A Frequent-Domain VideoTranscoder with Spatial Downscaling for H.264/AVC

Wireless video communication is an important application supported by 3G mobile communication systems. In many applications,the pre-encoded video needs to be transcoded to lower spatial resolution to fit for various display screen sizes on mobile terminal devices. In this paper, we propose a fast video transcoder,working entirely in the frequent-domain, to convert high quality H.264/AVC bitstream into low bit rate stream with low spatial resolution for wireless video access. Simulation results show that the computational complexity of the proposed transcoder is less than 40% of that required by cascaded pixel-domain transcoder, however, the video quality achieved by the proposed method and by the pixel-domain methods is hardly distinguishable.