Spatial and temporal filtering in a low-cost MPEG bit rate transcoder

The MPEG bit-rate transcoder with motion compensation, MC-BRT, that exactly derives from a simplified synchronized decoder/encoder cascade, is considered. Such a transcoder is cost effective but lacks features such as spatial and temporal filtering. These features are known to improve the encoder performance at low bit-rates. Such features would be highly desirable in the MC-BRT since most applications now involve critical bit-rates. This paper shows that spatial and motion compensated temporal filtering can be implemented in the MC-BRT at a negligible cost. The filters are analyzed and control variables are given. Simulations reveal the efficiency of the method in terms of noise reduction as well as its great impact on image quality.