公开(公告)号：US20230142771A1

公开(公告)日：2023-05-11

申请号：US17979025

申请日：2022-11-02

Applicant: Apple Inc.

Inventor： Yixin DU ,  Alexandros TOURAPIS ,  Yunfei ZHENG ,  Jun XIN ,  Mukta S. Gore ,  Alican NALCI ,  Mei T. GUO ,  Yeqing WU ,  Hsi-Jung WU

IPC: H04N19/82 ,  H04N19/132 ,  H04N19/186 ,  H04N19/176

CPC classification number: H04N19/82 ,  H04N19/132 ,  H04N19/186 ,  H04N19/176

Abstract: A filtering system for video coders and decoders is disclosed that includes a feature detector having an input for samples reconstructed from coded video data representing a color component of source video, and having an output for data identifying a feature recognized therefrom, an offset calculator having an input for the feature identification data from the feature detector and having an output for a filter offset, and a filter having an input for the filter offset from the offset calculator and an input for the reconstructed samples, and having an output for filtered samples. The filtering system is expected to improve operations of video coder/decoder filtering systems by selecting filtering offsets from analysis of recovered video data in a common color plane as the samples that will be filtered.

公开(公告)号：US20230070492A1

公开(公告)日：2023-03-09

申请号：US17886858

申请日：2022-08-12

Applicant: Apple Inc.

Inventor： Jiancong Luo ,  Dzung T. Hoang ,  Francesco Iacopino ,  Linfeng Guo ,  Mukta S. Gore ,  Ryan Baldwin ,  Supradeep T. Rangarajan ,  Xiaohua Yang

IPC: H04N19/154 ,  H04N19/124 ,  H04N19/18 ,  H04N19/176

Abstract: Techniques for reducing reduce coding artifacts in video data are disclosed. In one aspect, a frame of video data is partitioned into pixel blocks, which are organized into slices. The pixel blocks of each slice are coded by a compression algorithm and an estimate of coding artifacts in the slice is made. For slices that are estimated to possess coding artifacts, the method revises coding parameters applied to pixel blocks in the slice and recodes the slice. The method substitutes recoded slices for originally-coded slices in frame, working in a priority order from a slice with the highest estimated likelihood of coding artifacts down to slices with lower estimated likelihoods of coding artifacts, measuring changes in the frame's coding size as it goes. The likelihood of coding artifacts can be estimated from slice statistics that may be developed from a comparison of transform coefficients among the pixel blocks within a slice, from an evaluation of transform coefficients of a pixel block with a slice that is estimated to have a lowest spatial complexity, or from coded luma data of the pixel blocks within a slice. In a further aspect, slice statistics may be computed from pixel block data only for a subset of slices within a frame. Slice statistics for other slices may be derived from the statistics of neighboring slices. In another aspect, a method may revise coding parameters in iterative fashion working from an initialized value and estimate (without recoding them) data sizes of coded slices that may be obtained from the revised parameters. As the method operates, it may compare the coding parameters to parameters used in a first iteration of coding and terminate the iterative process for that slice if the first iteration coding parameters are higher than the revised parameter.