m_waveFormat.wBitsPerSample / 8;
        m_waveFormat.nAvgBytesPerSec = m_waveFormat.nSamplesPerSec * m_waveFormat.nBlockAlign;
        m_waveFormat.cbSize = 0;

        // Create our "Sound is Done" event
        m_done = CreateEvent(0, FALSE, FALSE, 0);

        // Open the audio device
        if (waveOutOpen(&m_waveOut, 0, &m_waveFormat, (DWORD)m_done, 0, CALLBACK_EVENT) != MMSYSERR_NOERROR)
        {
            std::cout << "Sound card cannot be opened." << std::endl;
            return;
        }
    }

    ~SoundPlayer()
    {
        // Close the wav device
        if (waveOutClose(m_waveOut) != MMSYSERR_NOERROR)
        {
            std::cout << "Sound card cannot be closed!" << std::endl;
            return;
        }

        // Release our event handle
        CloseHandle(m_done);
    }

    void StartPlaying(AudioFrame* af)
    {
        // Create the wave header for our sound buffer
        m_waveHeader.lpData = af->Data;
        m_waveHeader.dwBufferLength = af->DataSize;
        m_waveHeader.dwFlags = 0;
        m_waveHeader.dwLoops = 0;

        // Prepare the header for playback on sound card
        if (waveOutPrepareHeader(m_waveOut, &m_waveHeader, sizeof(m_waveHeader)) != MMSYSERR_NOERROR)
        {
            std::cout << "Error preparing Header!" << std::endl;
            return;
        }

        ResetEvent(m_done); // Reset our Event so it is non-signaled, it will be signaled again with buffer finished

        // Play the sound!
        if (waveOutWrite(m_waveOut, &m_waveHeader, sizeof(m_waveHeader)) != MMSYSERR_NOERROR)
        {
            std::cout << "Error writing to sound card!" << std::endl;
            return;
        }
    }

    void WaitUntilFrameFinishes()
    {
        // Wait until sound finishes playing
        if (WaitForSingleObject(m_done, INFINITE) != WAIT_OBJECT_0)
        {
            std::cout << "Error waiting for sound to finish" << std::endl;
            return;
        }
        // Unprepare our wav header
        if (waveOutUnprepareHeader(m_waveOut, &m_waveHeader, sizeof(m_waveHeader)) != MMSYSERR_NOERROR)
        {
            std::cout << "Error unpreparing header!" << std::endl;
            return;
        }
    }

private:
    HWAVEOUT m_waveOut; // Handle to sound card output
    WAVEFORMATEX m_waveFormat; // The sound format
    WAVEHDR m_waveHeader; // WAVE header for our sound data
    HANDLE m_done; // Event Handle that tells us the sound has finished being played.
                   // This is a very efficient way to put the program to sleep
                   // while the sound card is processing the sound buffer

};

int main()
{
    FILE * fileDes;
    fopen_s(&fileDes, "Ducksauce.raw", "rb");
    if (fileDes == nullptr)
        std::cout << "File opening failed.\n";

    int bufferSize = FRAME_SIZE_IN_BYTES;
    char *buffer = new char[bufferSize];

    SoundPlayer sp;

    // Read first time
    fread(buffer, sizeof(char), bufferSize, fileDes);

    while (true)
    {
        AudioFrame af;
        af.Data = buffer;
        af.DataSize = bufferSize;
        // Start playing, but don't block
        sp.StartPlaying(&af);
        // Prepare the next chunk
        if (fread(buffer, sizeof(char), bufferSize, fileDes) <= 0)
            break;
        // Now block the code, waiting with next chunk already loaded
        // and ready to be played in the next iteration.
        sp.WaitUntilFrameFinishes();
    }

    fclose(fileDes);
    delete[] buffer;
    return 0;
}

编辑2：如果我在while之前添加它，它会起作用：

for (int i = 0; i < 3; i++ )
{
    fread(buffer, sizeof(char), bufferSize, fileDes);
    af.Data = buffer;
    af.DataSize = bufferSize;
    sp.StartPlaying(&af);
}

我也稍微修改了一下：

while (true)
{
    // Prepare the next chunk
    if (fread(buffer, sizeof(char), bufferSize, fileDes) <= 0)
        break;
    // Now block the code, waiting with next chunk already loaded
    // and ready to be played in the next iteration.
    sp.WaitUntilFrameFinishes();

    af.Data = buffer;
    af.DataSize = bufferSize;
    sp.StartPlaying(&af);
}

Answer 1

您应该在播放声音时从磁盘读取数据，而不是在缓冲区之间！

如果您不能一次读取整个文件，您应该更改您的Play 函数，使其不只是调用WaitForSingleObject。使用它会使您的代码阻塞并等待声音停止播放。

你需要的是开始播放，然后回到你的阅读循环，准备下一个缓冲区，然后然后等待音乐结束，就像这样（SoundPlayer）：

void WaitUntilFrameFinishes() {
    // Wait until sound finishes playing
    if (WaitForSingleObject(m_done, INFINITE) != WAIT_OBJECT_0)

    // ... move all the code from Play till the end here
}

然后回到main循环：

// Read first frame
fread(buffer, sizeof(char), bufferSize, fileDes);

while (true)
{
    AudioFrame af;
    af.Data = buffer;
    af.DataSize = bufferSize;

    // Start playing, but don't block
    sp.Play(&af);

    // Prepare the next chunk
    if (fread(buffer, sizeof(char), bufferSize, fileDes) <= 0) {
        break;

    // Now block the code, waiting with next chunk already loaded
    // and ready to be played in the next iteration.
    sp.WaitUntilFrameFinishes();
}

理想情况下，您还可以将 fread 调用包装成可以以更好的方式提供块的东西。

Answer 2

在尝试仅根据文档弄清楚如何进行音频播放之后，我找到了this excellent tutorial。如果有人在尝试使用 Waveform 音频创建音频播放时发现此线程，这是一个非常好的参考点（肯定比我上面的错误代码好得多）。

关于我的代码，我怀疑它不能正常工作，因为应该使用waveOutWrite() 始终保持 AudioFrames 队列至少有几个帧，以防止声卡必须等待另一个 AudioFrame 的情况。