| //------------------------------------------------------------------------------ | |
| // File: VTrans.h | |
| // | |
| // Desc: DirectShow base classes - defines a video transform class. | |
| // | |
| // Copyright (c) 1992-2001 Microsoft Corporation. All rights reserved. | |
| //------------------------------------------------------------------------------ | |
| // This class is derived from CTransformFilter, but is specialised to handle | |
| // the requirements of video quality control by frame dropping. | |
| // This is a non-in-place transform, (i.e. it copies the data) such as a decoder. | |
| class CVideoTransformFilter : public CTransformFilter | |
| { | |
| public: | |
| CVideoTransformFilter(__in_opt LPCTSTR, __inout_opt LPUNKNOWN, REFCLSID clsid); | |
| ~CVideoTransformFilter(); | |
| HRESULT EndFlush(); | |
| // ================================================================= | |
| // ----- override these bits --------------------------------------- | |
| // ================================================================= | |
| // The following methods are in CTransformFilter which is inherited. | |
| // They are mentioned here for completeness | |
| // | |
| // These MUST be supplied in a derived class | |
| // | |
| // NOTE: | |
| // virtual HRESULT Transform(IMediaSample * pIn, IMediaSample *pOut); | |
| // virtual HRESULT CheckInputType(const CMediaType* mtIn) PURE; | |
| // virtual HRESULT CheckTransform | |
| // (const CMediaType* mtIn, const CMediaType* mtOut) PURE; | |
| // static CCOMObject * CreateInstance(LPUNKNOWN, HRESULT *); | |
| // virtual HRESULT DecideBufferSize | |
| // (IMemAllocator * pAllocator, ALLOCATOR_PROPERTIES *pprop) PURE; | |
| // virtual HRESULT GetMediaType(int iPosition, CMediaType *pMediaType) PURE; | |
| // | |
| // These MAY also be overridden | |
| // | |
| // virtual HRESULT StopStreaming(); | |
| // virtual HRESULT SetMediaType(PIN_DIRECTION direction,const CMediaType *pmt); | |
| // virtual HRESULT CheckConnect(PIN_DIRECTION dir,IPin *pPin); | |
| // virtual HRESULT BreakConnect(PIN_DIRECTION dir); | |
| // virtual HRESULT CompleteConnect(PIN_DIRECTION direction,IPin *pReceivePin); | |
| // virtual HRESULT EndOfStream(void); | |
| // virtual HRESULT BeginFlush(void); | |
| // virtual HRESULT EndFlush(void); | |
| // virtual HRESULT NewSegment | |
| // (REFERENCE_TIME tStart,REFERENCE_TIME tStop,double dRate); | |
| #ifdef PERF | |
| // If you override this - ensure that you register all these ids | |
| // as well as any of your own, | |
| virtual void RegisterPerfId() { | |
| m_idSkip = MSR_REGISTER(TEXT("Video Transform Skip frame")); | |
| m_idFrameType = MSR_REGISTER(TEXT("Video transform frame type")); | |
| m_idLate = MSR_REGISTER(TEXT("Video Transform Lateness")); | |
| m_idTimeTillKey = MSR_REGISTER(TEXT("Video Transform Estd. time to next key")); | |
| CTransformFilter::RegisterPerfId(); | |
| } | |
| #endif | |
| protected: | |
| // =========== QUALITY MANAGEMENT IMPLEMENTATION ======================== | |
| // Frames are assumed to come in three types: | |
| // Type 1: an AVI key frame or an MPEG I frame. | |
| // This frame can be decoded with no history. | |
| // Dropping this frame means that no further frame can be decoded | |
| // until the next type 1 frame. | |
| // Type 1 frames are sync points. | |
| // Type 2: an AVI non-key frame or an MPEG P frame. | |
| // This frame cannot be decoded unless the previous type 1 frame was | |
| // decoded and all type 2 frames since have been decoded. | |
| // Dropping this frame means that no further frame can be decoded | |
| // until the next type 1 frame. | |
| // Type 3: An MPEG B frame. | |
| // This frame cannot be decoded unless the previous type 1 or 2 frame | |
| // has been decoded AND the subsequent type 1 or 2 frame has also | |
| // been decoded. (This requires decoding the frames out of sequence). | |
| // Dropping this frame affects no other frames. This implementation | |
| // does not allow for these. All non-sync-point frames are treated | |
| // as being type 2. | |
| // | |
| // The spacing of frames of type 1 in a file is not guaranteed. There MUST | |
| // be a type 1 frame at (well, near) the start of the file in order to start | |
| // decoding at all. After that there could be one every half second or so, | |
| // there could be one at the start of each scene (aka "cut", "shot") or | |
| // there could be no more at all. | |
| // If there is only a single type 1 frame then NO FRAMES CAN BE DROPPED | |
| // without losing all the rest of the movie. There is no way to tell whether | |
| // this is the case, so we find that we are in the gambling business. | |
| // To try to improve the odds, we record the greatest interval between type 1s | |
| // that we have seen and we bet on things being no worse than this in the | |
| // future. | |
| // You can tell if it's a type 1 frame by calling IsSyncPoint(). | |
| // there is no architected way to test for a type 3, so you should override | |
| // the quality management here if you have B-frames. | |
| int m_nKeyFramePeriod; // the largest observed interval between type 1 frames | |
| // 1 means every frame is type 1, 2 means every other. | |
| int m_nFramesSinceKeyFrame; // Used to count frames since the last type 1. | |
| // becomes the new m_nKeyFramePeriod if greater. | |
| BOOL m_bSkipping; // we are skipping to the next type 1 frame | |
| #ifdef PERF | |
| int m_idFrameType; // MSR id Frame type. 1=Key, 2="non-key" | |
| int m_idSkip; // MSR id skipping | |
| int m_idLate; // MSR id lateness | |
| int m_idTimeTillKey; // MSR id for guessed time till next key frame. | |
| #endif | |
| virtual HRESULT StartStreaming(); | |
| HRESULT AbortPlayback(HRESULT hr); // if something bad happens | |
| HRESULT Receive(IMediaSample *pSample); | |
| HRESULT AlterQuality(Quality q); | |
| BOOL ShouldSkipFrame(IMediaSample * pIn); | |
| int m_itrLate; // lateness from last Quality message | |
| // (this overflows at 214 secs late). | |
| int m_tDecodeStart; // timeGetTime when decode started. | |
| int m_itrAvgDecode; // Average decode time in reference units. | |
| BOOL m_bNoSkip; // debug - no skipping. | |
| // We send an EC_QUALITY_CHANGE notification to the app if we have to degrade. | |
| // We send one when we start degrading, not one for every frame, this means | |
| // we track whether we've sent one yet. | |
| BOOL m_bQualityChanged; | |
| // When non-zero, don't pass anything to renderer until next keyframe | |
| // If there are few keys, give up and eventually draw something | |
| int m_nWaitForKey; | |
| }; |