US 10,567,806 B2Granted

Method of block-based adaptive loop filtering

AssigneeMediatek Inc.

InventorsChia-Yang Tsai, Ching-Yeh Chen, Yu-Wen Huang

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Abstract

A method of adaptive loop filtering for reconstructed video to improve the performance is disclosed. In one embodiment, a loop filter is selected from one or more candidate filters including a circular symmetrical filter candidate. The candidate filters also may include a ½-symmetry filter candidate and a flag is used to select between different symmetries. In another embodiment, a priority-based block filter merge is disclosed. A filter merge list consisting of no more than a first number of filter candidates selected from corresponding filters used by corresponding set members in the neighboring block set is generated according to a priority order of the set members in the neighboring block set. In yet another embodiment, the loop filter is shared by reconstructed video in multiple image units of a same group. The filter merge groups are identified by differences of consecutive group indices.

Claims4

Dependent claims

A method of adaptive loop filtering for reconstructed video in a video encoder, the method comprising:

partitioning a picture of the reconstructed video into a first number of image units according to position of each pixel in the picture;
dividing the first number of image units into a second number of filter groups;
selecting a corresponding loop filter for each filter group;
applying the corresponding loop filter to first video data associated with all image units in said each filter group;
deriving a total number of image units in said each filter group based on an image unit index assigned for a first image unit in said each filter group;
signaling loop filter sharing associated with the second number of filter groups using a group index for said each filter group represented by the total number of image units in said each filter group, wherein the group index corresponds to an image unit index for a first image unit in each group;
and signaling filter information associated with each corresponding loop filter for the second number of filter groups, wherein the group index and the filter information associated with each corresponding loop filter of each filter group are incorporated in consecutive locations of a coded bitstream for all filter groups.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/034,115Filed 10 Nov 2014 · us provisional application
Priority: 15 Nov 2013
Published: US 2016/0269753 A115 Sep 2016
Granted: 18 Feb 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

H04N 19/82
Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation: involving filtering within a prediction loop
H04N 19/117
Characterised by the element, parameter or selection affected or controlled by the adaptive coding: filters, e.g. for pre-processing or…
H04N 19/119
Characterised by the element, parameter or selection affected or controlled by the adaptive coding: adaptive subdivision aspects, e.g. subdivision…
H04N 19/14
Incoming video signal characteristics or properties: coding unit complexity, e.g. amount of activity or edge presence estimation