Selective Inter-Component Transformation (ICT) for Image and Video Coding

Abstract

To provide a more flexible method and apparatus for joint component coding of images or videos.SOLUTION: An encoder 601 for encoding a plurality of components of an image content region of an image to be encoded, includes obtaining a plurality of components representing the image content region, selecting an inter-component transform from a set of inter-component transforms, encoding the plurality of components using the selected inter-component transform to obtain encoded components, and providing the encoded components.SELECTED DRAWING: Figure 4a

Claims

1. A block-based video decoding method, wherein the method is From the data stream, decode a flag indicating that the residual samples corresponding to the first chroma block and the residual samples corresponding to the second chroma block are joint-coded as residual samples corresponding to the joint-coded block. Decoding one or more coded block flags from the data stream, indicating whether at least one residual sample corresponding to the first chroma block is non-zero and whether at least one residual sample corresponding to the second chroma block is non-zero. When the aforementioned flag indicates joint coding, implicit signaling based on the one or more coding block flags identifies one of several predefined inter-component conversion methods to be applied. Decoding the residual samples corresponding to the joint-coded blocks from the aforementioned data stream, A method comprising: obtaining a residual sample corresponding to the first chromatic block and a residual sample corresponding to the second chromatic block by applying a reverse intercomponent transformation to the residual sample corresponding to the joint coding block based on a coefficient corresponding to the identified intercomponent transformation method.

2. The method according to claim 1, wherein the first chroma block contains the blue chroma component of the picture block, and the second chroma block contains the red chroma component of the picture block.

3. The method according to claim 1, wherein decoding the flag includes applying a context model.

4. The method according to claim 1, wherein the residual sample corresponding to the first chroma block has the same value as the residual sample corresponding to the joint coding block, and the residual sample corresponding to the second chroma block has the value obtained by multiplying the residual sample of the joint coding block by a coefficient corresponding to the identified intercomponent conversion method.

5. A block-based video encoding method, wherein the method is For the residual sample corresponding to the first chromatic block and the residual sample corresponding to the second chromatic block, one of several predefined inter-component conversion methods is selected. Based on the coefficients corresponding to the selected inter-component transformation method, a forward inter-component transformation is applied to the residual sample corresponding to the first chroma block and the residual sample corresponding to the second chroma block to generate a residual sample corresponding to the joint-coding block. The data stream is encoded with a flag indicating that the residual samples corresponding to the first chroma block and the residual samples corresponding to the second chroma block are jointly coded as residual samples corresponding to the jointly coded block. Encoding one or more coded block flags into the data stream, indicating whether at least one residual sample corresponding to the first chroma block is non-zero and whether at least one residual sample corresponding to the second chroma block is non-zero; A method comprising encoding the residual samples corresponding to the joint coding blocks into the data stream.

6. The method according to claim 5, wherein the first chroma block contains the blue chroma component of the picture block, and the second chroma block contains the red chroma component of the picture block.

7. The method according to claim 5, wherein encoding the flag includes applying a context model.

8. The method according to claim 5, wherein the residual sample corresponding to the first chroma block has the same value as the residual sample corresponding to the joint coding block, and the residual sample corresponding to the second chroma block has a value obtained by multiplying the residual sample of the joint coding block by a coefficient corresponding to the selected intercomponent conversion method.

9. A block-based video decoder for joint-coded residual samples, comprising one or more processors configured to perform the method described in any one of claims 1 to 4.

10. A block-based video encoding apparatus for joint-coded residual samples, comprising one or more processors configured to perform the method described in any one of claims 5 to 8.

11. A non-temporary computer-readable digital storage medium on which a computer program having program code that, when executed, performs the method described in any one of claims 1 to 8 is recorded.

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