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EP-4740476-A1 - METHODS AND APPARATUS OF INHERITING CROSS-COMPONENT MODELS FROM NON-INTRA CODED BLOCKS FOR CROSS-COMPONENT PREDICTION MERGE MODE

EP4740476A1EP 4740476 A1EP4740476 A1EP 4740476A1EP-4740476-A1

Abstract

A method and apparatus for coding colour pictures 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 received, 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. A cross-component model for the current block is determined. A target cross-component predictor is derived by applying the cross-component model to reconstructed first-colour samples. The second-colour block is encoded or decoded by using prediction data comprising the target cross-component predictor.

Inventors

  • TSENG, HSIN-YI
  • CHIANG, Man-Shu
  • TSAI, CHIA-MING
  • HSU, CHIH-WEI

Assignees

  • MediaTek Inc.

Dates

Publication Date
20260513
Application Date
20240605

Claims (14)

  1. A method of coding colour pictures 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 cross-component model for the current block; deriving a target cross-component predictor by applying the cross-component model to reconstructed first-colour samples; and encoding or decoding the second-colour block by using prediction data comprising the target cross-component predictor.
  2. The method of Claim 1, wherein the cross-component model for the current block is stored, referenced by following coding blocks, or both.
  3. The method of Claim 2, wherein all model parameters of the cross-component model are stored.
  4. The method of Claim 2, wherein a subset of model parameters of the cross-component model is stored.
  5. The method of Claim 2, wherein if a target following coding block is coded in an intra mode, the target following coding block is allowed to use the cross-component model stored.
  6. The method of Claim 2, wherein if a target following coding block is coded in the non-intra mode, the target following coding block is allowed to use the cross-component model stored.
  7. The method of Claim 1, wherein the cross-component model is derived from reconstructed first-colour samples and reconstructed second-colour samples.
  8. The method of Claim 7, wherein the reconstructed first-colour samples and the reconstructed second-colour samples are from regions indicated by a motion vector or a block vector.
  9. The method of Claim 1, wherein the cross-component model is derived based on CCRM (Cross-Component Residual Model) .
  10. The method of Claim 1, wherein the cross-component model is inherited from a neighbouring block.
  11. The method of Claim 10, wherein the neighbouring block corresponds to a spatial neighbouring block or a temporal neighbouring block.
  12. The method of Claim 1, wherein different cross-component models associated with blocks coded in different modes are stored in different buffers.
  13. The method of Claim 12, wherein a first cross-component model associated with intra-coded blocks and a second cross-component model associated with inter-coded blocks are stored in two different buffers.
  14. An apparatus for coding colour pictures 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 cross-component model for the current block; derive a target cross-component predictor by applying the cross-component model to reconstructed first-colour samples; and encode or decode the second-colour block by using prediction data comprising the target cross-component predictor.

Description

METHODS AND APPARATUS OF INHERITING CROSS-COMPONENT MODELS FROM NON-INTRA CODED BLOCKS FOR CROSS-COMPONENT PREDICTION MERGE MODE CROSS REFERENCE TO RELATED APPLICATIONS The present invention is a non-Provisional Application of and claims priority to U.S. Provisional Patent Application No. 63/511,920, 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. In particular, the present invention relates to inter prediction for chroma component by applying a cross-component model to reconstructed luma samples. 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