公开(公告)号：US20240163436A1

公开(公告)日：2024-05-16

申请号：US17988216

申请日：2022-11-16

Applicant: Apple Inc.

Inventor： Wei LI ,  Hye-Yeon CHEONG ,  Jiancong LUO ,  Linfeng GUO

IPC: H04N19/124 ,  H04N19/105 ,  H04N19/176 ,  H04N19/61

CPC classification number: H04N19/124 ,  H04N19/105 ,  H04N19/176 ,  H04N19/61

Abstract: Techniques are disclosed for achieving quantization in video coding applications that achieves high coding efficiency and retains high image quality. These techniques employ quantization processes using quantization parameters that have been developed according to Just Noticeable Difference (“JND”) models for estimating coding artifacts from video coding. According to these techniques, an input pixel block of video is predictively coded with reference to a prediction reference, and prediction residuals obtained therefrom are transformed to transform domain coefficients. A transform coefficient is quantized by a quantization parameter read from a table populated by JND-quality quantization values, which is indexed by a value representing a statistical analysis of the input pixel block.

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.