  In this paper, we study decoding energy reduction opportunities using
temporal-domain filtering and subsampling methods. In particular, we study
spatiotemporal filtering using a contrast sensitivity function and temporal
downscaling, i.e., frame rate reduction. We apply these concepts as a
pre-filtering to the video before compression and evaluate the bitrate, the
decoding energy, and the visual quality with a dedicated metric targeting
temporally down-scaled sequences. We find that decoding energy savings yield
35% when halving the frame rate and that spatiotemporal filtering can lead to
up to 5% of additional savings, depending on the content.
