Down conversion system using a pre-decimation filter

摘要

An HDTV down conversion system including an apparatus for forming a low resolution video signal from an encoded video signal representing a video image. The encoded video signal is a frequency-domain transformed high resolution video signal with motion vectors. The apparatus includes a receiver for receiving the encoded video signal as a plurality of blocks of high resolution frequency-domain video coefficient values. A plurality of blocks comprises a macroblock. A down-conversion filter weights selected ones of the high resolution frequency-domain video coefficient values within each block to generate corresponding blocks of filtered frequency-domain video coefficients. An inverse-transform processor transforms each block of filtered frequency-domain video coefficients into a block of first-filtered pixel values. A pre-decimation filter performs inter-macroblock inter-block filtering of the plurality of blocks of first-filtered pixel values and provides corresponding blocks of second-filtered pixel values. A decimating processor deletes selected ones of the second-filtered pixel values within each block to provide blocks of low resolution video signal pixel values.