Power-aware video decoding using real-time event handlers

Abstract

Multimedia applications have to receive sufficient resource allocations to maintain their desired levels of Quality of Service (QoS). On the other hand, in mobile environments, the devices on which these applications must run have to minimize power consumption to prolong battery life. Our work focuses on the QoS issues in the event-driven distribution of multimedia streams between mobile users, where a source provides interactive video in the form of streams of data events to multiple remote sinks. This paper addresses the power-aware execution of event handlers at such event sinks. In particular, an adaptive approach to the dynamic selection of a suitable CPU clock frequency of a mobile device is shown superior to non-adaptive power management. This approach (a) minimizes power consumption while also (b) guaranteeing that a given event handler finishes its execution within application-specific timing constraints. This is realized by dynamically measuring the progress of event handler functions and then using this information to re-adjust the clock frequency for the current event and to select appropriate clock frequencies for future events.