EP-4742664-A1 - IMAGE ENCODING/DECODING METHOD, RECORDING MEDIUM STORING BITSTREAM, AND METHOD OF TRANSMITTING BITSTREAM

Abstract

Disclosed herein are an image decoding/encoding method, a storage medium storing a bitstream and a method for transmitting a bitstream. According to an aspect of the present disclosure, an image decoding method include obtaining a NNPF SEI message, the NNPF SEI message including a NNPFC SEI message and a NNPFA SEI message, determining a neural-network that can be used as a post-processing filer based on the NNPFC SEI message, and determining whether to activate a target NNPF that can be applied to the current picture based on the NNPFA SEI message, wherein the target NNPF is used for post-processing filtering for the current picture and subsequent pictures of a current layer in output order until a picture in a current layer associated with an NNPFA SEI message with the same target NNPF ID information as a current SEI message is output that follows the current picture in the output order.

Inventors

• TAN, Hendry

Assignees

• LG Electronics Inc.

Dates

Publication Date

20260513

Application Date

20240705

Claims (12)

1. An image decoding method performed by a decoding apparatus, the image decoding method comprising: obtaining neural-network post-filter (NNPF) supplemental enhancement information (SEI) message, the NNPF SEI message including a neural-network post-filter characteristics (NNPFC) SEI message and a neural-network post-filter activation (NNPFA) SEI message; determining a neural-network that can be used as a post-processing filer based on the NNPFC SEI message; and determining whether to activate a target NNPF that can be applied to the current picture based on the NNPFA SEI message, wherein the target NNPF is used for post-processing filtering for the current picture and subsequent pictures of a current layer in output order until a picture in a current layer associated with an NNPFA SEI message with the same target NNPF ID information as a current SEI message is output that follows the current picture in the output order.
2. The image decoding method of claim 1, wherein the determining whether to activate the target NNPF comprises: determining the target NNPF; determining whether to cancel a persistence of the target NNPF; and determining the persistence of the target NNPF based on not canceling the persistence of the target NNPF.
3. The image decoding method of claim 1, wherein the target NNPF is determined based on target NNPF ID information indicating the target NNPF specified by one or more NNPFC SEI messages that pertain to the current picture and have the same NNPF ID information as the NNPFA SEI message.
4. The image decoding method of claim 2, whether to cancel the persistence of the target NNPF is determined based on a persistence cancellation flag indicating whether to cancel the persistence of a target NNPF established by a previous NNPFA SEI message with the same target NNPF ID information as the current SEI message.
5. The image decoding method of claim 2, wherein the persistence of the target NNPF is determined based on whether the picture in the current layer is output that follows the current picture in the output order regardless of a value of a persistence cancellation flag included in the NNPFA SEI message associated with the picture in the current layer.
6. An image encoding method performed by an encoding apparatus, the image encoding method comprising: encoding a neural-network that can be used as a post-processing filer into a neural-network post-filter characteristics (NNPFC) SEI message included in the NNPF SEI message; and encoding whether a target NNPF that can be applied to the current picture is activated with a neural-network post-filter activation (NNPFA) SEI message included in the NNPF SEI message, wherein the target NNPF is used for post-processing filtering for the current picture and subsequent pictures of a current layer in output order until a picture in a current layer associated with an NNPFA SEI message with the same target NNPF ID information as a current SEI message is output that follows the current picture in the output order.
7. The image encoding method of claim 6, whether to activate the target NNPF is determined based on determining the target NNPF, determining whether to cancel a persistence of the target NNPF and determining the persistence of the target NNPF based on not canceling the persistence of the target NNPF.
8. The image encoding method of claim 6, wherein the target NNPF is determined based on target NNPF ID information indicating the target NNPF specified by one or more NNPFC SEI messages that pertain to the current picture and have the same NNPF ID information as the NNPFA SEI message.
9. The image encoding method of claim 7, whether to cancel the persistence of the target NNPF is determined based on a persistence cancellation flag indicating whether to cancel the persistence of a target NNPF established by a previous NNPFA SEI message with the same target NNPF ID information as the current SEI message.
10. The image encoding method of claim 7, wherein the persistence of the target NNPF is determined based on whether the picture in the current layer is output that follows the current picture in the output order regardless of a value of a persistence cancellation flag included in the NNPFA SEI message associated with the picture in the current layer.
11. 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 a 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 target NNPF is used for post-processing filtering for the current picture and subsequent pictures of a current layer in output order until a picture in a current layer associated with an NNPFA SEI message with the same target NNPF ID information as a current SEI message is output that follows the current picture in the output order.
12. A method of transmitting data of an image, the method comprising: generating a bitstream of the image, the bitstream is generated by encoding a neural-network that can be used as a post-processing filer into a neural-network post-filter characteristics (NNPFC) SEI message included in the NNPF SEI message and encoding whether a target NNPF that can be applied to the current picture is activated with a neural-network post-filter activation (NNPFA) SEI message included in the NNPF SEI message, and transmitting the data including the bitstream, wherein the target NNPF is used for post-processing filtering for the current picture and subsequent pictures of a current layer in output order until a picture in a current layer associated with an NNPFA SEI message with the same target NNPF ID information as a current SEI message is output that follows the current picture in the output order.

Description

BACKGROUND 1. Field The present disclosure relates to an image encoding/decoding method, a recording medium storing a bitstream, and a method of transmitting a bitstream, and more particularly, to a method of determining whether to cancel the persistence of a neural network post-filter (NNPF). 2. Description of the Related 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. SUMMARY 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 which neural network post-filter (NNPF)'s persistence should be cancelled when there is activation of two or more NNPFs with the same identification information. The present disclosure is also directed to providing a method of preventing simultaneous activation of two or more NNPFs with the same identification information. 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 method of transmitting 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 which is received and decoded by an image decoding apparatus according to the present disclosure and used for reconstructing an image. 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. According to an aspect of the present disclosure, an image decoding method performed by a decoding apparatus may include obtaining neural-network post-filter (NNPF) supplemental enhancement information (SEI) message, the NNPF SEI message including a neural-network post-filter characteristics (NNPFC) SEI message and a neural-network post-filter activation (NNPFA) SEI message, determining a neural-network that can be used as a post-processing filer based on the NNPFC SEI message, and determining whether to activate a target NNPF that can be applied to the current picture based on the NNPFA SEI message, wherein the target NNPF is used for post-processing filtering for the current picture and subsequent pictures of a current layer in output order until a picture in a current layer associated with an NNPFA SEI message with the same target NNPF ID information as a current SEI message is output that follows the current picture in the output order. According to an aspect of the present disclosure, an image encoding method performed by an encoding apparatus may include encoding a neural-network that can be used as a post-processing filer into a neural-network post-filter characteristics (NNPFC) SEI message included in the NNPF SEI message, and encoding whether a target NNPF that can be applied to the current picture is activated with a neural-network post-filter activation (NNPFA) SEI message included in the NNPF SEI message, wherein the target NNPF is used for post-processing filtering for the current picture and subsequent pictures of a current layer in output order until a picture in a current layer associated with an NNPFA SEI message with the same target NNPF ID information as a current SEI message is output that follows the current picture in the output order. A computer-readable recording medium according to another aspect of the present disclosure can store a bitstream generated by an image encoding method or device of the present disclosure. A transmission method according to another aspect of the present disclosure can transmit a bitstream generated by an image encoding method or device of the present disclosure. 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. According to the present disclosure, it is possible to provide an image encoding/decoding method and apparatus with improved encoding/decoding efficiency. According to the present disclosure, it is