Patent ID: 7050504
Filing Date: 2006-05-23
Classification: H04N

Abstract:
1. A method of filtering reconstructed samples to minimise coding artifacts introduced at a block boundary in a block-based video encoder and/or decoder, the method having the steps of: (a) calculating a pair of indices used to access a table of a pair of corresponding activity threshold values, the indices calculated using an average quantization parameter and an offset parameter; (b) determining the activity threshold values based on the pair of indicies; (c) confirming whether the filtering process will modify the sample values on every line of samples for the block boundary by checking a content activity for the every line of samples for said block boundary, the content activity based on the determined activity threshold values; and (d) filtering the confirmed samples when the filtering strength, Bs, is not equal to zero wherein a pair of the activity threshold values are ALPHA (α) and BETA (β), and the average quantization parameter, QP av , was used in coding the two blocks that neighbour the block boundary, and the values of the activity threshold values, ALPHA(α) and BETA (β) for each possible value of the indices Index A and Index B are