src/filters/BaseClasses/transip.h

   1 //------------------------------------------------------------------------------
   2 // File: TransIP.h
   3 //
   4 // Desc: DirectShow base classes - defines classes from which simple
   5 //       Transform-In-Place filters may be derived.
   6 //
   7 // Copyright (c) 1992-2002 Microsoft Corporation.  All rights reserved.
   8 //------------------------------------------------------------------------------
   9
  10
  11 //
  12 // The difference between this and Transfrm.h is that Transfrm copies the data.
  13 //
  14 // It assumes the filter has one input and one output stream, and has no
  15 // interest in memory management, interface negotiation or anything else.
  16 //
  17 // Derive your class from this, and supply Transform and the media type/format
  18 // negotiation functions. Implement that class, compile and link and
  19 // you're done.
  20
  21
  22 #ifndef __TRANSIP__
  23 #define __TRANSIP__
  24
  25 // ======================================================================
  26 // This is the com object that represents a simple transform filter. It
  27 // supports IBaseFilter, IMediaFilter and two pins through nested interfaces
  28 // ======================================================================
  29
  30 class CTransInPlaceFilter;
  31
  32 // Several of the pin functions call filter functions to do the work,
  33 // so you can often use the pin classes unaltered, just overriding the
  34 // functions in CTransInPlaceFilter.  If that's not enough and you want
  35 // to derive your own pin class, override GetPin in the filter to supply
  36 // your own pin classes to the filter.
  37
  38 // ==================================================
  39 // Implements the input pin
  40 // ==================================================
  41
  42 class CTransInPlaceInputPin : public CTransformInputPin
  43 {
  44
  45 protected:
  46     CTransInPlaceFilter * const m_pTIPFilter;    // our filter
  47     BOOL                 m_bReadOnly;    // incoming stream is read only
  48
  49 public:
  50
  51     CTransInPlaceInputPin(
  52         TCHAR               *pObjectName,
  53         CTransInPlaceFilter *pFilter,
  54         HRESULT             *phr,
  55         LPCWSTR              pName);
  56
  57     // --- IMemInputPin -----
  58
  59     // Provide an enumerator for media types by getting one from downstream
  60     STDMETHODIMP EnumMediaTypes( IEnumMediaTypes **ppEnum );
  61
  62     // Say whether media type is acceptable.
  63     HRESULT CheckMediaType(const CMediaType* pmt);
  64
  65     // Return our upstream allocator
  66     STDMETHODIMP GetAllocator(IMemAllocator ** ppAllocator);
  67
  68     // get told which allocator the upstream output pin is actually
  69     // going to use.
  70     STDMETHODIMP NotifyAllocator(IMemAllocator * pAllocator,
  71                                  BOOL bReadOnly);
  72
  73     // Allow the filter to see what allocator we have
  74     // N.B. This does NOT AddRef
  75     IMemAllocator * PeekAllocator() const
  76         {  return m_pAllocator; }
  77
  78     // Pass this on downstream if it ever gets called.
  79     STDMETHODIMP GetAllocatorRequirements(ALLOCATOR_PROPERTIES *pProps);
  80
  81     HRESULT CompleteConnect(IPin *pReceivePin);
  82
  83     inline const BOOL ReadOnly() { return m_bReadOnly ; }
  84
  85 };  // CTransInPlaceInputPin
  86
  87 // ==================================================
  88 // Implements the output pin
  89 // ==================================================
  90
  91 class CTransInPlaceOutputPin : public CTransformOutputPin
  92 {
  93
  94 protected:
  95     // m_pFilter points to our CBaseFilter
  96     CTransInPlaceFilter * const m_pTIPFilter;
  97
  98 public:
  99
 100     CTransInPlaceOutputPin(
 101         TCHAR               *pObjectName,
 102         CTransInPlaceFilter *pFilter,
 103         HRESULT             *phr,
 104         LPCWSTR              pName);
 105
 106
 107     // --- CBaseOutputPin ------------
 108
 109     // negotiate the allocator and its buffer size/count
 110     // Insists on using our own allocator.  (Actually the one upstream of us).
 111     // We don't override this - instead we just agree the default
 112     // then let the upstream filter decide for itself on reconnect
 113     // virtual HRESULT DecideAllocator(IMemInputPin * pPin, IMemAllocator ** pAlloc);
 114
 115     // Provide a media type enumerator.  Get it from upstream.
 116     STDMETHODIMP EnumMediaTypes( IEnumMediaTypes **ppEnum );
 117
 118     // Say whether media type is acceptable.
 119     HRESULT CheckMediaType(const CMediaType* pmt);
 120
 121     //  This just saves the allocator being used on the output pin
 122     //  Also called by input pin's GetAllocator()
 123     void SetAllocator(IMemAllocator * pAllocator);
 124
 125     IMemInputPin * ConnectedIMemInputPin()
 126         { return m_pInputPin; }
 127
 128     // Allow the filter to see what allocator we have
 129     // N.B. This does NOT AddRef
 130     IMemAllocator * PeekAllocator() const
 131         {  return m_pAllocator; }
 132
 133     HRESULT CompleteConnect(IPin *pReceivePin);
 134
 135 };  // CTransInPlaceOutputPin
 136
 137
 138 class AM_NOVTABLE CTransInPlaceFilter : public CTransformFilter
 139 {
 140
 141 public:
 142
 143     // map getpin/getpincount for base enum of pins to owner
 144     // override this to return more specialised pin objects
 145
 146     virtual CBasePin *GetPin(int n);
 147
 148 public:
 149
 150     //  Set bModifiesData == false if your derived filter does
 151     //  not modify the data samples (for instance it's just copying
 152     //  them somewhere else or looking at the timestamps).
 153
 154     CTransInPlaceFilter(TCHAR *, LPUNKNOWN, REFCLSID clsid, HRESULT *,
 155                         bool bModifiesData = true);
 156 #ifdef UNICODE
 157     CTransInPlaceFilter(CHAR *, LPUNKNOWN, REFCLSID clsid, HRESULT *,
 158                         bool bModifiesData = true);
 159 #endif
 160     // The following are defined to avoid undefined pure virtuals.
 161     // Even if they are never called, they will give linkage warnings/errors
 162
 163     // We override EnumMediaTypes to bypass the transform class enumerator
 164     // which would otherwise call this.
 165     HRESULT GetMediaType(int iPosition, CMediaType *pMediaType)
 166         {   DbgBreak("CTransInPlaceFilter::GetMediaType should never be called");
 167             return E_UNEXPECTED;
 168         }
 169
 170     // This is called when we actually have to provide out own allocator.
 171     HRESULT DecideBufferSize(IMemAllocator*, ALLOCATOR_PROPERTIES *);
 172
 173     // The functions which call this in CTransform are overridden in this
 174     // class to call CheckInputType with the assumption that the type
 175     // does not change.  In Debug builds some calls will be made and
 176     // we just ensure that they do not assert.
 177     HRESULT CheckTransform(const CMediaType *mtIn, const CMediaType *mtOut)
 178     {
 179         return S_OK;
 180     };
 181
 182
 183     // =================================================================
 184     // ----- You may want to override this -----------------------------
 185     // =================================================================
 186
 187     HRESULT CompleteConnect(PIN_DIRECTION dir,IPin *pReceivePin);
 188
 189     // chance to customize the transform process
 190     virtual HRESULT Receive(IMediaSample *pSample);
 191
 192     // =================================================================
 193     // ----- You MUST override these -----------------------------------
 194     // =================================================================
 195
 196     virtual HRESULT Transform(IMediaSample *pSample) PURE;
 197
 198     // this goes in the factory template table to create new instances
 199     // static CCOMObject * CreateInstance(LPUNKNOWN, HRESULT *);
 200
 201
 202 #ifdef PERF
 203     // Override to register performance measurement with a less generic string
 204     // You should do this to avoid confusion with other filters
 205     virtual void RegisterPerfId()
 206          {m_idTransInPlace = MSR_REGISTER(TEXT("TransInPlace"));}
 207 #endif // PERF
 208
 209
 210 // implementation details
 211
 212 protected:
 213
 214     IMediaSample * CTransInPlaceFilter::Copy(IMediaSample *pSource);
 215
 216 #ifdef PERF
 217     int m_idTransInPlace;                 // performance measuring id
 218 #endif // PERF
 219     bool  m_bModifiesData;                // Does this filter change the data?
 220
 221     // these hold our input and output pins
 222
 223     friend class CTransInPlaceInputPin;
 224     friend class CTransInPlaceOutputPin;
 225
 226     CTransInPlaceInputPin  *InputPin() const
 227     {
 228         return (CTransInPlaceInputPin *)m_pInput;
 229     };
 230     CTransInPlaceOutputPin *OutputPin() const
 231     {
 232         return (CTransInPlaceOutputPin *)m_pOutput;
 233     };
 234
 235     //  Helper to see if the input and output types match
 236     BOOL TypesMatch()
 237     {
 238         return InputPin()->CurrentMediaType() ==
 239                OutputPin()->CurrentMediaType();
 240     }
 241
 242     //  Are the input and output allocators different?
 243     BOOL UsingDifferentAllocators() const
 244     {
 245         return InputPin()->PeekAllocator() != OutputPin()->PeekAllocator();
 246     }
 247 }; // CTransInPlaceFilter
 248
 249 #endif /* __TRANSIP__ */
 250