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EP-4740478-A1 - METHODS AND APPARATUS FOR VIDEO CODING IMPROVEMENT BY STORING INFORMATION AND IMPLICIT DERIVATION

EP4740478A1EP 4740478 A1EP4740478 A1EP 4740478A1EP-4740478-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, input data associated with a current block comprising a first-colour block and a second-colour block is receiving, 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. A target CCP (Cross-Component Prediction) model for the current block is determined. The target CCP model is stored. The second-colour block is encoded or decoded by using target prediction generated according to the target CCP model for the current block.

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 (13)

  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 CCP (Cross-Component Prediction) model for the current block; storing the target CCP model; and encoding or decoding the second-colour block by using target prediction generated according to the target CCP model for the current block.
  2. The method of Claim 1, wherein the target CCP model comprises cross-component mode information, CCM (Cross-Component Model) information, or both.
  3. The method of Claim 1, wherein the target CCP model corresponds to a self-derived cross-component model or inherited cross-component model.
  4. The method of Claim 1, wherein the target CCP model comprising CCM (Cross-Component Model) information of inherited cross-component models and model parameters.
  5. The method of Claim 4, wherein the CCM information of the inherited cross-component models comprise CCLM (Cross-Component Linear Model) , CCCM (Convolutional Cross-Component Model) , CCCM with different filters, or a combination thereof.
  6. The method of Claim 4, further comprising refining the CCM information based on CCM information stored previously.
  7. The method of Claim 1, wherein inherited model parameters associated with CCM (Cross-Component Model) information are refined.
  8. The method of Claim 7, wherein the inherited model parameters are refined with different types of templates and/or different number of lines.
  9. The method of Claim 1, wherein the target CCP model corresponds to an inherited cross-component model from chroma intra fusion mode.
  10. The method of Claim 9, wherein the chroma intra fusion mode is derived by fusing a non-cross-component coded intra prediction and a cross-component coded intra prediction.
  11. The method of Claim 9, wherein when inheriting CCM information from a block or position coded by the chroma intra fusion mode, model parameters for obtaining cross-component coded intra prediction are inherited and further refined.
  12. The method of Claim 1, wherein the stored target CCP model is used or referenced by one or more following coding blocks.
  13. 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 CCP (Cross-Component Prediction) model for the current block; store the target CCP model; and encode or decode the second-colour block by using target prediction generated according to the target CCP model for the current block.

Description

METHODS AND APPARATUS FOR VIDEO CODING IMPROVEMENT BY STORING INFORMATION AND IMPLICIT 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 with cross-component information stored. 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