Adaptive Critic Design for Energy Minimization of Portable Video Communication Devices

Portable video communication devices operate on batteries with limited energy supply. Video compression is computationally intensive and energy-demanding. Therefore, one critical issue in portable video communication system design is to minimize the energy consumption of video encoding so as to prolong the operational lifetime of portable video devices. In this paper, we explore advanced methods in adaptive system control and develop an online complexity control and energy minimization scheme for real-time video encoding. More specifically, we introduce a set of parameters to control the computational complexity and energy consumption of the video encoder. We consider this video encoder as a nonlinear control system. Based on adaptive critic design, an advanced adaptive control method recently developed in control science, we design an online control scheme which is able to select the best configuration of complexity control parameters to minimize the energy consumption under rate-distortion constraints, or equivalently maximize video quality under rate and energy constraints. Our extensive experimental results demonstrate that the proposed scheme approaches the true optimum performance. The proposed online complexity control and energy minimization scheme will provide an important tool for energy minimization of portable video devices.