Multi-Objective Design Space Exploration for the Optimization of the HEVC Mode Decision Process

TL;DR

This paper introduces a multi-objective design space exploration method for HEVC encoding that optimizes mode decision processes to improve encoding efficiency and energy consumption based on real measurements.

Contribution

It presents a novel multi-objective DSE framework that automatically optimizes HEVC encoder configurations for multiple criteria simultaneously.

Findings

Saved over 60% encoding time

Reduced decoding energy by 3%

Achieved these with around 3% bitrate increase

Abstract

Finding the best possible encoding decisions for compressing a video sequence is a highly complex problem. In this work, we propose a multi-objective Design Space Exploration (DSE) method to automatically find HEVC encoder implementations that are optimized for several different criteria. The DSE shall optimize the coding mode evaluation order of the mode decision process and jointly explore early skip conditions to minimize the four objectives a) bitrate, b) distortion, c) encoding time, and d) decoding energy. In this context, we use a SystemC-based actor model of the HM test model encoder for the evaluation of each explored solution. The evaluation that is based on real measurements shows that our framework can automatically generate encoder solutions that save more than 60% of encoding time or 3% of decoding energy when accepting bitrate increases of around 3%.