Non-integer bit estimation for enhanced inter-picture prediction in H.265/HEVC

Abstract

Many modern video encoders use the Lagrangian rate-distortion optimization (RDO) algorithm for mode decisions during the compression procedure. This paper proposes to increase the accuracy of inter picture prediction in H.265, by computing a non-integer number of bits for arithmetic coding of the syntax elements. During the RDO process the distortion and bit rate of each mode has to be estimated and a more accurate estimation leads to better-optimized decisions. Our method offers a significant gain in RDO performance, with simulations showing that an average bit-rate saving of up to 16.0% can be achieved for the H.265/HEVC codec.