Grabación con un dispositivo Waveform-Audio

[La característica asociada a esta página, MCI, es una característica heredada. Se ha reemplazado por MediaPlayer. MediaPlayer se ha optimizado para Windows 10 y Windows 11. Microsoft recomienda encarecidamente que el nuevo código use MediaPlayer en lugar de MCI, siempre que sea posible. Microsoft sugiere que el código existente que usa las API heredadas se reescriba para usar las nuevas API si es posible.

En el ejemplo siguiente se abre un dispositivo de audio de forma de onda con un nuevo archivo, registros para el tiempo especificado, reproduce la grabación y solicita al usuario que guarde la grabación si lo desea. Usa la función mciSendCommand.

// Uses the MCI_OPEN, MCI_RECORD, and MCI_SAVE commands to record and
// save a waveform-audio file. Returns 0L if successful; otherwise,
// it returns an MCI error code.

DWORD recordWAVEFile(DWORD dwMilliSeconds)
{
    UINT wDeviceID;
    DWORD dwReturn;
    MCI_OPEN_PARMS mciOpenParms;
    MCI_RECORD_PARMS mciRecordParms;
    MCI_SAVE_PARMS mciSaveParms;
    MCI_PLAY_PARMS mciPlayParms;

    // Open a waveform-audio device with a new file for recording.
    mciOpenParms.lpstrDeviceType = "waveaudio";
    mciOpenParms.lpstrElementName = "";
    if (dwReturn = mciSendCommand(0, MCI_OPEN,
        MCI_OPEN_ELEMENT | MCI_OPEN_TYPE, 
        (DWORD)(LPVOID) &mciOpenParms))
    {
        // Failed to open device; don't close it, just return error.
        return (dwReturn);
    }

    // The device opened successfully; get the device ID.
    wDeviceID = mciOpenParms.wDeviceID;

    // Begin recording and record for the specified number of 
    // milliseconds. Wait for recording to complete before continuing. 
    // Assume the default time format for the waveform-audio device 
    // (milliseconds).
    mciRecordParms.dwTo = dwMilliSeconds;
    if (dwReturn = mciSendCommand(wDeviceID, MCI_RECORD, 
        MCI_TO | MCI_WAIT, (DWORD)(LPVOID) &mciRecordParms))
    {
        mciSendCommand(wDeviceID, MCI_CLOSE, 0, NULL);
        return (dwReturn);
    }

    // Play the recording and query user to save the file.
    mciPlayParms.dwFrom = 0L;
    if (dwReturn = mciSendCommand(wDeviceID, MCI_PLAY,
        MCI_FROM | MCI_WAIT, (DWORD)(LPVOID) &mciPlayParms))
    {
        mciSendCommand(wDeviceID, MCI_CLOSE, 0, NULL);
        return (dwReturn);
    }
    if (MessageBox(hMainWnd, "Do you want to save this recording?",
        "", MB_YESNO) == IDNO)
    {
        mciSendCommand(wDeviceID, MCI_CLOSE, 0, NULL);
        return (0L);
    }

    // Save the recording to a file named TEMPFILE.WAV. Wait for
    // the operation to complete before continuing.
    mciSaveParms.lpfilename = "tempfile.wav";
    if (dwReturn = mciSendCommand(wDeviceID, MCI_SAVE,
        MCI_SAVE_FILE | MCI_WAIT, (DWORD)(LPVOID) &mciSaveParms))
    {
        mciSendCommand(wDeviceID, MCI_CLOSE, 0, NULL);
        return (dwReturn);
    }

    return (0L);
}