Patent ID: 8385411

Claim:
A method of decoding a video signal, comprising: obtaining, by a video decoding apparatus, first flag information indicating whether an adaptive filter is applied or not; obtaining, by the video decoding apparatus, second flag information when the first flag information indicates that the adaptive filter is applied, the second flag information indicating whether filter coefficients of an N th adaptive filter is derived from filter coefficients of an (N−1) th adaptive filter; obtaining, by the video decoding apparatus, the filter coefficients of the N th adaptive filter by adding difference filter coefficients of the N th adaptive filter to prediction filter coefficients, when the second flag information indicates that the filter coefficients of the N th adaptive filter is derived from the filter coefficients of the (N−1) th adaptive filter, wherein the difference filter coefficients of the N th adaptive filter is extracted from the video signal, the difference filter coefficients of the N th adaptive filter being a difference between the prediction filter coefficients and the filter coefficients of the N th adaptive filter, the prediction filter coefficients being the filter coefficients of the (N−1) th adaptive filter, N being a natural number greater than 1; performing by a deblocking filtering unit, a deblocking filtering on a decoded picture; and performing, by an adaptive filtering unit, an adaptive filtering on the deblocking-filtered and decoded picture by using the filter coefficients of the N th adaptive filter.