Quality-aware Video Decoding on Thermally-constrained MPSoC Platforms

Current mobile devices extensively run video players that are power hungry. Further, higher power densities as a result of technology scaling results in higher on-chip temperatures. Unlike general purpose computer systems, mobile devices that run on batteries cannot afford to have expensive cooling mechanisms. Therefore, in order to satisfy thermal constraints while running power hungry applications, dynamic thermal management (DTM) techniques have been employed. For multimedia applications, the techniques primarily relied on dynamic voltage and frequency scaling (DVFS) and dynamic power management (DPM) while taking care that maximum video quality is achieved. However, no prior work has exploited frame drops to lower the inserted idle times under predetermined quality constraints. In this work, we propose a DPM framework that utilizes frame drops to dynamically insert low idle times in order to satisfy a peak temperature constraint under a given quality constraint. This also reduces the end-to-end latency. The latencies are further reduced by maintaining lightweight workload histories. For the videos used in our experiments, it was observed that a small reduction in quality of 2 dB (reduction from 32 dB to 30 dB) due to frame drops in motion videos results in a maximum latency reduction of 1.7 sec.