An efficient computation-constrained block-based motion estimation algorithm for low bit rate video coding

We present an efficient computation constrained block-based motion vector e stimation algorithm for low bit rate video coding that yields good tradeoff s between motion estimation distortion and number of computations. A reliab le predictor determines the search origin, localizing the search process. A n efficient search pattern exploits structural constraints within the motio n field. A flexible cost measure used to terminate the search allows simult aneous control of the motion estimation distortion and the computational co st. Experimental results demonstrate the viability of the proposed algorith m in low bit rate video coding applications. The resulting low bit rate vid eo encoder yields essentially the same levels of rate-distortion performanc e and subjective quality achieved by the UBC H.263+ video coding reference software. However. the proposed motion estimation algorithm provides substa ntially higher encoding speed as well as graceful computational degradation capabilities.