Motion-compensated temporal prefiltering for noise reduction in a video encoder

For coding efficiency as well as noise reduction, efficient prefiltering needs to be performed prior to video encoding. This paper presents a DCT-domain temporal filtering scheme in an MPEG video encoder. It is proven that the multiplication of every DCT coefficient in an inter block with a proper weight is equivalent to motion compensated temporal filtering in the spatial domain for the inter block. Also, we propose to determine properly the weight by using effective noise estimation scheme. Experimental results show that the proposed prefiltering scheme provides outstanding coding efficiency as well as noise reduction in an MPEG video encoder.