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US-20260129224-A1 - METHOD, APPARATUS, AND MEDIUM FOR VIDEO PROCESSING

US20260129224A1US 20260129224 A1US20260129224 A1US 20260129224A1US-20260129224-A1

Abstract

Embodiments of the disclosure provide a solution for video processing. A method for video processing is proposed. The method includes: deriving, for a conversion between a video unit of a video and a bitstream of the video, a refined prediction sample of a prediction sample in the video unit by applying a function to the prediction sample, wherein the function comprises one or more parameters; and performing the conversion based on the refined prediction sample.

Inventors

  • Yang Wang
  • Kai Zhang
  • Yuwen He
  • Hongbin Liu
  • Li Zhang

Assignees

  • Douyin Vision Co., Ltd.
  • BYTEDANCE INC.

Dates

Publication Date
20260507
Application Date
20251229
Priority Date
20230629

Claims (20)

  1. 1 . A method for video processing, comprising: deriving, for a conversion between a video unit of a video and a bitstream of the video, a refined prediction sample of a prediction sample in the video unit by applying a function to the prediction sample, wherein the function comprises one or more parameters; and performing the conversion based on the refined prediction sample.
  2. 2 . The method of claim 1 , wherein the function is a linear model used in local illumination compensation (LIC).
  3. 3 . The method of claim 1 , wherein the function is a linear equation.
  4. 4 . The method of claim 3 , wherein the function is represented as: f(p[x, y])=α*p[x, y]+β, and wherein α and β represents parameters of the linear equation.
  5. 5 . The method of claim 1 , wherein an approach is applied to derive the one or more parameters of the function using a set of training samples by minimizing a difference between a ground truth and a prediction of the set of training samples.
  6. 6 . The method of claim 5 , wherein the ground truth comprises a reconstruction of the video unit and the prediction comprises one or more prediction signals of the video unit, and/or wherein the ground truth comprises a prediction or reconstruction of luma video unit and the prediction comprises a prediction or reconstruction of chroma video unit, and/or wherein a Least-Mean-Square (LMS) approach is used to derive the one or more parameters of the function, and/or wherein an LDL approach is used to derive the one or more parameters of the function, and/or wherein a Gaussian elimination is used to derive the one or more parameters of the function.
  7. 7 . The method of claim 6 , wherein the Gaussian elimination comprises an approach used in convolutional cross-component model (CCCM).
  8. 8 . The method of claim 7 , wherein the one or more parameters of the function are modified using adjustment parameters.
  9. 9 . The method of claim 8 , wherein the one or more parameters of the function comprise α and β, and an adjustment parameter is used to adjust α, and/or wherein at least one of: a slope adjustment parameter or an indication of the slope adjustment parameter is signalled in the bitstream, and/or wherein at least one of: the adjustment parameters or the indication of the adjustment parameters is derived using coding information, and/or wherein the number of adjustment parameters are predefined or signalled or derived, and the number of the adjustment parameters is an integer larger than 0, and/or wherein at least one of: the adjustment parameters or an indication of the adjustment parameters is inherited, and/or wherein an adjustment parameter is used to adjust more than one parameters of the function, and/or wherein a reordering approach is applied during signalling and/or deriving a slope adjustment parameter.
  10. 10 . The method of claim 9 , wherein an adjusted parameter of the function is α+u or α×u, and/or wherein a sign and an absolute value of the slope adjustment parameter are signalled using one or more syntax elements.
  11. 11 . The method of claim 10 , wherein the one or more syntax elements are binarized with one of: fixed length coding, truncated unary coding, unary coding, EG coding, or coded a flag, and/or wherein the one or more syntax elements are bypass coded or context coded, and/or wherein a pre-defined absolute value is used and is not signalled, and/or wherein the absolute value is equal to 1 or 2 or 3 or 4, and/or wherein the number of adjustment parameters is equal to 1 or 2 or 3 or 4 or 6 or 8, and/or wherein the one or more parameters of the function comprise α and β, and wherein α′=α+u and β′=β−u*m, wherein u re the adjustment parameter and m represents a variable which is derived using samples that are used to derive the one or more parameters of the function, and/or wherein a unit of the slope adjustment parameter is 1/Nth of a chroma sample value per one luma sample value, wherein N is an integer number, and/or wherein the slope adjustment parameter is an integer number which is not equal to zero.
  12. 12 . The method of claim 11 , wherein m is calculated depending on the samples that are used to derive local illumination compensation (LIC) parameters, and/or wherein m is equal to mean of the samples, and/or wherein N is equal to 2, or 4, or 8, or 16, or 32, and/or wherein the slope adjustment parameter is in a range between T1 and T2.
  13. 13 . The method of claim 9 , wherein a template of the video unit comprising neighbouring reconstructed samples is used in the reordering approach and wherein a template size is a constant value or an adaptive value depending on block dimensions or block size.
  14. 14 . The method of claim 13 , wherein the constant value is one of: 1, 2, or 4.
  15. 15 . The method of claim 1 , wherein at least one of: a slope adjustment parameter or LIC parameter of the video unit is used by following video units.
  16. 16 . The method of claim 15 , wherein the LIC parameter of the video unit comprises one or more parameters used to refine the prediction for the video unit, and/or wherein the LIC parameter of the video unit is derived using a template, and/or wherein the LIC parameter of the video unit is derived using the prediction and reconstruction of the video unit, and/or wherein the slope adjustment parameter and/or LIC parameter are stored in a history table, and/or wherein the slope adjustment parameter and/or LIC parameter are used by the following at least one of: spatial adjacent or non-adjacent neighbouring video units, and/or wherein the slope adjustment parameter and/or LIC parameter are used by the following video units in one of: a same coding tree unit (CTU), a same CTU row, a same slice, a same tile, or a same picture, and/or wherein the slope adjustment parameter and/or LIC parameter are used by the following video units in one of: a different CTU, a different CTU row, a different slice, a different tile or a different picture, and/or wherein slope adjustment parameter and/or LIC parameter of a luma video unit are used for a chroma video unit, and/or wherein one or more parameters of the function are modified if the slope adjustment parameter and/or LIC parameter are used for the following video units.
  17. 17 . The method of claim 1 , wherein the conversion includes encoding the video unit into the bitstream, and/or wherein the conversion includes decoding the video unit from the bitstream.
  18. 18 . An apparatus for video processing comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to perform acts comprising: deriving, for a conversion between a video unit of a video and a bitstream of the video, a refined prediction sample of a prediction sample in the video unit by applying a function to the prediction sample, wherein the function comprises one or more parameters; and performing the conversion based on the refined prediction sample.
  19. 19 . A non-transitory computer-readable storage medium storing instructions that cause a processor to perform acts comprising: deriving, for a conversion between a video unit of a video and a bitstream of the video, a refined prediction sample of a prediction sample in the video unit by applying a function to the prediction sample, wherein the function comprises one or more parameters; and performing the conversion based on the refined prediction sample.
  20. 20 . A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by an apparatus for video processing, wherein the method comprises: deriving a refined prediction sample of a prediction sample in a video unit of the video by applying a function to the prediction sample, wherein the function comprises one or more parameters; and generating the bitstream of the video unit based on the refined prediction sample.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of International Application No. PCT/CN2024/102063, filed on Jun. 27, 2024, which claims the benefits of International Application No. PCT/CN2023/103830, filed on Jun. 29, 2023, International Application No. PCT/CN2023/124102, filed on Oct. 11, 2023, International Application No. PCT/CN2023/138564, filed on Dec. 13, 2023. The entire contents of these applications are hereby incorporated by reference in their entireties. FIELDS Embodiments of the present disclosure relates generally to video processing techniques, and more particularly, to local illumination compensation with slope adjustment. BACKGROUND In nowadays, digital video capabilities are being applied in various aspects of peoples' lives. Multiple types of video compression technologies, such as MPEG-2, MPEG-4, ITU-TH.263, ITU-TH.264/MPEG-4 Part 10 Advanced Video Coding (AVC), ITU-TH.265 high efficiency video coding (HEVC) standard, versatile video coding (VVC) standard, have been proposed for video encoding/decoding. However, coding efficiency of video coding techniques is generally expected to be further improved. SUMMARY Embodiments of the present disclosure provide a solution for video processing. In a first aspect, a method for video processing is proposed. The method comprises: deriving, for a conversion between a video unit of a video and a bitstream of the video, a refined prediction sample of a prediction sample in the video unit by applying a function to the prediction sample, wherein the function comprises one or more parameters; and performing the conversion based on the refined prediction sample. In this way, coding performance can be improved by adjusting the parameters. In a second aspect, an apparatus for video processing is proposed. The apparatus comprises a processor and a non-transitory memory with instructions thereon. The instructions upon execution by the processor, cause the processor to perform a method in accordance with the first aspect of the present disclosure. In a third aspect, a non-transitory computer-readable storage medium is proposed. The non-transitory computer-readable storage medium stores instructions that cause a processor to perform a method in accordance with the first aspect of the present disclosure. In a fourth aspect, another non-transitory computer-readable recording medium is proposed. The non-transitory computer-readable recording medium stores a bitstream of a video which is generated by a method performed by an apparatus for video processing. The method comprises: deriving a refined prediction sample of a prediction sample in a video unit of the video by applying a function to the prediction sample, wherein the function comprises one or more parameters; and generating the bitstream of the video unit based on the refined prediction sample. In a fifth aspect, a method for storing a bitstream of a video is proposed. The method comprises: deriving a refined prediction sample of a prediction sample in a video unit of the video by applying a function to the prediction sample, wherein the function comprises one or more parameters; generating the bitstream of the video unit based on the refined prediction sample; and storing the bitstream in a non-transitory computer-readable recording medium. This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS Through the following detailed description with reference to the accompanying drawings, the above and other objectives, features, and advantages of example embodiments of the present disclosure will become more apparent. In the example embodiments of the present disclosure, the same reference numerals usually refer to the same components. FIG. 1 illustrates a block diagram that illustrates an example video coding system, in accordance with some embodiments of the present disclosure; FIG. 2 illustrates a block diagram that illustrates a first example video encoder, in accordance with some embodiments of the present disclosure; FIG. 3 illustrates a block diagram that illustrates an example video decoder, in accordance with some embodiments of the present disclosure; FIG. 4 illustrates an example of encoder block diagram; FIG. 5 illustrates 67 intra prediction modes; FIG. 6A and FIG. 6B illustrate reference samples for wide-angular intra prediction, respectively; FIG. 7 illustrates problem of discontinuity in case of directions beyond 45°; FIG. 8A and FIG. 8B illustrate MMVD Search Point; FIG. 9 illustrates an illustration for symmetrical MVD mode; FIG. 10 illustrates extended CU region used in BDOF; FIG. 11 illustrates top and left neighboring blocks used in CIIP weight derivation; FIG