wince下用DirectShow播放音频和视频

1、wince下用DirectShow播放音频和视频wince下用DirectShow播放音频和视频         虽然网上关于wince下如何使用DirectShow播放多媒体文件的资料不多,但WinCE毕竟还属于windows,而桌面系统的DirectShow例子网上信手拈来,并且其中DirectShow的功能方法与之WinCE下差别不大,又本人实在没有信心比他们的轮子造得更为华丽,所以这篇文章就直接切入正题,不介绍DirectShow的结构功能,直接来看看怎么用吧.(其实还是自己懒惰的原因大一些,恩,不过这个和本文的主题

2、没多大关系:-).               为了方便代码的移植,所以我将DirectShow的操作封装成CMedia类,只要直接调用该类,就可以相当简便地调用DirectShow来播放多媒体文件了                好,闲话至此,我们以具体代码看看是如何:     

3、;    /获取CMedia的实例        CMedia *m_pMedia = CMedia:GetInstance();                /设置播放的窗口        m_pMedia->SetVideoWindow(hWnd);  &#

4、160;             /打开媒体文件        m_pMedia->Open(TEXT("A.AVI");                /播放        m_pM

5、edia->Play();                .                /播放结束后,调用Close释放资源        m_pMedia->Open();     

6、   没错,就是六行代码,就这么简单,可以顺利播放媒体文件.在这里要说一下的是,因为我们播放的是视频,需要有一个窗口显示,所以需要调用SetVideoWindow()函数来设置播放窗口.这个播放视频的窗口,可以是普通的窗口,也可以是Picture控件.当然咯,如果是播放音频文件,那么则完全可以无视这个函数.                还有一个最值得注意的地方,当调用Open()成功之后,一定要调用Close()来释放资源,然后才能打

7、开另一个媒体文件.否则,不释放的资源可能会导致很多莫名其妙的后果哦.                        等等,代码似乎还不完美,比如说,我想在文件播放之后再接着播放另外一个文件,那么我如何知道什么时候文件已经播放完毕了呢?这时候我们就需要请出SetNotifyWindow().        &#

8、160;       该函数的作用是设置一个接受消息的窗口,当DirectShow有事件变更时,就会发送指定的消息到指定的窗口,原型如下:                SetNotifyWindow(HWND hWnd, UINT wMsg,long lInstanceData)          

9、0;     hWnd:接收消息的窗口句柄.                wMsg:指定的自定义消息                lInstanceData:消息的参数.         

10、0;              那么,现在以接收一个视频播放结束事件的代码片段为例子:         /自定义一个消息        #define WM_GRAPHNOTIFY        (WM_USER + 13)   

11、             /设置接收消息窗口和消息        m_pMedia->SetVideoWindow(hWnd,WM_GRAPHNOTIFY,NULL);                .      

12、          /这个是消息循环函数        LRESULT CMainWnd:WndProc(HWND hWnd, UINT wMsg, WPARAM wParam, LPARAM lParam)        .            switch(wMs

13、g)            .                            .            

14、0;               case WM_GRAPHNOTIFY:                .                 

15、;   LONG evCode,evParam1,evParam2;                                        /获取此时的DirectShow事件 &#

16、160;                  if(m_pMedia->GetEvent(&evCode,&evParam1,&evParam2) = TRUE)                    .

17、0;                       if(evCode = EC_COMPLETE)                        .&

18、#160;                           MessageBox(NULL,TEXT("播放完毕"),TEXT(""),MB_OK);            &

19、#160;                                                   retu

20、rn 0;                                                    .&#

21、160;                                   好了,知道播放完毕,就这么简单.恩,还很复杂.?呵呵,我觉得已经很简单了.            &#

22、160;   文章的最后,让我们再来看看CMedia的其它几个有用的函数吧:                CheckVisibility()        描述:判断文件的种类        当返回值为TRUE时,为视频文件;反之为只是音频文件.    &#

23、160;                   SetVolume(LONG lVolume, LONG lBalance)        描述:设置音量.        lVolume:设置音量的大小,范围为10,000 到 0.      

24、;  lBalance:设置左右音量的均衡,范围是10,000 到 10,000,默认是0.                        SetDisplayMode(DISPLAYMODE mode)        描述:设置播放模式.      

25、;  DISP_FIT:按比例拉伸至视屏窗口.        DISP_STRETCH:不按比例拉伸至视屏窗口.        DISP_NATIVE:如果视频原本尺寸小于屏幕,则以原视频文件大小播放.否则,将和DISP_FIT相同        DISP_FULLSCREEN:全屏/*/        /M

26、edia.h: interface for the CMedia class./Version:/    1.2.0/Date:/    2007.05.08/*/#ifndef MEDIA_H#define    MEDIA_H#include <mmsystem.h>#include <streams.h>/-/Macro define/The volume value#define MAX_VOLUME      &

27、#160;             0#define MIN_VOLUME                    -10000/The balance value#define MAX_BALANCE       

28、60;            10000#define MIN_BALANCE                    -10000/-/Enum valueenum DISPLAYMODE.        /Fit to the play

29、window size. How wide (height) the window is, how     /is the move. Keep aspect ratio.    DISP_FIT,    /Stretch to the play window size. Don't keep the aspect ratio.    DISP_STRETCH,    /Full screen play.   

30、; DISP_FULLSCREEN,    /When the size of video is smaller than the play window, it displayes    /as the video size. If it's bigger , it just like the DISP_FIT mode.    DISP_NATIVE;/-/The media file propertytypedef struct.    /The volume

31、range is 10,000 to 0.    /Divide by 100 to get equivalent decibel value (for example 10,000 = 100 dB).     LONG lVolume;    /The value from 10,000 to 10,000 indicating the stereo balance    /As with the Volume property, units correspond to

32、.01 decibels (multiplied by 1 when plBalance is a positive value).    /For example, a value of 1000 indicates 10 dB on the right channel and 90 dB on the left channel.     LONG lBalance;    /Width of the video      LONG lWidth; &#

33、160;  /Height of the video    LONG lHeight;    /Approximate bit rate    LONG lBitRate;MEDIAPROPERTY,*PMEDIAPROPERTY;/-class CMedia  .public:    BOOL GetEvent(LONG *plEvCode, LONG *plParam1, LONG *plParam2);    BOOL

34、SetNotifyWindow(HWND hWnd, UINT wMsg,long lInstanceData);    BOOL SetVolume(LONG lVolume, LONG lBalance = 0);    BOOL SetDisplayMode(DISPLAYMODE mode);    BOOL GetMediaProperty(PMEDIAPROPERTY pOutProperty);    static CMedia * GetInstance();

35、    void Close();    BOOL CheckVisibility();    void SetVideoWindow(HWND hWndVideo);    BOOL Open(TCHAR * pszFileName);    BOOL Stop();    BOOL Pause();    BOOL Play();    virtual

36、CMedia();protected:    CMedia();        / Collection of interfaces    IGraphBuilder *m_pGB;    IMediaControl *m_pMC;    IMediaEventEx *m_pME;    IVideoWindow  *m_pVW;    IBasi

37、cAudio   *m_pBA;    IBasicVideo   *m_pBV;    IMediaSeeking *m_pMS;    TCHAR m_szFileNameMAX_PATH;    HWND m_hWndVideo; /The window play video    HWND m_hWndNotify; /The window notify    BOOL

38、 m_bExitThrd;    BOOL m_bThrdRunning;    static CMedia * m_pInstance;    DISPLAYMODE m_DispMode;#endif /#ifndef MEDIA_H  /*/ Media.cpp: implementation of the CMedia class./*/#include "stdafx.h"#include "Media.h"/-/Macro defin

39、e/Default play mode#define DEFAULT_DISPLAY_MODE        DISP_NATIVE/-/InitializeCMedia *CMedia:m_pInstance = NULL;/-/*/ Construction/Destruction/*/CMedia:CMedia():m_pGB(NULL),m_pMC(NULL),m_pME(NULL),m_pVW(NULL),m_pBA(NULL),m_pBV(NULL),m_pMS(NULL),m_hWndVideo(NULL),m

40、_bExitThrd(TRUE),m_bThrdRunning(FALSE),m_DispMode(DEFAULT_DISPLAY_MODE),m_hWndNotify(NULL).    memset(m_szFileName,0,sizeof(m_szFileName);CMedia:CMedia().    if(m_pInstance != NULL)    .        delete m_pInstance; &

41、#160;      m_pInstance = NULL;     /-/Description:/    Play the media file/    When you call the function,you should call Open() before./-BOOL CMedia:Play().        / Run the graph to play the me

42、dia file    if(m_pMC = NULL)    .        return FALSE;                m_pMC->Run();    return TRUE; /-/Description:/    Pause. /

43、0;   When you call the function,you should call Open() before./-BOOL CMedia:Pause().    if(m_pMC = NULL)    .        return FALSE;            m_pMC->Pause();    r

44、eturn TRUE; /-/Description:/    Stop./    When you call the function,you should call Open() before./-BOOL CMedia:Stop().    if(m_pMC = NULL | m_pMS = NULL)    .        return FALSE;   

45、        m_pMC->Stop();        m_pMS->SetPositions(0, AM_SEEKING_AbsolutePositioning,NULL,AM_SEEKING_NoPositioning);           return TRUE; /-/Description:/    Open the media

46、file. When succeed in calling the function ,/you should call the Close() to release the resource/-BOOL CMedia:Open(TCHAR *pszFileName).    BOOL bResult = FALSE;        if(_tcslen(pszFileName) >= MAX_PATH)    .    

47、0;   goto END;        else    .        _tcscpy(m_szFileName,pszFileName);        /Check the file existing        HANDLE hdFile = CreateFile(

48、m_szFileName,GENERIC_READ,FILE_SHARE_READ,NULL,OPEN_EXISTING,NULL,NULL);        if(hdFile = INVALID_HANDLE_VALUE)        .            /The file doesn't exist  &#

49、160;         goto END;                else        .            CloseHandle(hdFile);   

50、;                  / Initialize COM     if(CoInitializeEx(NULL, COINIT_MULTITHREADED) != S_OK)    .        goto END;        / Get the i

51、nterface for DirectShow's GraphBuilder    if(CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, IID_IGraphBuilder, (void *)&m_pGB) != S_OK)    .        goto END;        / Have the grap

52、h construct its the appropriate graph automatically    if(m_pGB->RenderFile(m_szFileName, NULL) != NOERROR)    .        goto END;            / QueryInterface for DirectShow interfaces

53、0;   if(m_pGB->QueryInterface(IID_IMediaControl, (void *)&m_pMC) != NOERROR)    .        goto END;        if(m_pGB->QueryInterface(IID_IMediaEventEx, (void *)&m_pME) != NOERROR)   

54、.        goto END;        if(m_pGB->QueryInterface(IID_IMediaSeeking, (void *)&m_pMS) != NOERROR)    .        goto END;            /

55、Query for video interfaces, which may not be relevant for audio files    if(m_pGB->QueryInterface(IID_IVideoWindow, (void *)&m_pVW) != NOERROR)    .        goto END;        if(m_pGB->QueryInterfa

56、ce(IID_IBasicVideo, (void *)&m_pBV) != NOERROR)    .        goto END;            / Query for audio interfaces, which may not be relevant for video-only files    if(m_pGB->QueryInterfa

57、ce(IID_IBasicAudio, (void *)&m_pBA) != NOERROR)    .        goto END;            / Is this an audio-only file (no video component)?    if (CheckVisibility() = TRUE)    .&#

58、160;       if(m_pVW->put_Owner(OAHWND)m_hWndVideo) != NOERROR)        .            goto END;                

59、;    if(m_pVW->put_WindowStyle(WS_CHILD | WS_CLIPSIBLINGS | WS_CLIPCHILDREN) != NOERROR)        .            goto END;              

60、      /Set play mode    SetDisplayMode(m_DispMode);            bResult = TRUE;END:        if(bResult = FALSE)    .        /Release the resou

61、rce        Close();        return bResult; /-/Description:/    This method sets an owning parent for the video window. /Parameters:/    hWnd : in Handle of new owner window. /-void CMedia:SetVideoWind

62、ow(HWND hWndVideo).    m_hWndVideo = hWndVideo; /-/Description:/    Check the file visibility/    When you call the function,you should call Open() before./Parameters:/    TRUE: Video/    FALSE: It's not the video /-

63、BOOL CMedia:CheckVisibility().            if (!m_pVW)    .        /No VideoWindow interface.  Assuming audio/MIDI file or unsupported video codec        return FALSE

64、;            if (!m_pBV)    .        /No BasicVideo interface.  Assuming audio/MIDI file or unsupported video codec.        return FALSE;     

65、60;          / If this is an audio-only clip, get_Visible() won't work.    /    / Also, if this video is encoded with an unsupported codec,    / we won't see any video, although the audio will work if it is 

66、   / of a supported format.    long lVisible;    if(m_pVW->get_Visible(&lVisible) != NOERROR)    .        return FALSE;                return T

67、RUE; /-/Description:/    Release the resource which opened in the Open()    /-void CMedia:Close().    / Relinquish ownership (IMPORTANT!) after hiding    if(m_pVW)    .        m_pVW->

68、;put_Visible(OAFALSE);        m_pVW->put_Owner(NULL);        if(m_pMC != NULL)    .        m_pMC->Release();        m_pMC = NULL;  

69、60;     if(m_pME != NULL)    .        m_pME->SetNotifyWindow(NULL,NULL,NULL);        m_pME->Release();        m_pME = NULL;       

70、; if(m_pMS != NULL)    .        m_pMS->Release();        m_pMS = NULL;        if(m_pBV != NULL)    .        m_pBV->Release();

71、0;       m_pBV = NULL;            if(m_pBA != NULL)    .        m_pBA->Release();        m_pBA = NULL;      

72、0;     if(m_pVW != NULL)    .        m_pVW->Release();        m_pVW = NULL;        if(m_pGB != NULL)    .        m_pG

73、B->Release();        m_pGB = NULL;        / Finished with COM    memset(m_szFileName,0,sizeof(m_szFileName);    CoUninitialize();/-/Description:/    Get the instance of object/-CMedia * C

74、Media:GetInstance().    if(m_pInstance = NULL)    .        m_pInstance = new CMedia();        return m_pInstance; /-/Description:/    Get the media file property./    Whe

75、n you call the function,you should call Open() before./-BOOL CMedia:GetMediaProperty(PMEDIAPROPERTY pOutProperty).    MEDIAPROPERTY prop = .0;    if(m_pBA = NULL | m_pBV = NULL)    .        return FALSE;   

76、;     /Get the audio property    m_pBA->get_Volume(&prop.lVolume);    m_pBA->get_Balance(&prop.lBalance);    /Get the video property    if(CheckVisibility() = TRUE)    .    

77、60;   m_pBV->get_BitRate(&prop.lBitRate);        m_pBV->GetVideoSize(&prop.lWidth,&prop.lHeight);        *pOutProperty = prop;    return TRUE;/-/Description:/    Set the display

78、 mode./    When you call the function,you should call Open() before./-BOOL CMedia:SetDisplayMode(DISPLAYMODE mode).    if(m_pVW = NULL)    .        return FALSE;        m_DispMode = mode;

79、60;   if(mode = DISP_FULLSCREEN)    .        m_pVW->put_FullScreenMode(OATRUE);        else    .        /Restore to the normal mode    &#

80、160;   m_pVW->put_FullScreenMode(OAFALSE);                RECT rcWnd = .0;        GetClientRect(m_hWndVideo,&rcWnd);        LONG lWndWidth = rc

81、Wnd.right - rcWnd.left;        LONG lWndHeight = rcWnd.bottom - rcWnd.top;        MEDIAPROPERTY prop = .0;        GetMediaProperty(&prop);        if(mode =

82、DISP_FIT | mode = DISP_NATIVE)        .            LONG lDispLeft,lDispTop,lDispWidth,lDispHeight;            if(mode = DISP_NATIVE && lWndWidth &g

83、t;= prop.lWidth && lWndHeight >= prop.lHeight)            .                lDispLeft = (lWndWidth - prop.lWidth) / 2;       

84、         lDispTop = (lWndHeight - prop.lHeight) / 2;                lDispWidth = prop.lWidth;                l

85、DispHeight = prop.lHeight;                        else            .           &#

86、160;    if(prop.lWidth * lWndHeight > lWndWidth * prop.lHeight)                .                    lDispWidth =

87、 lWndWidth;                                    lDispHeight = (LONG)(float)lDispWidth / (float)prop.lWidth * prop.lHeight); &#

88、160;                  lDispLeft = 0;                    lDispTop = (lWndHeight - lDispHeight) / 2;   

89、0;                                    else if(prop.lWidth * lWndHeight < lWndWidth * prop.lHeight)     

90、0;          .                    lDispHeight = lWndHeight;                 

91、   lDispWidth = (LONG)(float)lDispHeight / (float)prop.lHeight * prop.lWidth);                    lDispLeft = (lWndWidth - lDispWidth) / 2;         &#

92、160;          lDispTop = 0;                                else       

93、         .                    lDispWidth = lWndWidth;                   

94、60;                lDispHeight = lWndHeight;                    lDispLeft = 0;                    lDispTop = 0;   &#