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：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：US20200084467A1

公开(公告)日：2020-03-12

申请号：US16125013

申请日：2018-09-07

Applicant: Apple Inc.

Inventor： Felix CHOU ,  Xiang FU ,  Linfeng GUO ,  Francesco IACOPINO ,  Qunxing YANG ,  Xiaohua YANG ,  Xu Gang ZHAO

IPC: H04N19/52 ,  H04N19/172 ,  H04N19/117 ,  H04N19/115 ,  H04N19/124 ,  H04N19/159

Abstract: Systems and methods are disclosed for improving the quality of a reconstructed video sequence that was captured under low light conditions by means of bitrate budget management. In response to a low illumination video capture detection, and based on estimation of the video image characteristics, frame bitrate budget and/or frame rate, used in motion compensated predictive coding techniques, are modified from their default values.

公开(公告)号：US20190246135A1

公开(公告)日：2019-08-08

申请号：US16222254

申请日：2018-12-17

Applicant: Apple Inc.

Inventor： Xiang FU ,  Xiaohua YANG ,  Linfeng GUO ,  Francesco IACOPINO ,  Felix CHOU ,  Ying Jian HE

IPC: H04N19/52 ,  H04N19/182 ,  H04N19/176 ,  H04N19/172

CPC classification number: H04N19/52 ,  H04N19/172 ,  H04N19/176 ,  H04N19/182

Abstract: Techniques for encoding video with reduced frame-boundary artifacts are presented. The techniques include a video encoding method, where, when skip mode is selected as a motion prediction coding mode for a pixel block predicted from a reference block of a reference frame, estimating an amount of the reference block that extends beyond the edge of the reference frame. If the amount beyond the edge does not exceed a threshold, the prediction may be coded with skip mode. If the amount beyond the edge exceeds a threshold, the pixel block may be partitioned, and the partitioned blocks may be coded with motion prediction.