Patent ID: 6456663
Filing Date: 2002-09-24
Classification: H04N

Abstract:
Apparatus, for use in a video decoder which decodes digital video signals that have been encoded into blocks of frequency domain coefficient values, to compensate for inverse transform mismatch errors which occur during conversion of a first resolution encoded video signal to a second resolution encoded video signal, wherein the second resolution is lower than the first resolution, the apparatus comprising:a mismatch control processor coupled to receive the blocks of frequency domain coefficient values and to process the blocks of frequency domain coefficient values according to a mismatch control algorithm to produce respective blocks of processed frequency domain coefficient values; a frequency domain filter having a plurality of frequency domain filter coefficients corresponding to a respective plurality of frequency bands, the frequency domain filter being coupled to receive the blocks of processed frequency domain coefficient values, for filtering the blocks of processed frequency domain coefficient values to provide respective blocks of low-pass filtered frequency domain coefficient values, wherein one of said frequency domain filter coefficients corresponding to a highest frequency band is set to 1; and an inverse frequency domain transform processor coupled to the frequency domain filter for transforming the blocks of low-pass filtered frequency domain coefficient values into spatial domain picture elements.