EP-4742669-A2 - IMAGE PROCESSING DEVICE AND METHOD

Abstract

The present disclosure relates to an image processing apparatus and method capable of suppressing a reduction in encoding efficiency. An upper limit value of the number of bins allocated to a processing target subblock by distributing the number of bins among nonzero subblocks is set, a syntax element value regarding the processing target subblock is derived by using coefficient data derived from image data so that the number of bins does not exceed the upper limit value, and the syntax element value derived is encoded and coded data is generated. The present disclosure can be applied, for example, to an image processing apparatus, an image encode apparatus, an image decode apparatus, a transmitting apparatus, a receiving apparatus, a transmitting/receiving apparatus, an information processing apparatus, an imaging apparatus, a reproducing apparatus, an electronic device, an image processing method, an information processing method, and the like.

Inventors

• YAMATO, ATSUSHI
• TSUKUBA, TAKESHI

Assignees

• Sony Group Corporation

Dates

Publication Date

20260513

Application Date

20200206

Claims (6)

1. An method for transmitting a bitstream, the method comprising: (a) setting an upper limit value of a number of context-coded bins that can be allocated to a processing target block of an image, the processing target block comprising a plurality of sub-blocks, the upper limit value being determined on a basis of a size of the processing target block and a number of context-coded bins that can be allocated to each of the plurality of sub-blocks, wherein the size of the processing target block is greater than a size of each of the plurality of sub-blocks (b) selecting each one of the plurality of sub-blocks of the processing target block in turn, (c) deriving a syntax element value for each one of the selected sub-blocks in turn by using coefficient data derived from image data, such that a sum of a number of context coded bins used for encoding each of the syntax element values does not exceed the upper limit value; (d) encoding the derived syntax element values using arithmetic encoding (e) transmitting a bitstream comprising the encoded syntax element values.
2. The method according to claim 1, wherein the processing target block is a Coding Unit, CU, or a Transform Unit, TU.
3. The method according to claim 1, comprising setting the upper limit value based on a number of the plurality of sub-blocks in the processing target block and the number of context-coded bins that can be allocated to each of the plurality of sub-blocks.
4. An method for decoding a bitstream, the method comprising: (a) obtaining a bitstream comprising encoded syntax element values associated with a processing target block of an image, the processing target block comprising a plurality of sub-blocks; (b) decoding the encoded syntax element values to generate a syntax element value for each of the plurality of sub-blocks using arithmetic decoding, (c) setting an upper limit value of a number of context-coded bins that can be allocated to the processing target block on a basis of a size of the processing target block and a number of context-coded bins that can be allocated to each of the plurality of sub-blocks, wherein the size of the processing target block is greater than a size of each of the plurality of sub-blocks, (d) selecting each one of the plurality of sub-blocks of the processing target block in turn, and (e) deriving coefficient data corresponding to image data for each of the selected sub-blocks by using the generated syntax element values, wherein a sum of a number of context coded bins used for decoding each of the encoded syntax element values does not exceed the upper limit value.
5. The method according to claim 4, wherein the processing target block is a Coding Unit, CU, or a Transform Unit, TU.
6. The method according to claim 4, wherein comprising setting the upper limit value based on a number of the plurality of sub-blocks in the processing target block and the number of context-coded bins that can be allocated to each of the plurality of sub-blocks.

Description

TECHNICAL FIELD The present disclosure relates to an image processing apparatus and method, and particularly to an image processing apparatus and method capable of suppressing a reduction in encoding efficiency. BACKGROUND ART Conventionally, in CABAC for image encoding, the larger the number of context-coded bins when expressing a syntax element value, the better the encoding efficiency and the more a reduction in image quality can be suppressed. However, as the number of context-coded bins increases, the amount of processing increases. Therefore, a method of restricting the number of context-coded bins in units of subblock has been proposed (for example, Non-Patent Document 1). CITATION LIST NON-PATENT DOCUMENT Non-Patent Document 1: T.-D. Chuang, S.-T. Hsiang, Z.-Y. Lin, C.-Y. Chen, Y.-W. Huang, S.-M. Lei (MediaTek), "CE7(Tests 7.1, 7.2, 7.3, and 7.4):Constraints on context-coded bins for coefficient coding", JVET-M0173, Joint Video Exploration Team (JVET) of ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC 29/WG 11 13th Meeting: Marrakech, MA, 9-18 Jan 2019 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION However, in the case of this method, since the number of context-coded bins is uniformly restricted, the coefficient data cannot be increased or decreased locally according to the characteristics of the image, and there has been a possibility that the encoding efficiency is unnecessarily reduced. The present disclosure has been made in view of such circumstances and can suppress a reduction in encoding efficiency. SOLUTIONS TO PROBLEMS An image processing apparatus of an aspect of the present technology is an image processing apparatus including: a syntax element value derivation unit that sets an upper limit value of the number of bins allocated to a processing target subblock by distributing the number of bins among nonzero subblocks and derives a syntax element value regarding the processing target subblock by using coefficient data derived from image data so that the number of bins does not exceed the upper limit value; and an encode unit that encodes the syntax element value derived and generates coded data. An image processing method of an aspect of the present technology is an image processing method including: setting an upper limit value of the number of bins allocated to a processing target subblock by distributing the number of bins among nonzero subblocks and deriving a syntax element value regarding the processing target subblock by using coefficient data derived from image data so that the number of bins does not exceed the upper limit value; and encoding the syntax element value derived and generating coded data. An image processing apparatus of another aspect of the present technology is an image processing apparatus including: a decode unit that decodes coded data and generates a syntax element value; and a coefficient data derivation unit that sets an upper limit value of the number of bins allocated to a processing target subblock by distributing the number of bins among nonzero subblocks and derives coefficient data corresponding to image data regarding the processing target subblock by using the syntax element value generated so that the number of bins does not exceed the upper limit value. An image processing method of another aspect of the present technology is an image processing method including: decoding coded data and generating a syntax element value; and setting an upper limit value of the number of bins allocated to a processing target subblock by distributing the number of bins among nonzero subblocks and deriving coefficient data corresponding to image data regarding the processing target subblock by using the syntax element value generated so that the number of bins does not exceed the upper limit value. An image processing apparatus of yet another aspect of the present technology is an image processing apparatus including: a syntax element value derivation unit that sets an upper limit value of the number of bins allocated to a processing target subblock by distributing the number of bins allocated to a zero subblock to a nonzero subblock and derives a syntax element value regarding the processing target subblock by using coefficient data derived from image data so that the number of bins does not exceed the upper limit value; and an encode unit that encodes the syntax element value derived and generates coded data. An image processing method of yet another aspect of the present technology is an image processing method including: setting an upper limit value of the number of bins allocated to a processing target subblock by distributing the number of bins allocated to a zero subblock to a nonzero subblock and deriving a syntax element value regarding the processing target subblock by using coefficient data derived from image data so that the number of bins does not exceed the upper limit value; and encoding the syntax element value derived and generating coded data