Method and system for selection of reference picture and mode decision

A system for reference picture selection and mode decision during motion estimation of a video sequence, the video sequence comprising a plurality of video frames, each of the plurality of video frames comprising a plurality of macroblocks, the system comprising:

• a. a reference picture selection module comprising:
• i. a rate distortion calculating module for calculating one or more full-pel rate distortion costs and one or more sub-pel rate distortion costs for each of one or more reference video frames, wherein the one or more reference video frames are a part of one or two reference lists;
• ii. a reference video frame selecting module for selecting one of the one or more reference video frames, wherein the reference video frame selecting module selects the reference video frame based on the one or more sub-pel rate distortion costs;
• and
• b. a mode decision module for selecting a mode from one or more modes for partitioning a macroblock, the mode decision module selects the mode based on the one or more full-pel rate distortion costs.

A computer program product for use with a computer, the computer program product comprising a computer usable medium having a computer readable program code embodied therein for reference picture selection and mode decision during motion estimation of a video sequence, the video sequence comprising a plurality of video frames, each of the plurality of video frames comprising a plurality of macroblocks, wherein one of the plurality of macroblocks of a current video frame is loaded from a video frame buffer, the computer program code performing:

• a. full-pixel search for each of one or more reference video frames, wherein the one or more reference video frames are a part of one or two reference lists, the full-pixel search being performed for calculating one or more full-pel rate distortion costs;
• b. selecting a mode from one or more modes, wherein the one or more modes are used for partitioning a macroblock, the selection being performed using one of the one or more reference video frames, the one of the one or more reference video frames having minimum of the one or more full-pel rate distortion costs;
• c. interpolation for each of the one or more reference video frames of the one or two reference lists, each of the one or more reference video frames implementing the selected mode;
• d. sub-pixel search for each of the one or more reference video frames, the sub-pixel search being performed for calculating one or more sub-pel rate distortion costs;
• and
• e. selecting one of the one or more reference video frames, the selection based on minimum of the one or more sub-pel rate distortion costs.