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US-12627823-B2 - Image encoding/decoding method and apparatus for signaling information about number of DPB parameters, and computer-readable recording medium storing bitstream

US12627823B2US 12627823 B2US12627823 B2US 12627823B2US-12627823-B2

Abstract

Disclosed herein are an image encoding and decoding method and apparatus for signaling information on the number of DPB parameters, and a recording medium storing a bitstream. An image decoding method may comprise obtaining first information indicating the number of decoded picture buffer (DPB) parameter syntax structures in a video parameter set (VPS), computing the number of DPB parameter syntax structures in the VPS based on the first information, obtaining the DPB parameter syntax structures in the VPS based on the number of DPB parameter syntax structures, and managing a DPB based on the DPB parameter syntax structures.

Inventors

  • Seethal Paluri
  • Hendry Hendry
  • Seung Hwan Kim

Assignees

  • LG ELECTRONICS INC.

Dates

Publication Date
20260512
Application Date
20240912

Claims (10)

  1. 1 . An image decoding apparatus comprising: a memory; and at least one processor connected to the memory, the at least one processor configured to: obtain first information for deriving a number of decoded picture buffer (DPB) parameter syntax structures in a video parameter set (VPS); derive the number of DPB parameter syntax structures in the VPS based on the first information; obtain the DPB parameter syntax structures in the VPS based on the number of DPB parameter syntax structures; obtain an index for a DPB parameter syntax structure applied to an i-th multi-layer output layer set (OLS) based on whether the number of DPB parameter syntax structures is equal to a number of OLSs; and update a DPB based on the DPB parameter syntax structures, wherein the number of DPB parameter syntax structures in the VPS is derived by adding 1 to a value obtained by decoding the first information.
  2. 2 . The image decoding apparatus of claim 1 , wherein a value obtained by decoding the first information has a value equal to or greater than 0.
  3. 3 . The image decoding apparatus of claim 1 , wherein, when the first information is not present in a bitstream, the number of DPB parameter syntax structures in the VPS is set to 0.
  4. 4 . The image decoding apparatus of claim 1 , wherein, based on that the number of DPB parameter syntax structures is greater than 1, an index for the DPB parameter syntax structure applied to the i-th OLS is derived using index information obtained from a bitstream.
  5. 5 . The image decoding apparatus of claim 1 , wherein, based on that the number of DPB parameter syntax structures is equal to 1, an index for the DPB parameter syntax structure applied to the i-th OLS is derived to be equal to 0.
  6. 6 . The image decoding apparatus of claim 1 , wherein a value of the index information has a value equal to or greater than 0 and a maximum value of the index information is equal to a value of the first information.
  7. 7 . An image encoding apparatus comprising: a memory; and at least one processor connected to the memory, the at least one processor configured to: derive a value of first information based on the number of decoded picture buffer (DPB) parameter syntax structures in a video parameter set (VPS) and encoding the first information based on the derived value; encode the DPB parameter syntax structures in the VPS, based on the number of DPB parameter syntax structures; encode an index for a DPB parameter syntax structure applied to an i-th multi-layer output layer set (OLS) based on whether the number of DPB parameter syntax structures is equal to a number of OLSs; and update a DPB based on the DPB parameter syntax structures, wherein the first information is derived as a value obtained by subtracting 1 from the number of DPB parameter syntax structures in the VPS.
  8. 8 . The image encoding apparatus of claim 7 , wherein the derived value of the first information has a value equal to or greater than 0.
  9. 9 . The image encoding apparatus of claim 7 , wherein, when the number of DPB parameter syntax structures in the VPS is 0, encoding of the first information is skipped.
  10. 10 . An apparatus for transmitting a bitstream for an image, the apparatus comprising: at least one processor configured to generate the bitstream, the bitstream is generated by: deriving a value of first information based on the number of decoded picture buffer (DPB) parameter syntax structures in a video parameter set (VPS) and encoding the first information based on the derived value; encoding the DPB parameter syntax structures in the VPS, based on the number of DPB parameter syntax structures; encoding an index for a DPB parameter syntax structure applied to an i-th multi-layer output layer set (OLS) based on whether the number of DPB parameter syntax structures is equal to a number of OLSs; and updating a DPB based on the DPB parameter syntax structures, wherein the first information is derived as a value obtained by subtracting 1 from the number of DPB parameter syntax structures in the VPS, and a transmitter configured to transmit the bitstream.

Description

This application is a Continuation Application of U.S. patent application Ser. No. 17/915,302, filed on Sep. 28, 2022, now allowed, which is a National Stage of International Application No. PCT/KR2021/003878, filed on Mar. 29, 2021, which claims the benefit of U.S. Provisional Application No. 63,002,320, filed on Mar. 30, 2020, the contents of which are all hereby incorporated by reference herein in their entirety. TECHNICAL FIELD The present disclosure relates to an image encoding/decoding method and apparatus, and, more particularly, to an image encoding and decoding method and apparatus for signaling information on the number of decoded picture buffer (DPB) parameters, and a computer readable recording medium storing a bitstream generated by the image encoding method/apparatus of the present disclosure. 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 An object of the present disclosure is to provide an image encoding/decoding method and apparatus with improved encoding/decoding efficiency. Another object of the present disclosure is to provide an image encoding/decoding method and apparatus for improving encoding/decoding efficiency by efficiently signaling information on the number of DPB parameters. Another object of the present disclosure is to provide a method of transmitting a bitstream generated by an image encoding method or apparatus according to the present disclosure. Another object of the present disclosure is to provide a recording medium storing a bitstream generated by an image encoding method or apparatus according to the present disclosure. Another object of the present disclosure is to provide a recording medium storing a bitstream received, decoded and used to reconstruct an image by an image decoding apparatus according to the present disclosure. The technical problems solved by the present disclosure are not limited to the above technical problems and other technical problems which are not described herein will become apparent to those skilled in the art from the following description. Technical Solution An image decoding method performed by an image decoding apparatus according to an aspect of the present disclosure may comprise obtaining first information indicating the number of decoded picture buffer (DPB) parameter syntax structures in a video parameter set (VPS), computing the number of DPB parameter syntax structures in the VPS based on the first information, obtaining the DPB parameter syntax structures in the VPS based on the number of DPB parameter syntax structures, and managing a DPB based on the DPB parameter syntax structures. In the image decoding method of the present disclosure, the number of DPB parameter syntax structures in the VPS may be computed by adding 1 to a value obtained by decoding the first information. In the image decoding method of the present disclosure, a value obtained by decoding the first information may have a value equal to or greater than 0. In the image decoding method of the present disclosure, when the first information is not present in a bitstream, the number of DPB parameter syntax structures in the VPS may be set to 0. The image decoding method of the present disclosure may further comprise deriving an index for a DPB parameter syntax structure applied to an i-th OLS among output layer sets (OLSs) specified by the VPS, based on the computed number of DPB parameter syntax structures. In the image decoding method of the present disclosure, based on that the number of DPB parameter syntax structures is greater than 1, an index for the DPB parameter syntax structure applied to the i-th OLS may be derived using index information obtained from a bitstream. In the image decoding method of the present disclosure, based on that the number of DPB parameter syntax structures is equal to 1, an index for the DPB parameter syntax structure applied to the i-th OLS may be derived to be equal to 0. In the image decoding method of the present disclosure, a value of the index information may have a value equal to or greater than 0 and a maximum value of the index information may be equal to a value of the first information. An image decoding apparatus according to another aspect of the present disclosure may comprise a memory and at least one processor. The at least one processor may be configured to obtain first information indicating the