DEBLOCKING OR DERINGING FILTER AND ENCODER, DECODER AND METHOD FOR APPLYING AND VARYING A STRENGTH OF A DEBLOCKING OR DERINGING FILTER

摘要

The invention concerns an encoder, a decoder and methods for applying and varying a strength of a deblocking or deringing filter (110, 120) for filtering a block (1000) of a picture (12), wherein the deblocking filter (110, 120) is configured to determine, for each of at least eight border portions (1011, 1012, 1013, 1014, 1021, 1022, 1023, 1024) of a border (1010) of the block (1000), a dissimilarity between an unfiltered content (1015) of the block (1000) and a surrounding picture content (1016) around the block (1000) along the respective border portion (1011, 1012, 1013, 1014, 1021, 1022, 1023, 1024), the eight border portions (1011, 1012, 1013, 1014, 1021, 1022, 1023, 1024) including four corner border portions (1021, 1022, 1023, 1024), each arranged at a corner of the block (1000), and four edge border portions (1011, 1012, 1013, 1014), each arranged at intermediary portions of the border (1010) between the corners of the block (1000). Furthermore, the deblocking filter is configured to parametrize a deblocking filtering of the block (1000) using the dissimilarities determined for the at least eight border portions (1011, 1012, 1013, 1014, 1021, 1022, 1023, 1024) in order to obtain a filtered content of the block (1000).