Kode Sampel Streaming Audio

2025-03-13

[Fitur yang terkait dengan halaman ini, DirectShow, adalah fitur warisan. Ini telah digantikan oleh MediaPlayer, IMFMediaEngine, dan Pengambilan Audio /Video di Media Foundation. Fitur-fitur tersebut telah dioptimalkan untuk Windows 10 dan Windows 11. Microsoft sangat menyarankan agar kode baru menggunakan MediaPlayer, IMFMediaEngine dan Pengambilan Audio/Video di Media Foundation alih-alih DirectShow, jika memungkinkan. Microsoft menyarankan agar kode yang ada yang menggunakan API warisan ditulis ulang untuk menggunakan API baru jika memungkinkan.]

Nota

API ini tidak digunakan lagi. Aplikasi harus menggunakan filter Sample Grabber atau menerapkan filter kustom untuk mendapatkan data dari grafik filter DirectShow.

Sampel kode berikut menunjukkan cara melakukan streaming data audio menggunakan IAudioMediaStream, IAudioStreamSample, IMemoryData, dan antarmukaIAudioData. Untuk brevity, contoh ini melakukan pemeriksaan kesalahan minimal.

#include <windows.h>
#include <stdio.h>
#include <mmsystem.h>
#include <amstream.h>

class CWaveBuffer {
    public:
        ~CWaveBuffer();
        BOOL Init(HWAVEOUT hWave, int Size);
        BOOL Write(PBYTE pData, int nBytes, int& BytesWritten);
        void Flush();
    private:
        WAVEHDR      m_Hdr;
        HWAVEOUT     m_hWave;
        int          m_nBytes;
};

class CWaveOut {
    public:
        CWaveOut(LPCWAVEFORMATEX Format, int nBuffers, int BufferSize);
        ~CWaveOut();
        void Write(PBYTE Data, int nBytes);
        void Flush();
        void Wait();
        void Reset();
    private:
        const HANDLE   m_hSem;
        const int      m_nBuffers;
        int            m_CurrentBuffer;
        BOOL           m_NoBuffer;
        CWaveBuffer   *m_Hdrs;
        HWAVEOUT       m_hWave;
};

BOOL CWaveBuffer::Init(HWAVEOUT hWave, int Size)
{
    m_hWave  = hWave;
    m_nBytes = 0;

    /*  Allocate a buffer and initialize the header. */
    m_Hdr.lpData = (LPSTR)LocalAlloc(LMEM_FIXED, Size);
    if (m_Hdr.lpData == NULL) 
    {
        return FALSE;
    }
    m_Hdr.dwBufferLength  = Size;
    m_Hdr.dwBytesRecorded = 0;
    m_Hdr.dwUser = 0;
    m_Hdr.dwFlags = 0;
    m_Hdr.dwLoops = 0;
    m_Hdr.lpNext = 0;
    m_Hdr.reserved = 0;

    /*  Prepare it. */
    waveOutPrepareHeader(hWave, &m_Hdr, sizeof(WAVEHDR));
    return TRUE;
}

CWaveBuffer::~CWaveBuffer() 
{
    if (m_Hdr.lpData) 
    {
        waveOutUnprepareHeader(m_hWave, &m_Hdr, sizeof(WAVEHDR));
        LocalFree(m_Hdr.lpData);
    }
}

void CWaveBuffer::Flush()
{
    // ASSERT(m_nBytes != 0);
    m_nBytes = 0;
    waveOutWrite(m_hWave, &m_Hdr, sizeof(WAVEHDR));
}

BOOL CWaveBuffer::Write(PBYTE pData, int nBytes, int& BytesWritten)
{
    // ASSERT((DWORD)m_nBytes != m_Hdr.dwBufferLength);
    BytesWritten = min((int)m_Hdr.dwBufferLength - m_nBytes, nBytes);
    CopyMemory((PVOID)(m_Hdr.lpData + m_nBytes), (PVOID)pData, BytesWritten);
    m_nBytes += BytesWritten;
    if (m_nBytes == (int)m_Hdr.dwBufferLength) 
    {
        /*  Write it! */
        m_nBytes = 0;
        waveOutWrite(m_hWave, &m_Hdr, sizeof(WAVEHDR));
        return TRUE;
    }
    return FALSE;
}

void CALLBACK WaveCallback(HWAVEOUT hWave, UINT uMsg, DWORD dwUser, 
                           DWORD dw1, DWORD dw2)
{
    if (uMsg == WOM_DONE) 
    {
        ReleaseSemaphore((HANDLE)dwUser, 1, NULL);
    }
}

CWaveOut::CWaveOut(LPCWAVEFORMATEX Format, int nBuffers, int BufferSize) :
    m_nBuffers(nBuffers),
    m_CurrentBuffer(0),
    m_NoBuffer(TRUE),
    m_hSem(CreateSemaphore(NULL, nBuffers, nBuffers, NULL)),
    m_Hdrs(new CWaveBuffer[nBuffers]),
    m_hWave(NULL)
{
    /*  Create wave device. */
    waveOutOpen(&m_hWave,
                WAVE_MAPPER,
                Format,
                (DWORD)WaveCallback,
                (DWORD)m_hSem,
                CALLBACK_FUNCTION);

    /*  Initialize the wave buffers. */
    for (int i = 0; i < nBuffers; i++) 
    {
        m_Hdrs[i].Init(m_hWave, BufferSize);
    }
}

CWaveOut::~CWaveOut()
{
    /*  First, get the buffers back. */
    waveOutReset(m_hWave);
    /*  Free the buffers. */
    delete [] m_Hdrs;
    /*  Close the wave device. */
    waveOutClose(m_hWave);
    /*  Free the semaphore. */
    CloseHandle(m_hSem);
}

void CWaveOut::Flush()
{
    if (!m_NoBuffer) 
    {
        m_Hdrs[m_CurrentBuffer].Flush();
        m_NoBuffer = TRUE;
        m_CurrentBuffer = (m_CurrentBuffer + 1) % m_nBuffers;
    }
}

void CWaveOut::Reset()
{
    waveOutReset(m_hWave);
}

void CWaveOut::Write(PBYTE pData, int nBytes)
{
    while (nBytes != 0) 
    {
        /*  Get a buffer if necessary. */
        if (m_NoBuffer) 
        {
            WaitForSingleObject(m_hSem, INFINITE);
            m_NoBuffer = FALSE;
        }

        /*  Write into a buffer. */
        int nWritten;
        if (m_Hdrs[m_CurrentBuffer].Write(pData, nBytes, nWritten)) 
        {
            m_NoBuffer = TRUE;
            m_CurrentBuffer = (m_CurrentBuffer + 1) % m_nBuffers;
            nBytes -= nWritten;
            pData += nWritten;
        } 
        else 
        {
            // ASSERT(nWritten == nBytes);
            break;
        }
    }
}

void CWaveOut::Wait()
{
    /*  Send any remaining buffers. */
    Flush();
    /*  Wait for the buffers back. */
    for (int i = 0; i < m_nBuffers; i++) 
    {
        WaitForSingleObject(m_hSem, INFINITE);
    }
    LONG lPrevCount;
    ReleaseSemaphore(m_hSem, m_nBuffers, &lPrevCount);
}

HRESULT RenderStreamToDevice(IMultiMediaStream *pMMStream)
{
    WAVEFORMATEX wfx;
    #define DATA_SIZE 5000

    IMediaStream        *pStream = NULL;
    IAudioStreamSample  *pSample = NULL;
    IAudioMediaStream   *pAudioStream = NULL;
    IAudioData          *pAudioData = NULL;

    HRESULT hr = pMMStream->GetMediaStream(MSPID_PrimaryAudio, &pStream);
    if (FAILED(hr))
    {
        return hr;
    }

    pStream->QueryInterface(IID_IAudioMediaStream, (void **)&pAudioStream);
    pStream->Release();

    hr = CoCreateInstance(CLSID_AMAudioData, NULL, 
        CLSCTX_INPROC_SERVER, IID_IAudioData, (void **)&pAudioData);
    if (FAILED(hr))
    {
        pAudioStream->Release();
        return hr;
    }

    PBYTE pBuffer = (PBYTE)LocalAlloc(LMEM_FIXED, DATA_SIZE);
    if (pBuffer == NULL)
    {
        pAudioStream->Release();
        pAudioData->Release();
        return E_OUTOFMEMORY;
    }

    pAudioStream->GetFormat(&wfx);
    pAudioData->SetBuffer(DATA_SIZE, pBuffer, 0);
    pAudioData->SetFormat(&wfx);
    hr = pAudioStream->CreateSample(pAudioData, 0, &pSample);
    pAudioStream->Release();
    if (FAILED(hr))
    {
        LocalFree((HLOCAL)pBuffer);
        pAudioData->Release();
        pSample->Release();
        return hr;
    }

    CWaveOut WaveOut(&wfx, 4, 2048);
    HANDLE hEvent = CreateEvent(FALSE, NULL, NULL, FALSE);
    if (hEvent != 0)
    {
        int iTimes;
        for (iTimes = 0; iTimes < 3; iTimes++) 
        {
            DWORD dwStart = timeGetTime();
            for (; ; ) 
            {
                hr = pSample->Update(0, hEvent, NULL, 0);
                if (FAILED(hr) || hr == MS_S_ENDOFSTREAM) 
                {
                    break;
                }
                WaitForSingleObject(hEvent, INFINITE);
                DWORD dwTimeDiff = timeGetTime() - dwStart;
                // Limit to 10 seconds
                if (dwTimeDiff > 10000) {
                    break;
                }
                DWORD dwLength;
                pAudioData->GetInfo(NULL, NULL, &dwLength);
                WaveOut.Write(pBuffer, dwLength);
            }
            pMMStream->Seek(0);
        }
    }

    pAudioData->Release();
    pSample->Release();
    LocalFree((HLOCAL)pBuffer);
    return S_OK;
}

HRESULT RenderFileToMMStream(
    const char * szFileName, 
    IMultiMediaStream **ppMMStream)
{
    if (strlen(szFileName) > MAX_PATH)
    {
        return E_INVALIDARG;
    }

    IAMMultiMediaStream *pAMStream;
    HRESULT hr = CoCreateInstance(CLSID_AMMultiMediaStream, NULL, 
        CLSCTX_INPROC_SERVER, IID_IAMMultiMediaStream, 
        (void **)&pAMStream);
    if (FAILED(hr))
    { 
        return hr;
    }

    WCHAR wszName[MAX_PATH + 1];
    MultiByteToWideChar(CP_ACP, 0, szFileName, -1, wszName,
        MAX_PATH + 1);
    
    pAMStream->Initialize(STREAMTYPE_READ, AMMSF_NOGRAPHTHREAD, NULL);
    pAMStream->AddMediaStream(NULL, &MSPID_PrimaryAudio, 0, NULL);
    hr = pAMStream->OpenFile(wszName, AMMSF_RUN);
    {
        if (SUCCEEDED(hr))
        {
            hr = pAMStream->QueryInterface(IID_IMultiMediaStream, 
                (void**)ppMMStream);
        }
    }
    pAMStream->Release();
    return hr;
}

int __cdecl main(int argc, char *argv[])
{
    if (argc < 2)
    {
        printf("Specify a file name.\n");
        exit(0);
    }

    IMultiMediaStream *pMMStream;
    CoInitialize(NULL);
    HRESULT hr = RenderFileToMMStream(argv[1], &pMMStream);
    if (SUCCEEDED(hr))
    {
        RenderStreamToDevice(pMMStream);
        pMMStream->Release();
    }
    
    CoUninitialize();
    return 0;
}

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