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EP-4740456-A1 - METHODS AND APPARATUS FOR VIDEO CODING IMPROVEMENT BY MODEL DERIVATION

EP4740456A1EP 4740456 A1EP4740456 A1EP 4740456A1EP-4740456-A1

Abstract

A method and apparatus for coding colour pictures or video using coding tools including one or more cross component models related modes are disclosed. According to this method, a target cross-component candidate is determined among at least one of one or more self-derived cross-component candidates and one or more inherited candidates. In response to said one or more self-derived cross-component candidates being determined as the target cross-component candidate, one or more models based on said one or more self-derived cross-component candidates determined are derived. In response to said one or more inherited candidates being selected as the target cross-component candidate, one or more models based on said one or more inherited candidates determined are determined. The second-colour block is encoded or decoded by using target prediction generated according to the target cross-component candidate.

Inventors

  • CHIANG, Man-Shu
  • TSENG, HSIN-YI
  • TSAI, CHIA-MING
  • CHUANG, CHENG-YEN
  • HSU, CHIH-WEI
  • CHEN, YI-WEN

Assignees

  • MEDIATEK INC.

Dates

Publication Date
20260513
Application Date
20240705

Claims (15)

  1. A method of coding colour pictures or video using coding tools including one or more cross component models related modes, the method comprising: receiving input data associated with a current block comprising a first-colour block and a second-colour block, wherein the input data comprise pixel data to be encoded at an encoder side or data associated with the current block to be decoded at a decoder side, and wherein the current block is coded in a non-intra mode; determining a target cross-component candidate among at least one of one or more self-derived cross-component candidates and one or more inherited candidates, wherein: in response to said one or more self-derived cross-component candidates being determined as the target cross-component candidate, deriving one or more models based on said one or more self-derived cross-component candidates determined; or in response to said one or more inherited candidates being determined as the target cross-component candidate, determining one or more models based on said one or more inherited candidates determined; and encoding or decoding the second-colour block by using target prediction generated according to the target cross-component candidate.
  2. The method of Claim 1, wherein said one or more self-derived cross-component candidates comprise Cross-Component Residual Model (CCRM) .
  3. The method of Claim 1, wherein said one or more self-derived cross-component candidates, said one or more inherited candidates, or both are added into a candidate list and selected from the candidate list.
  4. The method of Claim 3, wherein said one or more self-derived cross-component candidates are added to the candidate list only when the candidate list contains not enough inherited candidates.
  5. The method of Claim 3, wherein said one or more self-derived cross-component candidates are added to the candidate list before any default candidate.
  6. The method of Claim 3, wherein said one or more self-derived cross-component candidates are treated as one or more default candidates for the candidate list.
  7. The method of Claim 3, wherein said one or more self-derived cross-component candidates are added to the candidate list in one or more pre-defined positions.
  8. The method of Claim 3, wherein a flag is signalled or parsed to indicate enabling or disabling of said one or more self-derived cross-component candidates for generation or exclusion in the candidate list.
  9. The method of Claim 3, wherein enabling or disabling of said one or more self-derived cross-component candidates for generation or exclusion in the candidate list is based on one or more implicit rules.
  10. The method of Claim 3, wherein member candidates in the candidate list are reordered.
  11. The method of Claim 10, wherein the member candidates in the candidate list are reordered according to model errors associated with the member candidates evaluated on one or more neighbouring templates.
  12. The method of Claim 11, wherein each of the model errors is derived based on predicted samples in said one or more neighbouring templates using a model associated with each of the member candidates and reconstructed samples in said one or more neighbouring templates.
  13. The method of Claim 1, wherein a flag is signalled or parsed to indicate or select the target cross-component candidate being selected from said one or more self-derived cross-component candidates or from said one or more inherited candidates.
  14. The method of Claim 1, wherein the target cross-component candidate being selected from said one or more self-derived cross-component candidates or from said one or more inherited candidates is based on one or more implicit rules.
  15. An apparatus for coding colour pictures or video using coding tools including one or more cross component models related modes, the apparatus comprising one or more electronic circuits or processors arranged to: receive input data associated with a current block comprising a first-colour block and a second-colour block, wherein the input data comprise pixel data to be encoded at an encoder side or data associated with the current block to be decoded at a decoder side, and wherein the current block is coded in a non-intra mode; determine a target cross-component candidate among at least one of one or more self-derived cross-component candidates and one or more inherited candidates, wherein: in response to said one or more self-derived cross-component candidates being determined as the target cross-component candidate, derive one or more models based on said one or more self-derived cross-component candidates determined; or in response to said one or more inherited candidates being determined as the target cross-component candidate, determine one or more models based on said one or more inherited candidates determined; and encode or decode the second-colour block by using target prediction generated according to the target cross-component candidate.

Description

METHODS AND APPARATUS FOR VIDEO CODING IMPROVEMENT BY MODEL DERIVATION CROSS REFERENCE TO RELATED APPLICATIONS The present invention is a non-Provisional Application of and claims priority to U.S. Provisional Patent Application No. 63/511,921, filed on July 5, 2023. The U.S. Provisional Patent Application is hereby incorporated by reference in its entirety. FIELD OF THE INVENTION The present invention relates to video coding system. In particular, the present invention relates to coding for a chroma component using derived or inherited models. BACKGROUND AND RELATED ART Versatile video coding (VVC) is the latest international video coding standard developed by the Joint Video Experts Team (JVET) of the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG) . The standard has been published as an ISO standard: ISO/IEC 23090-3: 2021, Information technology -Coded representation of immersive media -Part 3: Versatile video coding, published Feb. 2021. VVC is developed based on its predecessor HEVC (High Efficiency Video Coding) by adding more coding tools to improve coding efficiency and also to handle various types of video sources including 3-dimensional (3D) video signals. Fig. 1A illustrates an exemplary adaptive Inter/Intra video encoding system incorporating loop processing. For Intra Prediction 110, the prediction data is derived based on previously coded video data in the current picture. For Inter Prediction 112, Motion Estimation (ME) is performed at the encoder side and Motion Compensation (MC) is performed based on the result of ME to provide prediction data derived from other picture (s) and motion data. Switch 114 selects Intra Prediction 110 or Inter Prediction 112 and the selected prediction data is supplied to Adder 116 to form prediction errors, also called residues. The prediction error is then processed by Transform (T) 118 followed by Quantization (Q) 120. The transformed and quantized residues are then coded by Entropy Encoder 122 to be included in a video bitstream corresponding to the compressed video data. The bitstream associated with the transform coefficients is then packed with side information such as motion and coding modes associated with Intra prediction and Inter prediction, and other information such as parameters associated with loop filters applied to underlying image area. The side information associated with Intra Prediction 110, Inter prediction 112 and in-loop filter 130, is provided to Entropy Encoder 122 as shown in Fig. 1A. When an Inter-prediction mode is used, a reference picture or pictures have to be reconstructed at the encoder end as well. Consequently, the transformed and quantized residues are processed by Inverse Quantization (IQ) 124 and Inverse Transformation (IT) 126 to recover the residues. The  residues are then added back to prediction data 136 at Reconstruction (REC) 128 to reconstruct video data. The reconstructed video data may be stored in Reference Picture Buffer 134 and used for prediction of other frames. As shown in Fig. 1A, incoming video data undergoes a series of processing in the encoding system. The reconstructed video data from REC 128 may be subject to various impairments due to a series of processing. Accordingly, in-loop filter 130 is often applied to the reconstructed video data before the reconstructed video data are stored in the Reference Picture Buffer 134 in order to improve video quality. For example, deblocking filter (DF) , Sample Adaptive Offset (SAO) and Adaptive Loop Filter (ALF) may be used. The loop filter information may need to be incorporated in the bitstream so that a decoder can properly recover the required information. Therefore, loop filter information is also provided to Entropy Encoder 122 for incorporation into the bitstream. In Fig. 1A, Loop filter 130 is applied to the reconstructed video before the reconstructed samples are stored in the reference picture buffer 134. The system in Fig. 1A is intended to illustrate an exemplary structure of a typical video encoder. It may correspond to the High Efficiency Video Coding (HEVC) system, VP8, VP9, H. 264 or VVC. The decoder, as shown in Fig. 1B, can use similar or portion of the same functional blocks as the encoder except for Transform 118 and Quantization 120 since the decoder only needs Inverse Quantization 124 and Inverse Transform 126. Instead of Entropy Encoder 122, the decoder uses an Entropy Decoder 140 to decode the video bitstream into quantized transform coefficients and needed coding information (e.g. ILPF information, Intra prediction information and Inter prediction information) . The Intra prediction 150 at the decoder side does not need to perform the mode search. Instead, the decoder only needs to generate Intra prediction according to Intra prediction information received from the Entropy Decoder 140. Furthermore, for Inter prediction, the decoder only needs to perform motion compensation (MC 152) acco