Complexity reduction of H.264 using Lagrange optimization methods

Abstract

A complexity reduction algorithm for an H.264 encoder is proposed. Computational savings are achieved by identifying, prior to motion estimation, macroblocks that are likely to be skipped and hence saving further computational processing of these macroblocks. This early prediction is made by estimating a Lagrangian rate-distortion cost function which incorporates an adaptive model for the Lagrange multiplier parameter based on local sequence statistics. Simulation results demonstrate that the algorithm can achieve computational savings of 19-65% (depending on the source sequence) with no significant loss of rate-distortion performance.

Complexity-constrained H.264 HD video coding through mode ranking

“…In exploring the variety of macroblock partitions available in H.264/AVC, there are works [10,11] that only carry motion estimation for the most probable partition. The early prediction of skipped macroblocks prior to motion estimation [12,13] is also used for complexity control. Intraprediction tests can also be reduced by means of selecting the most probable best mode according to heuristics [14,15].…”

Efficient mode selection for H.264 complexity reduction in a Bayesian framework

“…[19,20], we have previously proposed methods for fast mode choice based on estimating and comparing rate-distortion costs of skipping versus coding a macroblock. Early prediction of macroblock mode choice is made by estimating a Lagrangian rate-distortion cost function that incorporates an adaptive model for the Lagrange multiplier parameter based on local sequence statistics and then utilizing this cost in the decision process.…”

Design of the H264 application and Implementation on Heterogeneous Architectures

“…Parallel decoding techniques of H.264 exist from the highest level, which is the group of frames or pictures (GOP), the coarse-grain level, till the lowest level, which is the block inside a macroblock, the fine-grain level. Kannangara [5] reduced the complexity of the H.264 decoder (19-65%) by predicting the SKIP macroblocks using an estimation based on a Lagrangian ratedistortion cost function. Gurhanli [6] suggested a parallel approach by decoding independent groups of frames on different cores.…”