Quality-adaptive requantization for low-energy MPEG-4 video decoding in mobile devices

Current mobile devices usually provide streaming media for users. While the online multimedia processing requires intensive computation, the characteristics of mobility and portability place a severe energy constraint on the system. In this paper, we aim to develop a systematic methodology for dealing with low-energy computation for the MPEG-4 video decoding. Our approach is based on a new fine-controllable, quality-adaptive technique to reduce data volumes, which results in energy saving. To do so, we introduce a requantization step to the video decoding process. The proposed requantization ensures that the energy consumption reduces at higher rate than the video quality degrades, and that the videos remain intelligible to a human viewer. The experimental results show that the energy consumption is reduced by up to 42% with 13% quality degradation, thereby confirming the efficacy of the quality-adaptive requantization.