A Basic Media Player

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Introducting MCIWnd Window Class

MCIWnd is a window class for controlling multimedia devices. A library of functions, messages, and macros associated with MCIWnd provides a simple method to add multimedia playback or recording capabilities to your applications. 

The MCIWnd Window class is very easy to use. By identifying a simple HWND member variable and assigning it to MCI window using a single function, you can create a control that plays any device that uses the media control interface (MCI) and gain support of any installed codec on your machine. These devices include Audio CDs, WAV Audios, MIDIs, and video devices with any supported codec.

Automating playback is also quick and easy. Using only one function and two macros, an application can create an MCIWnd window with the appropriate media device, play the device, and close both the device and the window when the content has finished playing.

Note that term device refers to any playable media from file stored to any playable medium.

Note: to use MCIWnd Class in your application you must add vfw32.lib library to Link sections of Project Settings (accessible by Ctrl+F7) or simply add following line your header:

#pragma comment(lib, "vfw32.lib")

which does the same.

Considering we want to write a dialog based player, after adding library, add a HWND member variable to your dialog class (as mentioned above), for example:

HWND m_Player;

Then, add following code to any section you want to open your media for playing:

m_Player = MCIWndCreate(GetSafeHwnd(),AfxGetInstanceHandle(),
    WS_CHILD | WS_VISIBLE, m_sFileName);

Where m_sFileName is a member variable which holds media name. After that you can use single line macros to control media playback. e.g. MCIWndPlay(m_Player) to start media playback or MCIWndStop(m_Player).

You are done, you have a media player now!

A wrapper class for MCIWnd: CEasyPlayer 

I have written a very simple wrapper class for this API. This wrapper class is part of my work. That certain program needed simple playback of wav and mp3 media and sometimes continuous playing (loop). So, I just wrapped very few macros and messages in implementing the class. The class interface is as below:

class CEasyPlayer : public CWnd
{
public:
CEasyPlayer();
CEasyPlayer(HWND hwParent);

public:
HWND hwndParent;

public:
long lPos;
void Rwd();
void Fwd();
void DecreaseVolume();
void IncreaseVolume();
long GetVolume();
long lVolume;
void SetVolume(long lVol);
long GetLength();
long GetPosition();
void SetPosition(long lPos);
HWND GetWindowHandle();
void Resume();
void Kill();
void Break();
void Loop();
void Close();
HWND Initialize();
void Play();
void Stop();
void Pause();
long GetMode();
CString GetPath();
void SetPath(CString sPath);
void SetParent(HWND hParent);
HWND GetParent();
virtual ~CEasyPlayer();

protected:
HWND c_Player;
CEvent m_Event;
CString m_sPath;

//{{AFX_MSG(CEasyPlayer)
afx_msg void OnDestroy();
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
};

c_Player is that so called HWND member variable. I use c_ prefix to determine control variables from other member variables(Values). Initialize() creates MCIWnd control and assigns it to c_Player. Other functions are identify themselves by their names which show exact duty of function. It is necessary to mention that GetMode() is used to determine playback status and returns one of following values:

Class code is clear, it just wraps some macros, passes values to them and gets results from them. The only part of code that may need description is Loop() function. Using Loop() will cause launching a thread call to LoopThread() which implementation is as follows:

UINT LoopThread(LPVOID pParam)
{
    CParams* pParameters;
    pParameters=(CParams*)pParam;

    CEasyPlayer* pWnd=(CEasyPlayer*)pParameters->pWnd;
    CEvent* pEvent=(CEvent*)pParameters->pEvent;
    HWND c_Player=(HWND)pParameters->hWnd;

    while(WaitForSingleObject(pEvent->m_hObject,5)==WAIT_TIMEOUT)
    {
        if (pWnd->GetMode()==MCI_MODE_STOP)
            ::PostMessage(c_Player, MCI_PLAY, 0, 0);
    }
    return 0;
}

A conditional loop which checks if m_Event member variable of class is set, if not then checks if media playback stoped. If so then replys the media by sending a MCI_PLAY message to HWND control. Very simple!

Media Player

After concluding that project, I decided to try writing a Media Player, and that'is it. Using potentials of CStatic control as a CWnd derived class, I made a GUI for my wrapper class. I used a CStatic control to hold onto video media playback (if exist). This CStatic control rules as CEasyPlayer instance parent.

Changing approach this application did not used Loop() member function for continuous media playback. Instead a timer used to periodically check if media stopped or not.

I must mention that I used Nishant S approach to handles key board messages and menu accelerators in this application. Thank you very much Nishant S.