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Advances in Multimedia
Volume 2007, Article ID 83715, 10 pages
Research Article

Quality-Based Backlight Optimization for Video Playback on Handheld Devices

1NVIDIA Corporation, Santa Clara, CA 95050, USA
2Motorola Labs, Schaumburg, IL 60196, USA
3Donald Bren School of Information and Computer Science, University of California, Irvine, CA 92697-3425, USA

Received 18 December 2006; Accepted 23 April 2007

Academic Editor: Haohong Wang

Copyright © 2007 Liang Cheng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


For a typical handheld device, the backlight accounts for a significant percentage of the total energy consumption (e.g., around 30% for a Compaq iPAQ 3650). Substantial energy savings can be achieved by dynamically adapting backlight intensity levels on such low-power portable devices. In this paper, we analyze the characteristics of video streaming services and propose a cross-layer optimization scheme called quality adapted backlight scaling (QABS) to achieve backlight energy savings for video playback applications on handheld devices. Specifically, we present a fast algorithm to optimize backlight dimming while keeping the degradation in image quality to a minimum so that the overall service quality is close to a specified threshold. Additionally, we propose two effective techniques to prevent frequent backlight switching, which negatively affects user perception of video. Our initial experimental results indicate that the energy used for backlight is significantly reduced, while the desired quality is satisfied. The proposed algorithms can be realized in real time.