公开(公告)号：US20250080759A1

公开(公告)日：2025-03-06

申请号：US18794601

申请日：2024-08-05

Applicant: APPLE INC.

Inventor： Guoxin JIN ,  Yeqing WU ,  Yunfei ZHENG ,  Dazhong ZHANG ,  Dzung T. HOANG ,  Felix C. FERNANDES ,  Van Luong PHAM ,  Jiancong LUO ,  Yixin DU ,  Hilmi Enes EGILMEZ ,  Alican NALCI ,  Jun XIN ,  Hsi-Jung WU

IPC: H04N19/176 ,  H04N19/117 ,  H04N19/159 ,  H04N19/46 ,  H04N19/70 ,  H04N19/82

Abstract: Techniques are disclosed for coding video in applications where regions of video are inactive on a frame to frame basis. According to the techniques, coding processes update and reconstruct only a subset of pixel blocks of pixels within a frame, while other pixel blocks are retained from a previously coded frame stored in a coder's or decoder's reference frame buffer. The technique is called Backward Reference Updating (or “BRU”) for convenience. At a desired pixel block granularity, based on the activity between a current frame to be coded and its reference frame(s), BRU will only perform prediction, transform, quantization, and reconstruction on selected regions that are determined to be active. The reconstructed pixels in these active regions are directly placed onto a specified reference frame in memory instead of creating a new frame. Therefore, fewer memory transfers need to be performed.

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.