公开(公告)号：US20180302621A1

公开(公告)日：2018-10-18

申请号：US15487853

申请日：2017-04-14

Applicant: Apple Inc.

Inventor： Xiang Fu ,  Xiaohua Yang ,  Linfeng Guo ,  Francesco Iacopino ,  Krishna Rapaka ,  Felix Chou ,  Mukta Gore

IPC: H04N19/124 ,  H04L29/06 ,  H04N19/105 ,  H04N19/117 ,  H04N19/176 ,  H04N19/61 ,  H04N19/85

CPC classification number: H04N19/124 ,  H04L65/4069 ,  H04L65/602 ,  H04L65/607 ,  H04N19/105 ,  H04N19/117 ,  H04N19/126 ,  H04N19/136 ,  H04N19/154 ,  H04N19/176 ,  H04N19/463 ,  H04N19/61 ,  H04N19/85

Abstract: Techniques are disclosed for developing quantization matrices for use in video coding. According to these techniques a first quantization matrix may be derived from a second quantization matrix by scaling quantization values of the second quantization matrix by scaling parameters. The scaling parameters may increase according to distance between each matrix position and a matrix origin, they may be derived from characteristics of a video sequence to be coded, or both. The first quantization matrix may be communicated to a decoder. Thereafter, a video sequence may be coded predictively. As part of the coding, pixel data of the video sequence may be transformed to a plurality of frequency domain coefficients, and the frequency domain coefficients may be quantized according to the first quantization matrix.

公开(公告)号：US10567768B2

公开(公告)日：2020-02-18

申请号：US15487853

申请日：2017-04-14

Applicant: Apple Inc.

Inventor： Xiang Fu ,  Xiaohua Yang ,  Linfeng Guo ,  Francesco Iacopino ,  Krishna Rapaka ,  Felix Chou ,  Mukta Gore

IPC: H04N19/124 ,  H04L29/06 ,  H04N19/105 ,  H04N19/117 ,  H04N19/176 ,  H04N19/61 ,  H04N19/85

Abstract: Techniques are disclosed for developing quantization matrices for use in video coding. According to these techniques a first quantization matrix may be derived from a second quantization matrix by scaling quantization values of the second quantization matrix by scaling parameters. The scaling parameters may increase according to distance between each matrix position and a matrix origin, they may be derived from characteristics of a video sequence to be coded, or both. The first quantization matrix may be communicated to a decoder. Thereafter, a video sequence may be coded predictively. As part of the coding, pixel data of the video sequence may be transformed to a plurality of frequency domain coefficients, and the frequency domain coefficients may be quantized according to the first quantization matrix.