公开(公告)号：US20250142059A1

公开(公告)日：2025-05-01

申请号：US18610737

申请日：2024-03-20

Applicant: Apple Inc.

Inventor： Van Luong PHAM ,  Arash VOSOUGHI ,  Dzung T. HOANG ,  Linfeng GUO ,  Alican NALCI ,  Guichun LI ,  Hilmi Enes EGILMEZ ,  Alexandros TOURAPIS

IPC: H04N19/117 ,  H04N19/14 ,  H04N19/176 ,  H04N19/196 ,  H04N19/82

Abstract: Low complexity, hardware-friendly techniques are proposed for video coding systems to mitigate banding artifacts while maintaining the compression efficiency. In general, the proposed techniques consist of two stages including a banding detection stage and a de-banding stage. The banding detection stage may identify the image/video regions where the banding artifact may be present based on gradient information and other information. The de-banding stage may apply corrective techniques to regions identified as likely to possess banding artifacts. In one embodiment, the de-banding adapts the filtering logic proposed by prior video coding standards for other filtering applications to mitigate banding. When implemented over the AV1 video coding standard and the AOM Video Model (AVM) reference software, the proposed technique improves subjective quality significantly at a reasonable hardware implementation cost. The methods and embodiments presented in this document can be beneficial find application in a wide variety of image/video coding standards and systems.

公开(公告)号：US20240129472A1

公开(公告)日：2024-04-18

申请号：US18468900

申请日：2023-09-18

Applicant: Apple Inc.

Inventor： Yeqing WU ,  Yunfei ZHENG ,  Alican NALCI ,  Yixin DU ,  Hilmi Enes EGILMEZ ,  Guoxin JIN ,  Alexandros TOURAPIS ,  Jun XIN ,  Hsi-Jung WU

IPC: H04N19/13 ,  H04N19/129 ,  H04N19/176

CPC classification number: H04N19/13 ,  H04N19/129 ,  H04N19/176

Abstract: Improved lossless entropy coding techniques for coding of image data include selecting a context for entropy coding based on an ordered scan path of possible context locations. A symbol for a current location within a source image may be entropy coded based on a context of prior encoded symbols of other locations within source images, where the context is selected based on an ordered scan path enumerating a series of potential context locations within one or more source images. To select a context, a predetermined number of prior symbols may be selected by qualifying or disqualifying locations in the scan path, and then the current symbol may be encoded with a context based on prior symbols corresponding to the first qualifying context locations in the order of the scan path.

公开(公告)号：US20240114128A1

公开(公告)日：2024-04-04

申请号：US18526481

申请日：2023-12-01

Applicant: Apple Inc.

Inventor： Alexandros TOURAPIS ,  Jungsun KIM ,  Krishnakanth RAPAKA ,  David William SINGER

IPC: H04N19/105 ,  H04N19/172 ,  H04N19/174 ,  H04N19/184 ,  H04N19/513 ,  H04N19/70

CPC classification number: H04N19/105 ,  H04N19/172 ,  H04N19/174 ,  H04N19/184 ,  H04N19/513 ,  H04N19/70

Abstract: Techniques for encoding video with motion compensation include a compressed bitstream syntax that includes a list of all motion prediction reference frames without distinguishing between short-term reference frame and long-term reference frames. The list of reference frames may be provided in a slice header and may apply to encoded data video data within the corresponding slice. The list may be prefaced with a single number indicating the total number of reference frames. In an aspect delta POC reference numbers may be encoded with a flag indicating the sign of the delta POC when the absolute value of the POC is not equal to zero. In another aspect, a flag may be encoded for every reference frame indicating if POC information should be used when scaling prediction references, and a weighting parameter may be included when POC information should be used.

公开(公告)号：US20230143147A1

公开(公告)日：2023-05-11

申请号：US17979027

申请日：2022-11-02

Applicant: Apple Inc.

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

IPC: H04N19/82 ,  H04N19/186 ,  H04N19/70

CPC classification number: H04N19/82 ,  H04N19/70 ,  H04N19/186

Abstract: A cross-component based filtering system is disclosed for video coders and decoders. The filtering system may include a filter having an input for a filter offset and an input for samples reconstructed from coded video data representing a native component of source video on which the filter operates. The offset may be generated at least in part from a sample classifier that classifies samples reconstructed from coded video data representing a color component of the source video orthogonal to the native component according to sample intensity.

公开(公告)号：US20210400273A1

公开(公告)日：2021-12-23

申请号：US17234596

申请日：2021-04-19

Applicant: Apple Inc.

Inventor： Krishnakanth RAPAKA ,  Jaehong CHON ,  Alexandros TOURAPIS ,  David W. SINGER

IPC: H04N19/124 ,  H04N19/82 ,  H04N19/186 ,  H04N19/172

Abstract: Improved video coding and decoding techniques are described, including techniques to derive quantization step sizes adaptively with quantization step size table templates. Quantization techniques described provide finer-grained control over quantization with a more flexible quantization step size especially at higher degrees of quantization. This may result in improved overall compression quality. Other coding parameters, such as in-loop filtering parameters, may be derived based on the more flexible quantization parameters.