Dirac - A Video Codec

Created by the British Broadcasting Corporation.


pixel_match.h
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37 
38 #ifndef _PIXEL_MATCH_H_
39 #define _PIXEL_MATCH_H_
40 
41 /* *************************************************************************
42 *
43 * Class for getting motion vectors to pixel-accuracy
44 *
45 * The class could be implemented in any number of ways. The approach taken
46 * has been to do hierarchical matching, which means doing block matching
47 * on smaller, downcoverted versions of the pictures in order to get a wider
48 * effective search range. At each level of searching the vectors discovered
49 * can be used as guides to the next level of searching, and in this way
50 * large motions can be detected easily. The danger is that the motions of
51 * small objects can be overlooked.
52 *
53 * *************************************************************************/
54 
55 #include <libdirac_common/common.h>
56 #include <libdirac_common/motion.h>
58 namespace dirac
59 {
60  class EncQueue;
61  class MvData;
62  class EncoderParams;
63  class PicArray;
64 
65 
67  {
68  public:
69 
71  PixelMatcher( const EncoderParams& encp);
72 
74  /* Do the searching.
75 
76  \param my_buffer the buffer of pictures from which pictures are taken
77  \param pic_num the number of the picture for which motion is to be estimated
78  \param mv_data class in which the measured motion vectors are stored, together with costs
79 
80  */
81  void DoSearch( EncQueue& my_buffer, int pic_num );
82 
83  private:
84 
85  // Member variables
86 
89 
92 
93  // the depth of the hierarchical match
94  int m_depth;
95 
96  // the level we're at (from 0 to depth)
97  int m_level;
98 
99  // the search-range sizes for the hierarchical match
100  int m_xr, m_yr;
101 
102  // the search-range sizes for when hierarchical match fails
104 
105  // the temporal distances to the reference pictures
106  int m_tdiff[2];
107 
108  // the picture sort - I, L1 or L2
110 
111  // list of candidate vectors for checking
113 
114  // Prediction used for each block. This is derived from neighbouring blocks
115  // and is used to control the variation in the motion vector field.
117 
118  // The value used in computing block cost means with a simple recursive filter
119  double m_rho;
120 
121  // The mean of the block cost
122  double m_cost_mean;
123 
124  // The mean of the square of the block cost
126 
127  private:
128 
129  // Functions
130 
132  void MakePicHierarchy(const PicArray& data, OneDArray< PicArray* >& down_data);
133 
135  void MakeMEDataHierarchy(const OneDArray< PicArray*>& down_data,
136  OneDArray< MEData* >& me_data_set );
137 
139  void TidyPics( OneDArray< PicArray*>& down_data );
140 
142  void TidyMEData( OneDArray< MEData*>& me_data_set );
143 
145  void MatchPic(const PicArray& ref_data , const PicArray& pic_data , MEData& me_data ,
146  const MvData& guide_data, const int ref_id);
147 
149  void DoBlock(const int xpos, const int ypos ,
150  const MvArray& guide_array,
151  BlockMatcher& block_match);
152 
153  };
154 
155 } // namespace dirac
156 
157 #endif

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