class CRendererInputPin : public CBaseInputPin
{
protected:

    CBaseRenderer *m_pRenderer;

public:

    CRendererInputPin(CBaseRenderer *pRenderer,
                      HRESULT *phr,
                      LPCWSTR Name);

    // Overriden from the base pin classes

    HRESULT BreakConnect();
    HRESULT CompleteConnect(IPin *pReceivePin);
    HRESULT SetMediaType(const CMediaType *pmt);
    HRESULT CheckMediaType(const CMediaType *pmt);
    HRESULT Active();
    HRESULT Inactive();

    // Add rendering behaviour to interface functions

    STDMETHODIMP QueryId(LPWSTR *Id);
    STDMETHODIMP EndOfStream();
    STDMETHODIMP BeginFlush();
    STDMETHODIMP EndFlush();
    STDMETHODIMP Receive(IMediaSample *pMediaSample);

    // Helper
    IMemAllocator inline *Allocator() const
    {
        return m_pAllocator;
    }
};

// Main renderer class that handles synchronisation and state changes

CBaseRenderer</h4>

---

  class CBaseRenderer : public CBaseFilter
  {
  protected:
  
      friend

---

CRendererInputPin;</h4>

---

   class CRendererInputPin;
  
      friend void CALLBACK EndOfStreamTimer(UINT uID,      // Timer identifier
                                            UINT uMsg,     // Not currently used
                                            DWORD_PTR dwUser,  // User information
                                            DWORD_PTR dw1,     // Windows reserved
                                            DWORD_PTR dw2);    // Is also reserved
  
      CRendererPosPassThru *m_pPosition;  // Media seeking pass by object
      CAMEvent m_RenderEvent;             // Used to signal timer events
      CAMEvent m_ThreadSignal;            // Signalled to release worker thread
      CAMEvent m_evComplete;              // Signalled when state complete
      BOOL m_bAbort;                      // Stop us from rendering more data
      BOOL m_bStreaming;                  // Are we currently streaming
      DWORD_PTR m_dwAdvise;                   // Timer advise cookie
      IMediaSample *m_pMediaSample;       // Current image media sample
      BOOL m_bEOS;                        // Any more samples in the stream
      BOOL m_bEOSDelivered;               // Have we delivered an EC_COMPLETE
      CRendererInputPin *m_pInputPin;     // Our renderer input pin object
      CCritSec m_InterfaceLock;           // Critical section for interfaces
      CCritSec m_RendererLock;            // Controls access to internals
      IQualityControl * m_pQSink;         // QualityControl sink
      BOOL m_bRepaintStatus;              // Can we signal an EC_REPAINT
      //  Avoid some deadlocks by tracking filter during stop
      volatile BOOL  m_bInReceive;        // Inside Receive between PrepareReceive
                                          // And actually processing the sample
      REFERENCE_TIME m_SignalTime;        // Time when we signal EC_COMPLETE
      UINT m_EndOfStreamTimer;            // Used to signal end of stream
      CCritSec m_ObjectCreationLock;      // This lock protects the creation and
                                          // of m_pPosition and m_pInputPin.  It
                                          // ensures that two threads cannot create
                                          // either object simultaneously.
  
  public:
  
      CBaseRenderer(REFCLSID RenderClass, // CLSID for this renderer
                    TCHAR *pName,         // Debug ONLY description
                    LPUNKNOWN pUnk,       // Aggregated owner object
                    HRESULT *phr);        // General OLE return code
  
      ~CBaseRenderer();
  
      // Overriden to say what interfaces we support and where
  
      virtual HRESULT GetMediaPositionInterface(REFIID riid,void **ppv);
      STDMETHODIMP NonDelegatingQueryInterface(REFIID, void **);
  
      virtual HRESULT SourceThreadCanWait(BOOL bCanWait);
  
  ifdef DEBUG
      // Debug only dump of the renderer state
      void DisplayRendererState();
  endif
      virtual HRESULT WaitForRenderTime();
      virtual HRESULT CompleteStateChange(FILTER_STATE OldState);
  
      // Return internal information about this filter
  
      BOOL IsEndOfStream() { return m_bEOS; };

---

      BOOL IsEndOfStreamDelivered() { return m_bEOSDelivered; };

---

      BOOL IsStreaming() { return m_bStreaming; };

---

      void SetAbortSignal(BOOL bAbort) { m_bAbort = bAbort; };

---

      virtual void OnReceiveFirstSample(IMediaSample *pMediaSample) { };

---

      CAMEvent *GetRenderEvent() { return &m_RenderEvent; };

---

  
      // Permit access to the transition state
  
      void Ready() { m_evComplete.Set(); };

---

      void NotReady() { m_evComplete.Reset(); };

---

      BOOL CheckReady() { return m_evComplete.Check(); };

---

  
      virtual int GetPinCount();
      virtual CBasePin *GetPin(int n);
      FILTER_STATE GetRealState();
      void SendRepaint();
      void SendNotifyWindow(IPin *pPin,HWND hwnd);
      BOOL OnDisplayChange();
      void SetRepaintStatus(BOOL bRepaint);
  
      // Override the filter and pin interface functions
  
      STDMETHODIMP Stop();
      STDMETHODIMP Pause();
      STDMETHODIMP Run(REFERENCE_TIME StartTime);
      STDMETHODIMP GetState(DWORD dwMSecs,FILTER_STATE *State);
      STDMETHODIMP FindPin(LPCWSTR Id, IPin **ppPin);
  
      // These are available for a quality management implementation
  
      virtual void OnRenderStart(IMediaSample *pMediaSample);
      virtual void OnRenderEnd(IMediaSample *pMediaSample);
      virtual HRESULT OnStartStreaming() { return NOERROR; };

---

      virtual HRESULT OnStopStreaming() { return NOERROR; };

---

      virtual void OnWaitStart() { };

---

      virtual void OnWaitEnd() { };

---

      virtual void PrepareRender() { };

---

  
  ifdef PERF
      REFERENCE_TIME m_trRenderStart; // Just before we started drawing
                                      // Set in OnRenderStart, Used in OnRenderEnd
      int m_idBaseStamp;              // MSR_id for frame time stamp
      int m_idBaseRenderTime;         // MSR_id for true wait time
      int m_idBaseAccuracy;           // MSR_id for time frame is late (int)
  endif
  
      // Quality management implementation for scheduling rendering
  
      virtual BOOL ScheduleSample(IMediaSample *pMediaSample);
      virtual HRESULT GetSampleTimes(IMediaSample *pMediaSample,
                                     REFERENCE_TIME *pStartTime,
                                     REFERENCE_TIME *pEndTime);
  
      virtual HRESULT ShouldDrawSampleNow(IMediaSample *pMediaSample,
                                          REFERENCE_TIME *ptrStart,
                                          REFERENCE_TIME *ptrEnd);
  
      // Lots of end of stream complexities
  
      void TimerCallback();
      void ResetEndOfStreamTimer();
      HRESULT NotifyEndOfStream();
      virtual HRESULT SendEndOfStream();
      virtual HRESULT ResetEndOfStream();
      virtual HRESULT EndOfStream();
  
      // Rendering is based around the clock
  
      void SignalTimerFired();
      virtual HRESULT CancelNotification();
      virtual HRESULT ClearPendingSample();
  
      // Called when the filter changes state
  
      virtual HRESULT Active();
      virtual HRESULT Inactive();
      virtual HRESULT StartStreaming();
      virtual HRESULT StopStreaming();
      virtual HRESULT BeginFlush();
      virtual HRESULT EndFlush();
  
      // Deal with connections and type changes
  
      virtual HRESULT BreakConnect();
      virtual HRESULT SetMediaType(const CMediaType *pmt);
      virtual HRESULT CompleteConnect(IPin *pReceivePin);
  
      // These look after the handling of data samples
  
      virtual HRESULT PrepareReceive(IMediaSample *pMediaSample);
      virtual HRESULT Receive(IMediaSample *pMediaSample);
      virtual BOOL HaveCurrentSample();
      virtual IMediaSample *GetCurrentSample();
      virtual HRESULT Render(IMediaSample *pMediaSample);
  
      // Derived classes MUST override these
      virtual HRESULT DoRenderSample(IMediaSample *pMediaSample) PURE;
      virtual HRESULT CheckMediaType(const CMediaType *) PURE;
  
      // Helper
      void WaitForReceiveToComplete();
  };

---

  
  // CBaseVideoRenderer is a renderer class (see its ancestor class) and
  // it handles scheduling of media samples so that they are drawn at the
  // correct time by the reference clock.  It implements a degradation
  // strategy.  Possible degradation modes are:
  //    Drop frames here (only useful if the drawing takes significant time)
  //    Signal supplier (upstream) to drop some frame(s) - i.e. one-off skip.
  //    Signal supplier to change the frame rate - i.e. ongoing skipping.
  //    Or any combination of the above.
  // In order to determine what's useful to try we need to know what's going
  // on.  This is done by timing various operations (including the supplier).
  // This timing is done by using timeGetTime as it is accurate enough and
  // usually cheaper than calling the reference clock.  It also tells the
  // truth if there is an audio break and the reference clock stops.
  // We provide a number of public entry points (named OnXxxStart, OnXxxEnd)
  // which the rest of the renderer calls at significant moments.  These do
  // the timing.
  
  // the number of frames that the sliding averages are averaged over.
  // the rule is (1024*NewObservation + (AVGPERIOD-1) * PreviousAverage)/AVGPERIOD
  define AVGPERIOD 4
  define DO_MOVING_AVG(avg,obs) (avg = (1024*obs + (AVGPERIOD-1)*avg)/AVGPERIOD)
  // Spot the bug in this macro - I can't. but it doesn't work!
  
  

---

CBaseVideoRenderer</h4>

---

  class CBaseVideoRenderer : public CBaseRenderer,    // Base renderer class
                             public IQualProp,        // Property page guff
                             public IQualityControl   // Allow throttling
  {
  protected:
  
      // Hungarian:
      //     tFoo is the time Foo in mSec (beware m_tStart from filter.h)
      //     trBar is the time Bar by the reference clock
  
      //******************************************************************
      // State variables to control synchronisation
      //******************************************************************
  
      // Control of sending Quality messages.  We need to know whether
      // we are in trouble (e.g. frames being dropped) and where the time
      // is being spent.
  
      // When we drop a frame we play the next one early.
      // The frame after that is likely to wait before drawing and counting this
      // wait as spare time is unfair, so we count it as a zero wait.
      // We therefore need to know whether we are playing frames early or not.
  
      int m_nNormal;                  // The number of consecutive frames
                                      // drawn at their normal time (not early)
                                      // -1 means we just dropped a frame.
  
  ifdef PERF
      BOOL m_bDrawLateFrames;         // Don't drop any frames (debug and I'm
                                      // not keen on people using it!)
  endif
  
      BOOL m_bSupplierHandlingQuality;// The response to Quality messages says
                                      // our supplier is handling things.
                                      // We will allow things to go extra late
                                      // before dropping frames.  We will play
                                      // very early after he has dropped one.
  
      // Control of scheduling, frame dropping etc.
      // We need to know where the time is being spent so as to tell whether
      // we should be taking action here, signalling supplier or what.
      // The variables are initialised to a mode of NOT dropping frames.
      // They will tell the truth after a few frames.
      // We typically record a start time for an event, later we get the time
      // again and subtract to get the elapsed time, and we average this over
      // a few frames.  The average is used to tell what mode we are in.
  
      // Although these are reference times (64 bit) they are all DIFFERENCES
      // between times which are small.  An int will go up to 214 secs before
      // overflow.  Avoiding 64 bit multiplications and divisions seems
      // worth while.
  
      // Audio-video throttling.  If the user has turned up audio quality
      // very high (in principle it could be any other stream, not just audio)
      // then we can receive cries for help via the graph manager.  In this case
      // we put in a wait for some time after rendering each frame.
      int m_trThrottle;
  
      // The time taken to render (i.e. BitBlt) frames controls which component
      // needs to degrade.  If the blt is expensive, the renderer degrades.
      // If the blt is cheap it's done anyway and the supplier degrades.
      int m_trRenderAvg;              // Time frames are taking to blt
      int m_trRenderLast;             // Time for last frame blt
      int m_tRenderStart;             // Just before we started drawing (mSec)
                                      // derived from timeGetTime.
  
      // When frames are dropped we will play the next frame as early as we can.
      // If it was a false alarm and the machine is fast we slide gently back to
      // normal timing.  To do this, we record the offset showing just how early
      // we really are.  This will normally be negative meaning early or zero.
      int m_trEarliness;
  
      // Target provides slow long-term feedback to try to reduce the
      // average sync offset to zero.  Whenever a frame is actually rendered
      // early we add a msec or two, whenever late we take off a few.
      // We add or take off 1/32 of the error time.
      // Eventually we should be hovering around zero.  For a really bad case
      // where we were (say) 300mSec off, it might take 100 odd frames to
      // settle down.  The rate of change of this is intended to be slower
      // than any other mechanism in Quartz, thereby avoiding hunting.
      int m_trTarget;
  
      // The proportion of time spent waiting for the right moment to blt
      // controls whether we bother to drop a frame or whether we reckon that
      // we're doing well enough that we can stand a one-frame glitch.
      int m_trWaitAvg;                // Average of last few wait times
                                      // (actually we just average how early
                                      // we were).  Negative here means LATE.
  
      // The average inter-frame time.
      // This is used to calculate the proportion of the time used by the
      // three operations (supplying us, waiting, rendering)
      int m_trFrameAvg;               // Average inter-frame time
      int m_trDuration;               // duration of last frame.
  
  ifdef PERF
      // Performance logging identifiers
      int m_idTimeStamp;              // MSR_id for frame time stamp
      int m_idEarliness;              // MSR_id for earliness fudge
      int m_idTarget;                 // MSR_id for Target fudge
      int m_idWaitReal;               // MSR_id for true wait time
      int m_idWait;                   // MSR_id for wait time recorded
      int m_idFrameAccuracy;          // MSR_id for time frame is late (int)
      int m_idRenderAvg;              // MSR_id for Render time recorded (int)
      int m_idSchLateTime;            // MSR_id for lateness at scheduler
      int m_idQualityRate;            // MSR_id for Quality rate requested
      int m_idQualityTime;            // MSR_id for Quality time requested
      int m_idDecision;               // MSR_id for decision code
      int m_idDuration;               // MSR_id for duration of a frame
      int m_idThrottle;               // MSR_id for audio-video throttling
      //int m_idDebug;                  // MSR_id for trace style debugging
      //int m_idSendQuality;          // MSR_id for timing the notifications per se
  endif // PERF
      REFERENCE_TIME m_trRememberStampForPerf;  // original time stamp of frame
                                                // with no earliness fudges etc.
  ifdef PERF
      REFERENCE_TIME m_trRememberFrameForPerf;  // time when previous frame rendered
  
      // debug...
      int m_idFrameAvg;
      int m_idWaitAvg;
  endif
  
      // PROPERTY PAGE
      // This has edit fields that show the user what's happening
      // These member variables hold these counts.
  
      int m_cFramesDropped;           // cumulative frames dropped IN THE RENDERER
      int m_cFramesDrawn;             // Frames since streaming started seen BY THE
                                      // RENDERER (some may be dropped upstream)
  
      // Next two support average sync offset and standard deviation of sync offset.
      LONGLONG m_iTotAcc;                  // Sum of accuracies in mSec
      LONGLONG m_iSumSqAcc;           // Sum of squares of (accuracies in mSec)
  
      // Next two allow jitter calculation.  Jitter is std deviation of frame time.
      REFERENCE_TIME m_trLastDraw;    // Time of prev frame (for inter-frame times)
      LONGLONG m_iSumSqFrameTime;     // Sum of squares of (inter-frame time in mSec)
      LONGLONG m_iSumFrameTime;            // Sum of inter-frame times in mSec
  
      // To get performance statistics on frame rate, jitter etc, we need
      // to record the lateness and inter-frame time.  What we actually need are the
      // data above (sum, sum of squares and number of entries for each) but the data
      // is generated just ahead of time and only later do we discover whether the
      // frame was actually drawn or not.  So we have to hang on to the data
      int m_trLate;                   // hold onto frame lateness
      int m_trFrame;                  // hold onto inter-frame time
  
      int m_tStreamingStart;          // if streaming then time streaming started
                                      // else time of last streaming session
                                      // used for property page statistics
  ifdef PERF
      LONGLONG m_llTimeOffset;        // timeGetTime()*10000+m_llTimeOffset==ref time
  endif
  
  public:
  
      CBaseVideoRenderer(REFCLSID RenderClass, // CLSID for this renderer
                         TCHAR *pName,         // Debug ONLY description
                         LPUNKNOWN pUnk,       // Aggregated owner object
                         HRESULT *phr);        // General OLE return code
  
      ~CBaseVideoRenderer();
  
      // IQualityControl methods - Notify allows audio-video throttling
  
      STDMETHODIMP SetSink( IQualityControl * piqc);
      STDMETHODIMP Notify( IBaseFilter * pSelf, Quality q);
  
      // These provide a full video quality management implementation
  
      void OnRenderStart(IMediaSample *pMediaSample);
      void OnRenderEnd(IMediaSample *pMediaSample);
      void OnWaitStart();
      void OnWaitEnd();
      HRESULT OnStartStreaming();
      HRESULT OnStopStreaming();
      void ThrottleWait();
  
      // Handle the statistics gathering for our quality management
  
      void PreparePerformanceData(int trLate, int trFrame);
      virtual void RecordFrameLateness(int trLate, int trFrame);
      virtual void OnDirectRender(IMediaSample *pMediaSample);
      virtual HRESULT ResetStreamingTimes();
      BOOL ScheduleSample(IMediaSample *pMediaSample);
      HRESULT ShouldDrawSampleNow(IMediaSample *pMediaSample,
                                  REFERENCE_TIME *ptrStart,
                                  REFERENCE_TIME *ptrEnd);
  
      virtual HRESULT SendQuality(REFERENCE_TIME trLate, REFERENCE_TIME trRealStream);
      STDMETHODIMP JoinFilterGraph(IFilterGraph * pGraph, LPCWSTR pName);
  
      //
      //  Do estimates for standard deviations for per-frame
      //  statistics
      //
      //  *piResult = (llSumSq - iTot * iTot / m_cFramesDrawn - 1) /
      //                            (m_cFramesDrawn - 2)
      //  or 0 if m_cFramesDrawn <= 3
      //
      HRESULT GetStdDev(
          int nSamples,
          int *piResult,
          LONGLONG llSumSq,
          LONGLONG iTot
      );
  public:
  
      // IQualProp property page support
  
      STDMETHODIMP get_FramesDroppedInRenderer(int *cFramesDropped);
      STDMETHODIMP get_FramesDrawn(int *pcFramesDrawn);
      STDMETHODIMP get_AvgFrameRate(int *piAvgFrameRate);
      STDMETHODIMP get_Jitter(int *piJitter);
      STDMETHODIMP get_AvgSyncOffset(int *piAvg);
      STDMETHODIMP get_DevSyncOffset(int *piDev);
  
      // Implement an IUnknown interface and expose IQualProp
  
      DECLARE_IUNKNOWN
      STDMETHODIMP NonDelegatingQueryInterface(REFIID riid,VOID **ppv);
  };

---

  
  endif // __RENBASE__
  
  

---

[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

---

(C) Æliens 20/2/2008

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---

---

Hush Online Technology hush@cs.vu.nl 03/12/09