Many implementations of MPEG-2 decoder permit a certain degradation in PSNR due to human audio/video perceptory imperfections. This paper presents a technique for exploiting the acceptable degradation in PSNR towards energy minimization by application of dynamic voltage management techniques. The technique is based on a two phase approach that includes static characterization and dynamic adaptation. We present a novel model that relates the type of the frame, size of the frame, and number of macroblocks processed to the PSNR of the stream. The model is utilized for characterizing the benchmark streams. The results of static characterizations are then applied towards general streams by dynamic adaptations. The experimental results demonstrate that for an acceptable PSNR of 30 to 32dB the technique results in energy savings from 24% to over 85%.