Coding method, decoding method, bitstream, coder, decoder and storage medium

{
  "publication_number": "US2026106969A1",
  "country": "US",
  "kind": "A1",
  "title": "Coding method, decoding method, bitstream, coder, decoder and storage medium",
  "abstract": "Provided are a coding method, a decoding method, a bitstream, a coder, a decoder and a storage medium. The method includes: determining a first BV parameter of a current block; on the basis of the first BV parameter, determining a first color-component reference sample and a second color-component reference sample which correspond to the current block, and based on the first color-component reference sample and the second color-component reference sample, establishing a mapping relationship between a first color component and a second color component; and based on the mapping relationship and a sample value of the first color component of the current block, determining a predicted value of the second color component of the current block. In this way, the accuracy of chroma prediction can be improved, the bit rate is reduced, and the codec efficiency can also be improved.",
  "claims": [
    "1. A decoding method, applied to a decoder, comprising: determining a first block vector (BV) parameter of a current block; determining a first color-component reference sample and a second color-component reference sample corresponding to the current block based on the first BV parameter, and establishing a mapping relationship between a first color component and a second color component based on the first color-component reference sample and the second color-component reference sample; and determining a predicted value of the second color component of the current block based on the mapping relationship and a sample value of the first color component of the current block. 2. The method of claim 1, wherein the determining a first BV parameter of a current block comprises: determining a first color component block of the current block; determining a second BV parameter of the first color component block when a prediction mode of the first color component block satisfies a first condition; and determining the first BV parameter of the current block based on the second BV parameter of the first color component block. 3. The method of claim 2, wherein the determining a first color component block of the current block comprises: determining a first color component region at a same position as the current block; and determining the first color component block of the current block from a plurality of blocks divided from the first color component region. 4. The method of claim 3, wherein the determining the first color component block of the current block from a plurality of blocks divided from the first color component region comprises: determining at least one candidate block at a preset position from the plurality of blocks divided from the first color component region; and determining the first color component block of the current block from the at least one candidate block. 5. The method of claim 2, further comprising: when the first color component block performs prediction based on a BV, determining whether the current block uses a target prediction mode; and in response to the current block using the target prediction mode, determining that the prediction mode of the first color component block satisfies the first condition. 6. The method of claim 2, wherein the determining the first BV parameter of the current block based on the second BV parameter of the first color component block comprises: constructing a BV parameter candidate list of the second color component of the current block based on the second BV parameter; and determining the first BV parameter of the current block based on the BV parameter candidate list. 7. The method of claim 6, wherein the constructing a BV parameter candidate list of the second color component of the current block based on the second BV parameter comprises: adjusting the second BV parameter to determine a candidate BV parameter of the second color component of the current block; and adding the candidate BV parameter to the BV parameter candidate list. 8. The method of claim 7, wherein the adjusting the second BV parameter to determine a candidate BV parameter of the second color component of the current block comprises: determining a preset sampling format for the current block; and scaling the second BV parameter according to the preset sampling format to determine the candidate BV parameter of the second color component of the current block. 9. The method of claim 6, wherein the determining the first BV parameter of the current block based on the BV parameter candidate list comprises: determining whether the BV parameter candidate list has one or more candidate BV parameters satisfying the first available condition; and in response to there being one or more candidate BV parameters satisfying the first available condition in the BV parameter candidate list, determining the first BV parameter of the current block based on the one or more candidate BV parameters. 10. The method of claim 9, wherein the determining the first BV parameter of the current block from the one or more candidate BV parameters comprises: in response to there being one candidate BV parameter satisfying the first available condition in the BV parameter candidate list, determining the one candidate BV parameter satisfying the first available condition as the first BV parameter; and in response to there being a plurality of candidate BV parameters satisfying the first available condition in the BV parameter candidate list, making a decision on the plurality of candidate BV parameters satisfying the first available condition to determine the first BV parameter. 11. The method of claim 10, wherein the making a decision on the plurality of candidate BV parameters satisfying the first available condition to determine the first BV parameter comprises: determining a first template for the current block; determining a first matching template for each of the plurality of candidate BV parameters based on the first template and the plurality of candidate BV parameters; when the first template and the first matching template satisfy a second condition, calculating a matching error between the first template of the current block and the first matching template according to a preset error criterion to determine a first cost value for each of the plurality of candidate BV parameters; and determining a minimum cost value from the first cost values of the plurality of candidate BV parameters, and determining a candidate BV parameter corresponding to the minimum cost value as the first BV parameter. 12. The method of claim 1, wherein the determining a first color-component reference sample and a second color-component reference sample corresponding to the current block based on the first BV parameter comprises: determining a position of the current block; scaling the position of the current block to determine a position of a first color component region at a same position of the current block, and scaling the first BV parameter to determine a third BV parameter of the first color component region at the same position as the current block; determining a reference block of the first color component based on the position of the first color component region and the third BV parameter, and determining the first color-component reference sample corresponding to the current block based on the reference block of the first color component; and determining a reference block of the second color component based on the position of the current block and the first BV parameter, and determining the second color-component reference sample corresponding to the current block based on the reference block of the second color component. 13. The method of claim 1, wherein the establishing a mapping relationship between a first color component and a second color component based on the first color-component reference sample and the second color-component reference sample comprises: determining a first look-up table based on the first color-component reference sample and the second color-component reference sample, wherein the first look-up table is used for recording a value of the second color component when an index key is the first color component. 14. The method of claim 1, wherein the establishing a mapping relationship between a first color component and a second color component based on the first color-component reference sample and the second color-component reference sample comprises: determining a first discrete model based on the first color-component reference sample and the second color-component reference sample, wherein the first discrete model is used to indicate the mapping relationship between the first color component and the second color component. 15. The method of claim 1, further comprising: determining a reconstructed pixel sample of a first color component region at a same position as the current block; and determining the sample value of the first color component of the current block based on the reconstructed pixel sample of the first color component region. 16. The method of claim 1, wherein the determining a predicted value of the second color component of the current block based on the mapping relationship and a sample value of the first color component of the current block comprises: in response to finding a value of the first color component equal to the sample value of the first color component in the mapping relationship, determining a value of the second color component corresponding to the value of the first color component as the predicted value of the second color component of the current block. 17. The method of claim 1, wherein the determining a predicted value of the second color component of the current block based on the mapping relationship and a sample value of the first color component of the current block comprises: determining a first initial predicted value of the second color component of the current block based on the mapping relationship and the sample value of the first color component of the current block; and performing a correction operation on the first initial predicted value to determine the predicted value of the second color component of the current block. 18. The method of claim 1, further comprising: determining a plurality of third initial predicted values of the second color component of the current block when the number of the first BV parameters is more than one; and performing a weighting calculation on the plurality of third initial predicted values to determine the predicted value of the second color component of the current block. 19. The method of claim 4, further comprising: when the first color component block of the current block comprises a plurality of candidate blocks, determining a second BV parameter for each of the plurality of candidate blocks; constructing a plurality of BV parameter candidate lists of the second color component of the current block based on the second BV parameters of the plurality of candidate blocks, and determining a plurality of first BV parameters of the second color component of the current block based on the plurality of BV parameter candidate lists; and establishing the mapping relationship between the first color component and the second color component based on the plurality of first BV parameters, and determining the predicted value of the second color component of the current block based on the mapping relationship and the sample value of the first color component of the current block. 20. A coding method, applied to a coder, comprising: determining a first block vector (BV) parameter of a current block; determining a first color-component reference sample and a second color-component reference sample corresponding to the current block based on the first BV parameter, and establishing a mapping relationship between a first color component and a second color component based on the first color-component reference sample and the second color-component reference sample; and determining a predicted value of the second color component of the current block based on the mapping relationship and a sample value of the first color component of the current block. 21. A non-transitory computer-readable storage medium, having a computer program and a bitstream stored, wherein the computer program, when executed by a processor, enables the processor to perform a coding method to generate the bitstream, wherein the coding method comprises: determining a first block vector (BV) parameter of a current block; determining a first color-component reference sample and a second color-component reference sample corresponding to the current block based on the first BV parameter, and establishing a mapping relationship between a first color component and a second color component based on the first color-component reference sample and the second color-component reference sample; and determining a predicted value of the second color component of the current block based on the mapping relationship and a sample value of the first color component of the current block."
  ],
  "description_excerpt": "The present disclosure relates to the technical field of video codec, and particularly relates to coding and decoding methods, a bitstream, a coder, a decoder, and a storage medium.\n\nWith people's increased demands for video display quality, new video application types such as high-definition video and ultra-high-definition video have emerged. The Joint Video Exploration Team (JVET) of the international standards organizations ISO/IEC and ITU-T has developed the video coding standard H.266/Versatile Video Coding (VVC). Among them, Intra block copy (IBC) is a block-level coding mode provided by VVC for video sequences of screen content types.\n\nIn the related art, for the Direct Mode (DM), if the IBC mode is used for a luma block, the setting of the chroma prediction mode in this scenario is unreasonable, resulting in inaccurate chroma prediction of the current block and degraded coding efficiency.\n\nThe present disclosure provides a coding and decoding method, a bitstream, a coder, a decoder, and a storage medium, which can improve the accuracy of chroma prediction, reduce the bit rate, and further improve the codec efficiency.",
  "cpc": [
    "H04N 19/105",
    "H04N 19/159",
    "H04N 19/176",
    "H04N 19/521"
  ],
  "ipc": [
    "H04N 19/105",
    "H04N 19/159",
    "H04N 19/176",
    "H04N 19/513"
  ],
  "assignees": [
    "Guangdong Oppo Mobile Telecommunications Corp Ltd"
  ],
  "inventors": [
    "Junyan Huo",
    "Yanzhuo Ma",
    "Fuzheng Yang",
    "Xue HAO",
    "Ming Li"
  ],
  "filing_date": "2025-12-16",
  "publication_date": "2026-04-16",
  "priority_date": "2023-07-04",
  "application_number": "US-202519421974-A",
  "family_id": "94171111",
  "cited_by_count": 0
}