Extending the Lifetime of Portable Video Communication Devices Using Power-Rate-Distortion Optimization

In this paper, we develop a new framework to save the data processing energy and extend the operational lifetime of portable video communication devices. Video compression is computationally intensive and energy-consuming. However, portable video communication devices, powered by batteries, have limited energy supply for data processing. One of the central challenging issues in portable video communication system design is to minimize the energy consumption of video compression so as to extend the operational lifetime of devices. Currently, there are a lot of software and hardware techniques developed by researchers and practitioners to reduce the energy consumption of video compression. In this work, we demonstrate that, given a video encoder, which has already been fully optimized using existing software and hardware techniques, we can further reduce its energy consumption significantly using power-rate-distortion (P-R-D) optimization. Theoretically, we show that extending the traditional rate-distortion (R-D) analysis to P-R-D analysis gives us another dimension of flexibility in resource allocation and performance optimization. Within this new P-R-D optimization framework, we are able to trade “bits” for “joules” (energy) so as to save energy. We analyze the energy saving performance of P-R-D optimization. We develop an adaptive scheme to estimate the P-R-D model parameters and perform online energy optimization and control for real-time video compression. Our results show that, for typical videos with non-stationary scene statistics, using the proposed P-R-D optimization technology, the operational lifetime of the video communication devices can be significantly extended, or even doubled. This has a significant impact on energy-efficient portable video communication system design.