Sweet Streams are Made of This: The System Engineer's View on Energy Efficiency in Video Communications

TL;DR

This paper reviews the energy consumption of online video services from a system engineer's perspective, highlighting key factors, models, and potential savings, and discusses future directions for energy-efficient video streaming.

Contribution

It aggregates existing energy consumption models into a comprehensive global model and identifies end-user devices and encoding as key areas for energy savings.

Findings

End-user devices and encoding offer the largest potential for energy savings.

A comprehensive global energy consumption model for online video services is proposed.

Recent advances in energy efficiency for video streaming are summarized.

Abstract

In recent years, the global use of online video services has increased rapidly. Today, a manifold of applications, such as video streaming, video conferencing, live broadcasting, and social networks, make use of this technology. A recent study found that the development and the success of these services had as a consequence that, nowadays, more than 1% of the global greenhouse-gas emissions are related to online video, with growth rates close to 10% per year. This article reviews the latest findings concerning energy consumption of online video from the system engineer's perspective, where the system engineer is the designer and operator of a typical online video service. We discuss all relevant energy sinks, highlight dependencies with quality-of-service variables as well as video properties, review energy consumption models for different devices from the literature, and aggregate these existing models into a global model for the overall energy consumption of a generic online video service. Analyzing this model and its implications, we find that end-user devices and video encoding have the largest potential for energy savings. Finally, we provide an overview of recent advances in energy efficiency improvement for video streaming and propose future research directions for energy-efficient video streaming services.