src/filters/BaseClasses/transfrm.h

   1 //------------------------------------------------------------------------------
   2 // File: Transfrm.h
   3 //
   4 // Desc: DirectShow base classes - defines classes from which simple
   5 //       transform codecs may be derived.
   6 //
   7 // Copyright (c) 1992-2002 Microsoft Corporation.  All rights reserved.
   8 //------------------------------------------------------------------------------
   9
  10
  11 // It assumes the codec has one input and one output stream, and has no
  12 // interest in memory management, interface negotiation or anything else.
  13 //
  14 // derive your class from this, and supply Transform and the media type/format
  15 // negotiation functions. Implement that class, compile and link and
  16 // you're done.
  17
  18
  19 #ifndef __TRANSFRM__
  20 #define __TRANSFRM__
  21
  22 // ======================================================================
  23 // This is the com object that represents a simple transform filter. It
  24 // supports IBaseFilter, IMediaFilter and two pins through nested interfaces
  25 // ======================================================================
  26
  27 class CTransformFilter;
  28
  29 // ==================================================
  30 // Implements the input pin
  31 // ==================================================
  32
  33 class CTransformInputPin : public CBaseInputPin
  34 {
  35     friend class CTransformFilter;
  36
  37 protected:
  38     CTransformFilter *m_pTransformFilter;
  39
  40
  41 public:
  42
  43     CTransformInputPin(
  44         TCHAR *pObjectName,
  45         CTransformFilter *pTransformFilter,
  46         HRESULT * phr,
  47         LPCWSTR pName);
  48 #ifdef UNICODE
  49     CTransformInputPin(
  50         char *pObjectName,
  51         CTransformFilter *pTransformFilter,
  52         HRESULT * phr,
  53         LPCWSTR pName);
  54 #endif
  55
  56     STDMETHODIMP QueryId(LPWSTR * Id)
  57     {
  58         return AMGetWideString(L"In", Id);
  59     }
  60
  61     // Grab and release extra interfaces if required
  62
  63     HRESULT CheckConnect(IPin *pPin);
  64     HRESULT BreakConnect();
  65     HRESULT CompleteConnect(IPin *pReceivePin);
  66
  67     // check that we can support this output type
  68     HRESULT CheckMediaType(const CMediaType* mtIn);
  69
  70     // set the connection media type
  71     HRESULT SetMediaType(const CMediaType* mt);
  72
  73     // --- IMemInputPin -----
  74
  75     // here's the next block of data from the stream.
  76     // AddRef it yourself if you need to hold it beyond the end
  77     // of this call.
  78     STDMETHODIMP Receive(IMediaSample * pSample);
  79
  80     // provide EndOfStream that passes straight downstream
  81     // (there is no queued data)
  82     STDMETHODIMP EndOfStream(void);
  83
  84     // passes it to CTransformFilter::BeginFlush
  85     STDMETHODIMP BeginFlush(void);
  86
  87     // passes it to CTransformFilter::EndFlush
  88     STDMETHODIMP EndFlush(void);
  89
  90     STDMETHODIMP NewSegment(
  91                         REFERENCE_TIME tStart,
  92                         REFERENCE_TIME tStop,
  93                         double dRate);
  94
  95     // Check if it's OK to process samples
  96     virtual HRESULT CheckStreaming();
  97
  98     // Media type
  99 public:
 100     CMediaType& CurrentMediaType() { return m_mt; };
 101
 102 };
 103
 104 // ==================================================
 105 // Implements the output pin
 106 // ==================================================
 107
 108 class CTransformOutputPin : public CBaseOutputPin
 109 {
 110     friend class CTransformFilter;
 111
 112 protected:
 113     CTransformFilter *m_pTransformFilter;
 114
 115 public:
 116
 117     // implement IMediaPosition by passing upstream
 118     IUnknown * m_pPosition;
 119
 120     CTransformOutputPin(
 121         TCHAR *pObjectName,
 122         CTransformFilter *pTransformFilter,
 123         HRESULT * phr,
 124         LPCWSTR pName);
 125 #ifdef UNICODE
 126     CTransformOutputPin(
 127         CHAR *pObjectName,
 128         CTransformFilter *pTransformFilter,
 129         HRESULT * phr,
 130         LPCWSTR pName);
 131 #endif
 132     ~CTransformOutputPin();
 133
 134     // override to expose IMediaPosition
 135     STDMETHODIMP NonDelegatingQueryInterface(REFIID riid, void **ppv);
 136
 137     // --- CBaseOutputPin ------------
 138
 139     STDMETHODIMP QueryId(LPWSTR * Id)
 140     {
 141         return AMGetWideString(L"Out", Id);
 142     }
 143
 144     // Grab and release extra interfaces if required
 145
 146     HRESULT CheckConnect(IPin *pPin);
 147     HRESULT BreakConnect();
 148     HRESULT CompleteConnect(IPin *pReceivePin);
 149
 150     // check that we can support this output type
 151     HRESULT CheckMediaType(const CMediaType* mtOut);
 152
 153     // set the connection media type
 154     HRESULT SetMediaType(const CMediaType *pmt);
 155
 156     // called from CBaseOutputPin during connection to ask for
 157     // the count and size of buffers we need.
 158     HRESULT DecideBufferSize(
 159                 IMemAllocator * pAlloc,
 160                 ALLOCATOR_PROPERTIES *pProp);
 161
 162     // returns the preferred formats for a pin
 163     HRESULT GetMediaType(int iPosition,CMediaType *pMediaType);
 164
 165     // inherited from IQualityControl via CBasePin
 166     STDMETHODIMP Notify(IBaseFilter * pSender, Quality q);
 167
 168     // Media type
 169 public:
 170     CMediaType& CurrentMediaType() { return m_mt; };
 171 };
 172
 173
 174 class AM_NOVTABLE CTransformFilter : public CBaseFilter
 175 {
 176
 177 public:
 178
 179     // map getpin/getpincount for base enum of pins to owner
 180     // override this to return more specialised pin objects
 181
 182     virtual int GetPinCount();
 183     virtual CBasePin * GetPin(int n);
 184     STDMETHODIMP FindPin(LPCWSTR Id, IPin **ppPin);
 185
 186     // override state changes to allow derived transform filter
 187     // to control streaming start/stop
 188     STDMETHODIMP Stop();
 189     STDMETHODIMP Pause();
 190
 191 public:
 192
 193     CTransformFilter(TCHAR *, LPUNKNOWN, REFCLSID clsid);
 194 #ifdef UNICODE
 195     CTransformFilter(CHAR *, LPUNKNOWN, REFCLSID clsid);
 196 #endif
 197     ~CTransformFilter();
 198
 199     // =================================================================
 200     // ----- override these bits ---------------------------------------
 201     // =================================================================
 202
 203     // These must be supplied in a derived class
 204
 205     virtual HRESULT Transform(IMediaSample * pIn, IMediaSample *pOut);
 206
 207     // check if you can support mtIn
 208     virtual HRESULT CheckInputType(const CMediaType* mtIn) PURE;
 209
 210     // check if you can support the transform from this input to this output
 211     virtual HRESULT CheckTransform(const CMediaType* mtIn, const CMediaType* mtOut) PURE;
 212
 213     // this goes in the factory template table to create new instances
 214     // static CCOMObject * CreateInstance(LPUNKNOWN, HRESULT *);
 215
 216     // call the SetProperties function with appropriate arguments
 217     virtual HRESULT DecideBufferSize(
 218                         IMemAllocator * pAllocator,
 219                         ALLOCATOR_PROPERTIES *pprop) PURE;
 220
 221     // override to suggest OUTPUT pin media types
 222     virtual HRESULT GetMediaType(int iPosition, CMediaType *pMediaType) PURE;
 223
 224
 225
 226     // =================================================================
 227     // ----- Optional Override Methods           -----------------------
 228     // =================================================================
 229
 230     // you can also override these if you want to know about streaming
 231     virtual HRESULT StartStreaming();
 232     virtual HRESULT StopStreaming();
 233
 234     // override if you can do anything constructive with quality notifications
 235     virtual HRESULT AlterQuality(Quality q);
 236
 237     // override this to know when the media type is actually set
 238     virtual HRESULT SetMediaType(PIN_DIRECTION direction,const CMediaType *pmt);
 239
 240     // chance to grab extra interfaces on connection
 241     virtual HRESULT CheckConnect(PIN_DIRECTION dir,IPin *pPin);
 242     virtual HRESULT BreakConnect(PIN_DIRECTION dir);
 243     virtual HRESULT CompleteConnect(PIN_DIRECTION direction,IPin *pReceivePin);
 244
 245     // chance to customize the transform process
 246     virtual HRESULT Receive(IMediaSample *pSample);
 247
 248     // Standard setup for output sample
 249     HRESULT InitializeOutputSample(IMediaSample *pSample, IMediaSample **ppOutSample);
 250
 251     // if you override Receive, you may need to override these three too
 252     virtual HRESULT EndOfStream(void);
 253     virtual HRESULT BeginFlush(void);
 254     virtual HRESULT EndFlush(void);
 255     virtual HRESULT NewSegment(
 256                         REFERENCE_TIME tStart,
 257                         REFERENCE_TIME tStop,
 258                         double dRate);
 259
 260 #ifdef PERF
 261     // Override to register performance measurement with a less generic string
 262     // You should do this to avoid confusion with other filters
 263     virtual void RegisterPerfId()
 264          {m_idTransform = MSR_REGISTER(TEXT("Transform"));}
 265 #endif // PERF
 266
 267
 268 // implementation details
 269
 270 protected:
 271
 272 #ifdef PERF
 273     int m_idTransform;                 // performance measuring id
 274 #endif
 275     BOOL m_bEOSDelivered;              // have we sent EndOfStream
 276     BOOL m_bSampleSkipped;             // Did we just skip a frame
 277     BOOL m_bQualityChanged;            // Have we degraded?
 278
 279     // critical section protecting filter state.
 280
 281     CCritSec m_csFilter;
 282
 283     // critical section stopping state changes (ie Stop) while we're
 284     // processing a sample.
 285     //
 286     // This critical section is held when processing
 287     // events that occur on the receive thread - Receive() and EndOfStream().
 288     //
 289     // If you want to hold both m_csReceive and m_csFilter then grab
 290     // m_csFilter FIRST - like CTransformFilter::Stop() does.
 291
 292     CCritSec m_csReceive;
 293
 294     // these hold our input and output pins
 295
 296     friend class CTransformInputPin;
 297     friend class CTransformOutputPin;
 298     CTransformInputPin *m_pInput;
 299     CTransformOutputPin *m_pOutput;
 300 };
 301
 302 #endif /* __TRANSFRM__ */
 303
 304