CN-116567235-B - Image decoding device

Abstract

The invention provides an image decoding device. The complexity of encoding/decoding of moving images is reduced. The image decoding device (31) is provided with a CN information decoding unit (10) which divides the encoded nodes in a hierarchical manner by at least one of binary tree division and trigeminal tree division, and the CN information decoding unit restricts the division method of the target node by referring to the division method of a node immediately above the target node.

Inventors

• YASUGI YUKINOBU
• AONO TOMOKO
• IKAI TOMOHIRO

Assignees

• 夏普株式会社
• 鸿颖创新有限公司

Dates

Publication Date

20260512

Application Date

20171213

Priority Date

20161216

Claims (1)

1. 1. An image decoding device for decoding pictures for each coding tree unit, characterized in that, The image decoding device is provided with an encoding node CN information decoding unit which is configured to: Based on the width of the object node, the height of the object node, the 1 st minimum size, the 1 st maximum size and the hierarchy of the object node, performing binary tree BT segmentation possible judgment; When 1) the width or height of the object node is not less than the 1 st minimum size, 2) the width and height of the object node is not more than the 1 st maximum size, and 3) the hierarchy of the object node is smaller than a maximum hierarchy value, it is determined that BT segmentation, which is binary tree segmentation, is possible; Performing a trigeminal tree TT segmentation possible determination based on the width of the object node, the height of the object node, the 2 nd minimum size, the 2 nd maximum size, and the hierarchy of the object node; Determining that a three-tree division, TT division, is possible when 1) the width or height of the object node is not less than the 2 nd minimum size, 2) the width and height of the object node is not more than the 2 nd maximum size, and 3) the hierarchy of the object node is less than the maximum hierarchy value; determining whether decoding of a partition tree PT partition flag indicating whether the object node is partitioned by BT partition or TT partition is required; Decoding the PT split flag if the PT split flag needs to be decoded; when the PT split flag indicates that the target node is split by BT split or TT split, determining whether decoding of a split direction flag indicating a split direction is necessary; Decoding the division direction mark when the division direction mark needs to be decoded; determining whether decoding of a split mode selection flag indicating whether the split method is BT split or TT split is required; decoding the split mode selection flag if it is necessary to decode the split mode selection flag, and Dividing the object node of the code tree unit by BT division or TT division based on the division direction flag and the division mode selection flag, The CN information decoding unit further judges an additional condition that the BT segmentation is possible to judge, and when the target node is a node in the center among three nodes obtained by TT segmentation of a directly upper node, the CN information decoding unit prohibits segmentation of the target node by BT segmentation in the same direction as the direction in which the directly upper node is TT segmented, The CN information decoding section determines the BT split possibility determination based on the 1 st minimum size, and the CN information decoding section determines the TT split possibility determination based on the 2 nd minimum size, wherein the 2 nd minimum size is set to be 2 times as large as the 1 st minimum size.

Description

Image decoding device The present invention is a divisional application of an invention patent application having a filing date of 2017, 12, 13, 201780077762.3 and an invention name of "image decoding apparatus and image encoding apparatus". Technical Field Embodiments of the present invention relate to a predicted image generating apparatus, a moving image decoding apparatus, and a moving image encoding apparatus. Background In order to efficiently transmit or record a moving image, a moving image encoding device that generates encoded data by encoding a moving image, and a moving image decoding device that generates a decoded image by decoding the encoded data are utilized. Specific moving image coding methods include, for example, those proposed in h.264/AVC and HEVC (High-EFFICIENCY VIDEO CODING, high efficiency video coding). In such a moving image encoding system, an image (picture) constituting a moving image is managed by a hierarchical structure composed of a slice obtained by dividing the image, a Coding Unit (also referred to as Coding Unit: CU) obtained by dividing the slice, and a Prediction Unit (PU) and a Transform Unit (TU) which are blocks obtained by dividing the Coding Unit, and is encoded/decoded for each CU. In such a moving image encoding system, a prediction image is generally generated based on a locally decoded image obtained by encoding/decoding an input image, and a prediction residual (also referred to as a "differential image" or a "residual image") obtained by subtracting the prediction image from the input image (original image) is encoded. As a method for generating a predicted image, inter-picture prediction (inter-frame prediction) and intra-picture prediction (intra-frame prediction) are exemplified. Further, as a technique of encoding and decoding a moving image in recent years, non-patent documents 1 and 2 are cited. Prior art literature Non-patent literature Non-patent literature 1：″Algorithm Description of Joint Exploration Test Model 4″,JVET-D1001,Joint Video Exploration Team(JVET)0f ITU-T SG 16 WP 3and ISO/IEC JTC 1/SC 29/WG 11,15-21 October 2016 Non-patent literature 2：″Multi-Type-Tree″,JVET-D0117,Joint Video Exploration Team(JVET)of ITU-T SG 16 WP 3and ISO/IEC JTC 1/SC 29/WG 11,15-21October 2016 Disclosure of Invention Problems to be solved by the invention As a partition format of the encoding Node (CN: encoding Node), in non-patent document 2, BT (Binary Tree) partition and TT (TRIPLE TREE, trigeminal Tree) partition are introduced in addition to QT (Quad Tree) partition, and the partition pattern of the CU increases, and encoding/decoding becomes complicated. In addition, it is still not easy to realize a complicated division pattern, and further improvement is demanded in terms of improvement of coding efficiency. The present invention has been made in view of the above-described problems, and an object thereof is to provide an image decoding device and an image encoding device capable of reducing the complexity of encoding/decoding a moving image. Further, an image decoding device and an image encoding device are provided that can realize a more complex division pattern with less division depth. Means for solving the problems In order to solve the above-described problems, an image decoding apparatus according to an aspect of the present invention is an image decoding apparatus for decoding a picture for each code tree unit, the image decoding apparatus including a partition unit for hierarchically partitioning a code node of the code tree unit by at least one of binary tree partitioning and trigeminal tree partitioning, wherein the partition unit restricts a partition mode of a target node with reference to a partition mode of a node immediately above the target node. In the image decoding device according to an aspect of the present invention, the image decoding device decodes a picture for each code tree unit includes a dividing unit that divides the code nodes of the code tree unit in a hierarchical manner, and when the target node is rectangular with an aspect ratio equal to or greater than a predetermined value, the dividing unit restricts the dividing of the target node by three-tree division that generates a boundary along a longitudinal direction of the target node. An image decoding device according to an aspect of the present invention is an image decoding device for decoding a picture for each code tree unit, the image decoding device including a partition unit for hierarchically partitioning a code node of the code tree unit by at least one of binary tree partitioning and trigeminal tree partitioning, the partition unit limiting partitioning of a target node by referring to a depth variable common to the binary tree partitioning and the trigeminal tree partitioning. An image coding apparatus according to an aspect of the present invention is an image coding apparatus for coding a picture by dividing the picture into coding tree units, the image co