Fast mode decision making for interframe encoding

Abstract

An encoder achieves improved encoding efficiency by initially limiting consideration of the potential modes (block sizes) to a prescribed sub-set and by performing mode estimation jointly with mode decision-making. An initial sub-set of modes is considered and an estimation of the motion for each block in the sub-set is made to establish a best motion vector. A distortion measure is also made for each sub-set. From the distortion measure, a determination is made whether or not to estimate the motion for other block sizes. If not, then an encoding mode is chosen in accordance with the estimated motion. In this way, motion estimation on all possible block sizes need not be undertaken.

Description

[0001] This application claims priority under 35 U.S.C 119(e) to U.S. Provisional Patent Application Serial No. 60 / 439,296, filed January 10, 2003, the teachings of which are incorporated herein. technical field [0002] The present invention relates to a technique for reducing the computational complexity of video encoding while maintaining video compression efficiency. Background technique [0003] Various techniques currently exist to compress (encode) video streams for storage and transmission. Many known encoding techniques rely on both spatial and temporal similarity. The proposed H.264 coding technique (also known as JVT and MPEG AVC) specifies inter and intra coding (P and B frames) for inter frames. Each individual macroblock can be intra-coded, ie using spatial correlation, or inter-coded with temporal correlation from a previously coded frame. Usually, the encoder makes an inter / intra coding decision for each macroblock based on coding efficiency and subjective ...

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