Recording with a Waveform-Audio Device

[The feature associated with this page, MCI, is a legacy feature. It has been superseded by MediaPlayer. MediaPlayer has been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer instead of MCI, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The following example opens a waveform-audio device with a new file, records for the specified time, plays the recording, and prompts the user to save the recording if desired. It uses the mciSendCommand function.

// 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);
}