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EP-4742665-A1 - IMAGE ENCODING/DECODING METHOD, RECORDING MEDIUM HAVING BITSTREAM STORED THEREIN, AND METHOD FOR TRANSMITTING BITSTREAM

EP4742665A1EP 4742665 A1EP4742665 A1EP 4742665A1EP-4742665-A1

Abstract

An image decoding method performed by an image decoding apparatus according to one aspect of the present disclosure may include obtaining a neural-network post-filter characteristics (NNPFC) supplemental enhancement information (SEI) message and a neural-network post-filter activation (NNPFA) SEI message; determining at least one neural-network to be used as a neural-network post-filter (NNPF) based on the NNPFC SEI message; and determining whether activating a target NNPF to be applied to a current picture or not based on the NNPFA SEI message, wherein the NNPFA SEI message includes target identification information and target base flag information, wherein the target NNPF is determined based on the target identification information and the target base flag information, wherein based on the target base flag information not indicating that the target NNPF is a base NNPF, there is at least one NNPFC SEI message, that precedes the NNPFA SEI message in decoding order, with indentification information equal to the target identification information and base flag information having a value equal to a value of the target base flag information.

Inventors

  • TAN, Hendry

Assignees

  • LG Electronics Inc.

Dates

Publication Date
20260513
Application Date
20240705

Claims (8)

  1. An image decoding method performed by an image decoding apparatus, the method comprising: obtaining a neural-network post-filter characteristics (NNPFC) supplemental enhancement information (SEI) message and a neural-network post-filter activation (NNPFA) SEI message; determining at least one neural-network to be used as a neural-network post-filter (NNPF) based on the NNPFC SEI message; and determining whether activating a target NNPF to be applied to a current picture or not based on the NNPFA SEI message, wherein the NNPFA SEI message includes target identification information and target base flag information, wherein the target NNPF is determined based on the target identification information and the target base flag information, wherein based on the target base flag information not indicating that the target NNPF is a base NNPF, there is at least one NNPFC SEI message, that precedes the NNPFA SEI message in decoding order, with indentification information equal to the target identification information and base flag information having a value equal to a value of the target base flag information.
  2. The image decoding method of claim 1, wherein the target base flag information having a value of 1 indicates that the target NNPF is the base NNPF with the identification information equal to the target identification information.
  3. The image decoding method of claim 1, wherein the target base flag information having a value of 0 indicates that the target NNPF is a NNPF specified by the NNPFC SEI message with the identification information equal to the target identification information, Wherein the NNPF SEI message with the identification information equal to the target identification information is a last NNPF SEI message that precedes a first VCL NAL unit of the current picture in decoding order and is not a repetition of the NNPFC SEI message that contains the base NNPF.
  4. An image encoding method performed by an encoding apparatus, the image encoding method comprising: encoding at least one neural-network that can be used as a post-processing filer into a neural-network post-filter characteristics (NNPFC) SEI message; and encoding whether a target NNPF that can be applied to the current picture is activated into a neural-network post-filter activation (NNPFA) SEI message, wherein the NNPFA SEI message includes target identification information and target base flag information, wherein based on the target base flag information not indicating that the target NNPF is a base NNPF, there is at least one NNPFC SEI message, that precedes the NNPFA SEI message in decoding order, with indentification information equal to the target identification information and base flag information having a value equal to a value of the target base flag information.
  5. The image encoding method of claim 4, wherein the target base flag information having a value of 1 indicates that the target NNPF is the base NNPF with the identification information equal to the target identification information.
  6. The image encoding method of claim 4, wherein the target base flag information having a value of 0 indicates that the target NNPF is a NNPF specified by the NNPFC SEI message with the identification information equal to the target identification information, Wherein the NNPF SEI message with the identification information equal to the target identification information is a last NNPF SEI message that precedes a first VCL NAL unit of the current picture in decoding order and is not a repetition of the NNPFC SEI message that contains the base NNPF.
  7. A computer-readable digital storage medium for storing a bitstream generated using an image encoding method, the bitstream comprising: a neural-network post-filter characteristics (NNPFC) SEI message indicating at least one neural-network that can be used as a post-processing filer; and a neural-network post-filter activation (NNPFA) SEI message indicating whether a target NNPF that can be applied to the current picture is activated, wherein the NNPFA SEI message includes target identification information and target base flag information, wherein based on the target base flag information not indicating that the target NNPF is a base NNPF, there is at least one NNPFC SEI message, that precedes the NNPFA SEI message in decoding order, with indentification information equal to the target identification information and base flag information having a value equal to a value of the target base flag information.
  8. A method of transmitting data of an image, the method comprising: generating a bitstream of the image, the bitstream is generated by encoding at least one neural-network that can be used as a post-processing filer into a neural-network post-filter characteristics (NNPFC) SEI message and encoding whether a target NNPF that can be applied to the current picture is activated into a neural-network post-filter activation (NNPFA) SEI message; and transmitting the data including the bitstream, wherein the NNPFA SEI message includes target identification information and target base flag information, wherein based on the target base flag information not indicating that the target NNPF is a base NNPF, there is at least one NNPFC SEI message, that precedes the NNPFA SEI message in decoding order, with indentification information equal to the target identification information and base flag information having a value equal to a value of the target base flag information.

Description

[Technical Field] The present disclosure relates to an image decoding method, an image encoding method, and a method of transmitting a bitstream, and to a method of determining whether to activate a neural network post filter. [Background Art] Recently, demand for high-resolution and high-quality images such as high definition (HD) images and ultra high definition (UHD) images is increasing in various fields. As resolution and quality of image data are improved, the amount of transmitted information or bits relatively increases as compared to existing image data. An increase in the amount of transmitted information or bits causes an increase in transmission cost and storage cost. Accordingly, there is a need for high-efficient image compression technology for effectively transmitting, storing and reproducing information on high-resolution and high-quality images. [Disclosure] [Technical Problem] The present disclosure is directed to providing an image encoding/decoding method and apparatus with improved encoding/decoding efficiency. The present disclosure is also directed to providing a method of clearly determining a filter to be activated between a base filter and an updated filter. The present disclosure is also directed to providing a method of preventing occurrence of a situation where it is unclear whether to activate a base filter or an updated filter. The present disclosure is also directed to providing a non-transitory computer-readable recording medium for storing a bitstream generated using an image encoding method according to the present disclosure. The present disclosure is also directed to providing a non-transitory computer-readable recording medium for storing a bitstream that is received and decoded by an image decoding apparatus according to the present disclosure and used for image reconstruction. The present disclosure is also directed to providing a method of transmitting a bitstream generated using an image encoding method according to the present disclosure. Technical objects of the present disclosure are not limited to those described above, and other technical objects that have not been described above will be clearly understood by those skilled in the technical field to which the present disclosure pertains from the following description. [Technical Solution] An image decoding method performed by an image decoding apparatus according to one aspect of the present disclosure may include obtaining a neural-network post-filter characteristics (NNPFC) supplemental enhancement information (SEI) message and a neural-network post-filter activation (NNPFA) SEI message; determining at least one neural-network to be used as a neural-network post-filter (NNPF) based on the NNPFC SEI message; and determining whether activating a target NNPF to be applied to a current picture or not based on the NNPFA SEI message, wherein the NNPFA SEI message includes target identification information and target base flag information, wherein the target NNPF is determined based on the target identification information and the target base flag information, wherein based on the target base flag information not indicating that the target NNPF is a base NNPF, there is at least one NNPFC SEI message, that precedes the NNPFA SEI message in decoding order, with indentification information equal to the target identification information and base flag information having a value equal to a value of the target base flag information. An image encoding method performed by an image encoding apparatus according to one aspect of the present disclosure may include encoding at least one neural-network that can be used as a post-processing filer into a neural-network post-filter characteristics (NNPFC) SEI message; and encoding whether a target NNPF that can be applied to the current picture is activated into a neural-network post-filter activation (NNPFA) SEI message, wherein the NNPFA SEI message includes target identification information and target base flag information, wherein based on the target base flag information not indicating that the target NNPF is a base NNPF, there is at least one NNPFC SEI message, that precedes the NNPFA SEI message in decoding order, with indentification information equal to the target identification information and base flag information having a value equal to a value of the target base flag information. A computer-readable digital storage medium according to one aspect of the present disclosure may store bitstream generated by the image encoding method or the image encoding apparatus. A transmitting method according to one aspect of the present disclosure may transmit bitstream generated by the image encoding method or the image encoding apparatus. The features of the present disclosure briefly summarized above are merely illustrative aspects of the detailed description of the present disclosure and do not limit the scope of the present disclosure. [Advantageous Effects] According to the prese