播放光盘轨道
以下示例打开 CD 音频设备,播放 bTrack 参数指定的曲目,并在播放完成后关闭设备。 它使用 mciSendCommand 函数。
// Plays a specified audio track using MCI_OPEN, MCI_PLAY. Returns as
// soon as playback begins. The window procedure function for the
// specified window will be notified when playback is complete.
// Returns 0L on success; otherwise, returns an MCI error code.
DWORD playCDTrack(HWND hWndNotify, BYTE bTrack)
{
UINT wDeviceID;
DWORD dwReturn;
MCI_OPEN_PARMS mciOpenParms;
MCI_SET_PARMS mciSetParms;
MCI_PLAY_PARMS mciPlayParms;
// Open the CD audio device by specifying the device name.
mciOpenParms.lpstrDeviceType = "cdaudio";
if (dwReturn = mciSendCommand(NULL, MCI_OPEN,
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;
// Set the time format to track/minute/second/frame (TMSF).
mciSetParms.dwTimeFormat = MCI_FORMAT_TMSF;
if (dwReturn = mciSendCommand(wDeviceID, MCI_SET,
MCI_SET_TIME_FORMAT, (DWORD)(LPVOID) &mciSetParms))
{
mciSendCommand(wDeviceID, MCI_CLOSE, 0, NULL);
return (dwReturn);
}
// Begin play from the specified track and play to the beginning
// of the next track. The window procedure function for the parent
// window will be notified with an MM_MCINOTIFY message when
// playback is complete. Unless the play command fails, the window
// procedure closes the device.
mciPlayParms.dwFrom = 0L;
mciPlayParms.dwTo = 0L;
mciPlayParms.dwFrom = MCI_MAKE_TMSF(bTrack, 0, 0, 0);
mciPlayParms.dwTo = MCI_MAKE_TMSF(bTrack + 1, 0, 0, 0);
mciPlayParms.dwCallback = (DWORD) hWndNotify;
if (dwReturn = mciSendCommand(wDeviceID, MCI_PLAY,
MCI_FROM | MCI_TO | MCI_NOTIFY,
(DWORD)(LPVOID) &mciPlayParms))
{
mciSendCommand(wDeviceID, MCI_CLOSE, 0, NULL);
return (dwReturn);
}
return (0L);
}
若要指定相对于光盘上轨道的位置,必须使用曲目/分钟/秒/帧 (TMSF) 时间格式。