注：写了一系列分析Media Player Classic - HC 源代码的文章，在此列一个列表：

上一篇文章分析了Media Player Classic - HC（mpc-hc）的源代码中的核心类 CMainFrame：

主要介绍了CMainFrame类中的以下几个函数（“->”代表调用关系）：

OpenMedia()->OpenMediaPrivate()->OpenFile()

本文补充介绍CMainFrame类中的其他一些函数。

再回顾一下打开文件功能主要所在的函数OpenMediaPrivate()：

//打开一个媒体（private）bool CMainFrame::OpenMediaPrivate(CAutoPtr
    
      pOMD){	//获得设置信息    CAppSettings& s = AfxGetAppSettings();    if (m_iMediaLoadState != MLS_CLOSED) {        ASSERT(0);        return false;    }	//OpenFileData	//OpenDVDData	//OpenDeviceData	//里面包含了文件或者DVD信息（名称等）    OpenFileData* pFileData = dynamic_cast
     
      (pOMD.m_p);    OpenDVDData* pDVDData = dynamic_cast
      
       (pOMD.m_p);    OpenDeviceData* pDeviceData = dynamic_cast
       
        (pOMD.m_p);    if (!pFileData && !pDVDData  && !pDeviceData) {        ASSERT(0);        return false;    }    // Clear DXVA state ...    ClearDXVAState();#ifdef _DEBUG    // Debug trace code - Begin    // Check for bad / buggy auto loading file code    if (pFileData) {        POSITION pos = pFileData->fns.GetHeadPosition();        UINT index = 0;        while (pos != nullptr) {            CString path = pFileData->fns.GetNext(pos);            TRACE(_T("--> CMainFrame::OpenMediaPrivate - pFileData->fns[%d]:\n"), index);            TRACE(_T("\t%ws\n"), path.GetString()); // %ws - wide character string always            index++;        }    }    // Debug trace code - End#endif    CString mi_fn = _T("");    if (pFileData) {        if (pFileData->fns.IsEmpty()) {            return false;        }        CString fn = pFileData->fns.GetHead();        int i = fn.Find(_T(":\\"));        if (i > 0) {            CString drive = fn.Left(i + 2);            UINT type = GetDriveType(drive);            CAtlList
        
          sl;            if (type == DRIVE_REMOVABLE || type == DRIVE_CDROM && GetCDROMType(drive[0], sl) != CDROM_Audio) {                int ret = IDRETRY;                while (ret == IDRETRY) {                    WIN32_FIND_DATA findFileData;                    HANDLE h = FindFirstFile(fn, &findFileData);                    if (h != INVALID_HANDLE_VALUE) {                        FindClose(h);                        ret = IDOK;                    } else {                        CString msg;                        msg.Format(IDS_MAINFRM_114, fn);                        ret = AfxMessageBox(msg, MB_RETRYCANCEL);                    }                }                if (ret != IDOK) {                    return false;                }            }            mi_fn = fn;        }    }    SetLoadState(MLS_LOADING);    // FIXME: Don't show "Closed" initially    PostMessage(WM_KICKIDLE);    CString err;    m_fUpdateInfoBar = false;    BeginWaitCursor();    try {        CComPtr
         
              pVMB;        CComPtr
          
            pMFVMB;        CComPtr
           
                   pMVTO;        if (m_fOpeningAborted) {            throw (UINT)IDS_AG_ABORTED;        }        OpenCreateGraphObject(pOMD);        if (m_fOpeningAborted) {            throw (UINT)IDS_AG_ABORTED;        }        SetupIViAudReg();        if (m_fOpeningAborted) {            throw (UINT)IDS_AG_ABORTED;        } //按类型的不同打开不同的文件        if (pFileData) { //文件            OpenFile(pFileData);        } else if (pDVDData) { //DVD            OpenDVD(pDVDData);        } else if (pDeviceData) {            if (s.iDefaultCaptureDevice == 1) {                HRESULT hr = OpenBDAGraph();                if (FAILED(hr)) {                    throw (UINT)IDS_CAPTURE_ERROR_DEVICE;                }            } else {                OpenCapture(pDeviceData);            }        } else {            throw (UINT)IDS_INVALID_PARAMS_ERROR;        }        m_pCAP2 = nullptr;        m_pCAP = nullptr; //查找接口        m_pGB->FindInterface(__uuidof(ISubPicAllocatorPresenter), (void**)&m_pCAP, TRUE);        m_pGB->FindInterface(__uuidof(ISubPicAllocatorPresenter2), (void**)&m_pCAP2, TRUE);        m_pGB->FindInterface(__uuidof(IVMRWindowlessControl9), (void**)&m_pVMRWC, FALSE); // might have IVMRMixerBitmap9, but not IVMRWindowlessControl9        m_pGB->FindInterface(__uuidof(IVMRMixerControl9), (void**)&m_pVMRMC, TRUE);        m_pGB->FindInterface(__uuidof(IVMRMixerBitmap9), (void**)&pVMB, TRUE);        m_pGB->FindInterface(__uuidof(IMFVideoMixerBitmap), (void**)&pMFVMB, TRUE);        pMVTO = m_pCAP;        if (s.fShowOSD || s.fShowDebugInfo) { // Force OSD on when the debug switch is used            if (pVMB) {                m_OSD.Start(m_pVideoWnd, pVMB, IsD3DFullScreenMode());            } else if (pMFVMB) {                m_OSD.Start(m_pVideoWnd, pMFVMB, IsD3DFullScreenMode());            } else if (pMVTO) {                m_OSD.Start(m_pVideoWnd, pMVTO);            }        } //VMR9        SetupVMR9ColorControl();        // === EVR !        m_pGB->FindInterface(__uuidof(IMFVideoDisplayControl), (void**)&m_pMFVDC,  TRUE);        m_pGB->FindInterface(__uuidof(IMFVideoProcessor), (void**)&m_pMFVP, TRUE);        if (m_pMFVDC) {            m_pMFVDC->SetVideoWindow(m_pVideoWnd->m_hWnd);        }        //SetupEVRColorControl();        //does not work at this location        //need to choose the correct mode (IMFVideoProcessor::SetVideoProcessorMode)        BeginEnumFilters(m_pGB, pEF, pBF) {            if (m_pLN21 = pBF) {                m_pLN21->SetServiceState(s.fClosedCaptions ? AM_L21_CCSTATE_On : AM_L21_CCSTATE_Off);                break;            }        }        EndEnumFilters;        if (m_fOpeningAborted) {            throw (UINT)IDS_AG_ABORTED;        } //打开自定义的Graph        OpenCustomizeGraph();        if (m_fOpeningAborted) {            throw (UINT)IDS_AG_ABORTED;        } //设置视频窗口        OpenSetupVideo();        if (m_fOpeningAborted) {            throw (UINT)IDS_AG_ABORTED;        } //设置音量        OpenSetupAudio();        if (m_fOpeningAborted) {            throw (UINT)IDS_AG_ABORTED;        }        if (m_pCAP && (!m_fAudioOnly || m_fRealMediaGraph)) {            if (s.fDisableInternalSubtitles) {                m_pSubStreams.RemoveAll(); // Needs to be replaced with code that checks for forced subtitles.            }            m_posFirstExtSub = nullptr;            POSITION pos = pOMD->subs.GetHeadPosition();            while (pos) {                LoadSubtitle(pOMD->subs.GetNext(pos), nullptr, true);            }        }        if (m_fOpeningAborted) {            throw (UINT)IDS_AG_ABORTED;        } //设置视频窗口标题        OpenSetupWindowTitle(pOMD->title);        if (s.fEnableEDLEditor) {            m_wndEditListEditor.OpenFile(pOMD->title);        }        if (::GetCurrentThreadId() == AfxGetApp()->m_nThreadID) {            OnFilePostOpenmedia();        } else {            PostMessage(WM_COMMAND, ID_FILE_POST_OPENMEDIA);        }        while (m_iMediaLoadState != MLS_LOADED                && m_iMediaLoadState != MLS_CLOSING // FIXME              ) {            Sleep(50);        } //设置音频流        DWORD audstm = SetupAudioStreams(); //设置字幕流        DWORD substm = SetupSubtitleStreams();        if (audstm) {            OnPlayAudio(ID_AUDIO_SUBITEM_START + audstm);        }        if (substm) {            SetSubtitle(substm - 1);        }        // PostMessage instead of SendMessage because the user might call CloseMedia and then we would deadlock        PostMessage(WM_COMMAND, ID_PLAY_PAUSE);        m_bFirstPlay = true;        if (!(s.nCLSwitches & CLSW_OPEN) && (s.nLoops > 0)) {            PostMessage(WM_COMMAND, ID_PLAY_PLAY);        } else {            // If we don't start playing immediately, we need to initialize            // the seekbar and the time counter.            OnTimer(TIMER_STREAMPOSPOLLER);            OnTimer(TIMER_STREAMPOSPOLLER2);        }        s.nCLSwitches &= ~CLSW_OPEN;        if (pFileData) {            if (pFileData->rtStart > 0) {                PostMessage(WM_RESUMEFROMSTATE, (WPARAM)PM_FILE, (LPARAM)(pFileData->rtStart / 10000));  // REFERENCE_TIME doesn't fit in LPARAM under a 32bit env.            }        } else if (pDVDData) {            if (pDVDData->pDvdState) {                PostMessage(WM_RESUMEFROMSTATE, (WPARAM)PM_DVD, (LPARAM)(CComPtr
            
             (pDVDData->pDvdState).Detach()));    // must be released by the called message handler            }        } else if (pDeviceData) {            m_wndCaptureBar.m_capdlg.SetVideoInput(pDeviceData->vinput);            m_wndCaptureBar.m_capdlg.SetVideoChannel(pDeviceData->vchannel);            m_wndCaptureBar.m_capdlg.SetAudioInput(pDeviceData->ainput);        }    } catch (LPCTSTR msg) {        err = msg;    } catch (CString& msg) {        err = msg;    } catch (UINT msg) {        err.LoadString(msg);    }    EndWaitCursor();    if (!err.IsEmpty()) { //关闭        CloseMediaPrivate();        m_closingmsg = err;        if (err != ResStr(IDS_AG_ABORTED)) {            if (pFileData) {                m_wndPlaylistBar.SetCurValid(false);                if (m_wndPlaylistBar.IsAtEnd()) {                    m_nLoops++;                }                if (s.fLoopForever || m_nLoops < s.nLoops) {                    bool hasValidFile = false;                    if (m_nLastSkipDirection == ID_NAVIGATE_SKIPBACK) {                        hasValidFile = m_wndPlaylistBar.SetPrev();                    } else {                        hasValidFile = m_wndPlaylistBar.SetNext();                    }                    if (hasValidFile) {                        OpenCurPlaylistItem();                    }                } else if (m_wndPlaylistBar.GetCount() > 1) {                    DoAfterPlaybackEvent();                }            } else {                OnNavigateSkip(ID_NAVIGATE_SKIPFORWARD);            }        }    } else {        m_wndPlaylistBar.SetCurValid(true);        // Apply command line audio shift        if (s.rtShift != 0) {            SetAudioDelay(s.rtShift);            s.rtShift = 0;        }    }    m_nLastSkipDirection = 0;    if (s.AutoChangeFullscrRes.bEnabled && (m_fFullScreen || IsD3DFullScreenMode())) {        AutoChangeMonitorMode();    }    if (m_fFullScreen && s.fRememberZoomLevel) {        m_fFirstFSAfterLaunchOnFS = true;    }    m_LastOpenFile = pOMD->title;    PostMessage(WM_KICKIDLE); // calls main thread to update things    if (!m_bIsBDPlay) {        m_MPLSPlaylist.RemoveAll();        m_LastOpenBDPath = _T("");    }    m_bIsBDPlay = false;    return err.IsEmpty();}
            
           
          
         
        
       
      
     
    

来看一看OpenMediaPrivate()函数的细节：

1.开始的时候有这么一句

CAppSettings& s = AfxGetAppSettings();

在这里涉及到一个类CAppSettings，存储的是mpc-hc用到的各种设置信息。源代码如下：

//应用程序中的各种参数class CAppSettings{    bool fInitialized;    class CRecentFileAndURLList : public CRecentFileList    {    public:        CRecentFileAndURLList(UINT nStart, LPCTSTR lpszSection,                              LPCTSTR lpszEntryFormat, int nSize,                              int nMaxDispLen = AFX_ABBREV_FILENAME_LEN);        virtual void Add(LPCTSTR lpszPathName); // we have to override CRecentFileList::Add because the original version can't handle URLs    };public:    bool fShaderEditorWasOpened;    // cmdline params    UINT nCLSwitches;    CAtlList
    
        slFiles, slDubs, slSubs, slFilters;    // Initial position (used by command line flags)    REFERENCE_TIME      rtShift;    REFERENCE_TIME      rtStart;    ULONG               lDVDTitle;    ULONG               lDVDChapter;    DVD_HMSF_TIMECODE   DVDPosition;    CSize sizeFixedWindow;    bool HasFixedWindowSize() const { return sizeFixedWindow.cx > 0 || sizeFixedWindow.cy > 0; }    //int           iFixedWidth, iFixedHeight;    int             iMonitor;    CString         ParseFileName(CString const& param);    void            ParseCommandLine(CAtlList
     
      & cmdln);    // Added a Debug display to the screen (/debug option)    bool            fShowDebugInfo;    int             iAdminOption;    //播放器 Player    bool            fAllowMultipleInst;    bool            fTrayIcon;    bool            fShowOSD;    bool            fLimitWindowProportions;    bool            fSnapToDesktopEdges;    bool            fHideCDROMsSubMenu;    DWORD           dwPriority;    int             iTitleBarTextStyle;    bool            fTitleBarTextTitle;    bool            fKeepHistory;    CRecentFileAndURLList MRU;    CRecentFileAndURLList MRUDub;    CFilePositionList filePositions;    CDVDPositionList  dvdPositions;    bool            fRememberDVDPos;    bool            fRememberFilePos;    bool            bRememberPlaylistItems;    bool            fRememberWindowPos;    CRect           rcLastWindowPos;    bool            fRememberWindowSize;    bool            fSavePnSZoom;    double          dZoomX;    double          dZoomY;    // Formats    CMediaFormats   m_Formats;    bool            fAssociatedWithIcons;    // Keys    CList
      
           wmcmds;    HACCEL          hAccel;    bool            fWinLirc;    CString         strWinLircAddr;    CWinLircClient  WinLircClient;    bool            fUIce;    CString         strUIceAddr;    CUIceClient     UIceClient;    bool            fGlobalMedia;    //图标 Logo    UINT            nLogoId;    bool            fLogoExternal;    CString         strLogoFileName;    //web界面？ Web Inteface    BOOL            fEnableWebServer;    int             nWebServerPort;    int             nCmdlnWebServerPort;    bool            fWebServerUseCompression;    bool            fWebServerLocalhostOnly;    bool            fWebServerPrintDebugInfo;    CString         strWebRoot, strWebDefIndex;    CString         strWebServerCGI;    //播放时候 Playback    int             nVolume;    bool            fMute;    int             nBalance;    int             nLoops;    bool            fLoopForever;    bool            fRewind;    bool            fRememberZoomLevel;    int             nAutoFitFactor;    int             iZoomLevel;    CStringW        strAudiosLanguageOrder;    CStringW        strSubtitlesLanguageOrder;    bool            fEnableWorkerThreadForOpening;    bool            fReportFailedPins;    bool            fAutoloadAudio;    bool            fAutoloadSubtitles;    bool            fBlockVSFilter;    UINT            nVolumeStep;    UINT            nSpeedStep;    // DVD/OGM    bool            fUseDVDPath;    CString         strDVDPath;    LCID            idMenuLang, idAudioLang, idSubtitlesLang;    bool            fAutoSpeakerConf;    bool            fClosedCaptions;    //输出 Output    CRenderersSettings m_RenderersSettings;    int             iDSVideoRendererType;    int             iRMVideoRendererType;    int             iQTVideoRendererType;    CStringW        strAudioRendererDisplayName;    bool            fD3DFullscreen;    //全屏 Fullscreen    bool            fLaunchfullscreen;    bool            fShowBarsWhenFullScreen;    int             nShowBarsWhenFullScreenTimeOut;    bool            fExitFullScreenAtTheEnd;    CStringW        strFullScreenMonitor;    AChFR           AutoChangeFullscrRes;    bool            fRestoreResAfterExit;    // Sync Renderer Settings    // Capture (BDA configuration)    int             iDefaultCaptureDevice;      // Default capture device (analog=0, 1=digital)    CString         strAnalogVideo;    CString         strAnalogAudio;    int             iAnalogCountry;    CString         strBDANetworkProvider;    CString         strBDATuner;    CString         strBDAReceiver;    //CString           strBDAStandard;    int             iBDAScanFreqStart;    int             iBDAScanFreqEnd;    int             iBDABandwidth;    bool            fBDAUseOffset;    int             iBDAOffset;    bool            fBDAIgnoreEncryptedChannels;    UINT            nDVBLastChannel;    CAtlList
       
         m_DVBChannels;    DVB_RebuildFilterGraph nDVBRebuildFilterGraph;    DVB_StopFilterGraph nDVBStopFilterGraph;    // Internal Filters    bool            SrcFilters[SRC_LAST + !SRC_LAST];    bool            TraFilters[TRA_LAST + !TRA_LAST];    //音频 Audio Switcher    bool            fEnableAudioSwitcher;    bool            fAudioNormalize;    UINT            nAudioMaxNormFactor;    bool            fAudioNormalizeRecover;    UINT            nAudioBoost;    bool            fDownSampleTo441;    bool            fAudioTimeShift;    int             iAudioTimeShift;    bool            fCustomChannelMapping;    int             nSpeakerChannels;    DWORD           pSpeakerToChannelMap[AS_MAX_CHANNELS][AS_MAX_CHANNELS];    // External Filters    CAutoPtrList
        
          m_filters;    //字幕 Subtitles    bool            fOverridePlacement;    int             nHorPos, nVerPos;    int             nSubDelayInterval;    // Default Style    STSStyle        subdefstyle;    // Misc    bool            bPreferDefaultForcedSubtitles;    bool            fPrioritizeExternalSubtitles;    bool            fDisableInternalSubtitles;    bool            bAllowOverridingExternalSplitterChoice;    CString         strSubtitlePaths;    CString         strISDb;    // Tweaks    int             nJumpDistS;    int             nJumpDistM;    int             nJumpDistL;    bool            fFastSeek;    bool            fShowChapters;    bool            bNotifySkype;    bool            fPreventMinimize;    bool            fUseWin7TaskBar;    bool            fLCDSupport;    bool            fUseSearchInFolder;    bool            fUseTimeTooltip;    int             nTimeTooltipPosition;    CString         strOSDFont;    int             nOSDSize;    //亮度色度饱和度 Miscellaneous    int             iBrightness;    int             iContrast;    int             iHue;    int             iSaturation;    int             nUpdaterAutoCheck;    int             nUpdaterDelay;    // MENUS    // View    int             iCaptionMenuMode; // normal -> hidemenu -> frameonly -> borderless    bool            fHideNavigation;    UINT            nCS; // Control state for toolbars    // Language    LANGID          language;    // Subtitles menu    bool            fEnableSubtitles;    bool            fUseDefaultSubtitlesStyle;    // Video Frame    int             iDefaultVideoSize;    bool            fKeepAspectRatio;    CSize           sizeAspectRatio;    bool            fCompMonDeskARDiff;    // Pan&Scan    CString         strPnSPreset;    CStringArray    m_pnspresets;    // On top menu    int             iOnTop;    // After Playback    bool            fExitAfterPlayback;    bool            fNextInDirAfterPlayback;    // WINDOWS    // Add Favorite    bool            bFavRememberPos;    bool            bFavRelativeDrive;    // Save Image...    CString         strSnapShotPath, strSnapShotExt;    // Save Thumbnails...    int             iThumbRows, iThumbCols, iThumbWidth;    // Shader Editor    struct Shader {        CString     label;        CString     target;        CString     srcdata;    };    CAtlList
         
           m_shaders;    // Shader Combiner    bool            fToggleShader;    bool            fToggleShaderScreenSpace;    CString         strShaderList;    CString         strShaderListScreenSpace;    // Playlist (contex menu)    bool            bShufflePlaylistItems;    bool            bHidePlaylistFullScreen;    // OTHER STATES    CStringW        strLastOpenDir;    UINT            nLastWindowType;    UINT            nLastUsedPage;    bool            fRemainingTime;    bool            fLastFullScreen;    bool            fIntRealMedia;    //bool          fRealMediaRenderless;    //float         dRealMediaQuickTimeFPS;    //int           iVideoRendererType;    //int           iQuickTimeRenderer;    //bool          fMonitorAutoRefreshRate;    bool            fEnableEDLEditor;    HWND            hMasterWnd;    bool            IsD3DFullscreen() const;    CString         SelectedAudioRenderer() const;    bool            IsISREnabled() const;private:    CString         SrcFiltersKeys[SRC_LAST + !SRC_LAST];    CString         TraFiltersKeys[TRA_LAST + !TRA_LAST];    __int64         ConvertTimeToMSec(const CString& time) const;    void            ExtractDVDStartPos(CString& strParam);    void            CreateCommands();    void            SaveExternalFilters(CAutoPtrList
          
           & filters, LPCTSTR baseKey = IDS_R_EXTERNAL_FILTERS);    void            LoadExternalFilters(CAutoPtrList
           
            & filters, LPCTSTR baseKey = IDS_R_EXTERNAL_FILTERS);    void            ConvertOldExternalFiltersList();    void            UpdateRenderersData(bool fSave);    friend void     CRenderersSettings::UpdateData(bool bSave);public:    CAppSettings();    virtual ~CAppSettings();    void            SaveSettings();    void            LoadSettings();    void            SaveExternalFilters() { if (fInitialized) { SaveExternalFilters(m_filters); } };    void            GetFav(favtype ft, CAtlList
            
             & sl) const;    void            SetFav(favtype ft, CAtlList
             
              & sl);    void            AddFav(favtype ft, CString s);    CDVBChannel*    FindChannelByPref(int nPrefNumber);    bool            GetAllowMultiInst() const;    static bool     IsVSFilterInstalled();    static bool     HasEVR();};
             
            
           
          
         
        
       
      
     
    

由代码可见，包含的参数信息很多。在mpc-hc中，任何需要获取设置信息的地方，都可以使用AfxGetAppSettings()获得CAppSettings的引用。

2.OpenSetupVideo()这个函数的作用是设置视频窗口，源代码如下：

//设置视频窗口void CMainFrame::OpenSetupVideo(){	//大部分都在确定：m_fAudioOnly是否为True    m_fAudioOnly = true;	//获得视频的宽和高，然后调整窗口大小    if (m_pMFVDC) { // EVR        m_fAudioOnly = false;    } else if (m_pCAP) {        CSize vs = m_pCAP->GetVideoSize();        m_fAudioOnly = (vs.cx <= 0 || vs.cy <= 0);    } else {        {            long w = 0, h = 0;            if (CComQIPtr
    
      pBV = m_pGB) {                pBV->GetVideoSize(&w, &h);            }            if (w > 0 && h > 0) {                m_fAudioOnly = false;            }        }		//如果 m_fAudioOnly=true；再检查        if (m_fAudioOnly) {            BeginEnumFilters(m_pGB, pEF, pBF) {                long w = 0, h = 0;                if (CComQIPtr
     
       pVW = pBF) {                    long lVisible;                    if (FAILED(pVW->get_Visible(&lVisible))) {                        continue;                    }                    pVW->get_Width(&w);                    pVW->get_Height(&h);                }                if (w > 0 && h > 0) {                    m_fAudioOnly = false;                    break;                }            }            EndEnumFilters;        }    }    if (m_fShockwaveGraph) {        m_fAudioOnly = false;    }    if (m_pCAP) {        SetShaders();    }    // else    {        // TESTME		//设置所有者。。。        m_pVW->put_Owner((OAHWND)m_pVideoWnd->m_hWnd);        m_pVW->put_WindowStyle(WS_CHILD | WS_CLIPSIBLINGS | WS_CLIPCHILDREN);        m_pVW->put_MessageDrain((OAHWND)m_hWnd);        for (CWnd* pWnd = m_wndView.GetWindow(GW_CHILD); pWnd; pWnd = pWnd->GetNextWindow()) {            pWnd->EnableWindow(FALSE);    // little trick to let WM_SETCURSOR thru        }    }	//如果只有音频，则消灭视频窗口！    if (m_fAudioOnly && IsD3DFullScreenMode()) {        m_pFullscreenWnd->DestroyWindow();    }}
     
    

3. OpenSetupAudio()这个函数的作用是设置音频，源代码如下：

//设置音量void CMainFrame::OpenSetupAudio(){	//设置音量    m_pBA->put_Volume(m_wndToolBar.Volume);    // FIXME    int balance = AfxGetAppSettings().nBalance;    int sign = balance > 0 ? -1 : 1; // -1: invert sign for more right channel    if (balance > -100 && balance < 100) {        balance = sign * (int)(100 * 20 * log10(1 - abs(balance) / 100.0f));    } else {        balance = sign * (-10000);  // -10000: only left, 10000: only right    }	//设置均衡    m_pBA->put_Balance(balance);}

4.如果出现问题，则会调用CloseMediaPrivate()，关闭打开的媒体。

//关闭void CMainFrame::CloseMediaPrivate(){    SetLoadState(MLS_CLOSING); // why it before OnPlayStop()? // TODO: remake or add detailed comments    OnPlayStop(); // SendMessage(WM_COMMAND, ID_PLAY_STOP);    if (m_pMC) {        m_pMC->Stop(); // needed for StreamBufferSource, because m_iMediaLoadState is always MLS_CLOSED // TODO: fix the opening for such media    }    SetPlaybackMode(PM_NONE);    m_fLiveWM = false;    m_fEndOfStream = false;    m_rtDurationOverride = -1;    m_kfs.RemoveAll();    m_pCB.Release();    {        CAutoLock cAutoLock(&m_csSubLock);        m_pSubStreams.RemoveAll();    }    m_pSubClock.Release();    //if (m_pVW) m_pVW->put_Visible(OAFALSE);    //if (m_pVW) m_pVW->put_MessageDrain((OAHWND)NULL), m_pVW->put_Owner((OAHWND)NULL);    // IMPORTANT: IVMRSurfaceAllocatorNotify/IVMRSurfaceAllocatorNotify9 has to be released before the VMR/VMR9, otherwise it will crash in Release()    //各种清空	m_OSD.Stop();    m_pCAP2.Release();    m_pCAP.Release();    m_pVMRWC.Release();    m_pVMRMC.Release();    m_pMFVP.Release();    m_pMFVDC.Release();    m_pLN21.Release();    m_pSyncClock.Release();    m_pAMXBar.Release();    m_pAMDF.Release();    m_pAMVCCap.Release();    m_pAMVCPrev.Release();    m_pAMVSCCap.Release();    m_pAMVSCPrev.Release();    m_pAMASC.Release();    m_pVidCap.Release();    m_pAudCap.Release();    m_pAMTuner.Release();    m_pCGB.Release();    m_pDVDC.Release();    m_pDVDI.Release();    m_pAMOP.Release();    m_pBI.Release();    m_pQP.Release();    m_pFS.Release();    m_pMS.Release();    m_pBA.Release();    m_pBV.Release();    m_pVW.Release();    m_pME.Release();    m_pMC.Release();    if (m_pGB) {        m_pGB->RemoveFromROT();        m_pGB.Release();    }    m_pProv.Release();    m_fRealMediaGraph = m_fShockwaveGraph = m_fQuicktimeGraph = false;    m_VidDispName.Empty();    m_AudDispName.Empty();    m_closingmsg.LoadString(IDS_CONTROLS_CLOSED);    AfxGetAppSettings().nCLSwitches &= CLSW_OPEN | CLSW_PLAY | CLSW_AFTERPLAYBACK_MASK | CLSW_NOFOCUS;	//设置状态    SetLoadState(MLS_CLOSED);}