A method for handling chroma subsampling formats in machine learning-based picture coding.

Abstract

We provide video coding, encoders, and decoders that further improve efficiency based on trained networks. [Solution] To handle lumer-chroma channels of different sizes, the chroma component is upsampled so that the resulting upsampled chroma component has a resolution matching one of the lumer components. The lumer and upsampled chroma components are then encoded into a bitstream. To reconstruct the picture portion, the lumer component and an intermediate chroma component matching the resolution of the lumer component are decoded from the bitstream, and then the intermediate chroma component is downsampled. The subsampled chroma format is handled by an autoencoder / autodecoder framework while preserving the lumer channel.

Claims

1. A method for encoding a picture portion, wherein the picture portion includes a rumor component and a chroma component having a resolution lower than the resolution of the rumor component, and the method is The steps include: upsampling the chroma component to obtain an upsampled chroma component that matches the resolution of the chroma component; The steps include encoding the chroma component and the upsampled chroma component into a bitstream. Includes, The upsampling step includes processing the chroma component by a trained network, The step of processing the chroma component by a trained network includes inputting the lumen component and the chroma component into the trained network, and outputting the upsampled chroma component from the trained network. The method wherein the encoding step is performed by a variational autoencoder (VAE).

2. The method according to claim 1, wherein the upsampling of the chroma component is based on a sample of the luma component.

3. The trained network comprises at least two processing layers, The first of the at least two processing layers performs upsampling based on the input chroma component. The method according to claim 1, wherein the second of the at least two processing layers processes the output of the first layer together with the luma component.

4. The method according to claim 3, wherein processing the output of the first layer together with the lumar component includes adding the lumar component and the upsampled chroma component element by element.

5. The method according to claim 1, wherein the step of upsampling includes the step of inserting a line of sample after every n lines of the chroma component sample, where the lines are rows and / or columns and n is an integer of 1 or more.

6. The method according to claim 1 or 5, wherein the step of upsampling includes inserting a line of sample having a value of 0 after every n lines of the chroma component sample, wherein the lines are rows and / or columns and n is an integer of 1 or more.

7. The method according to claim 1 or 5, wherein the step of upsampling includes inserting a line of sample having a value equal to the nearest neighbor sample in the chroma component after every n lines of the sample in the chroma component, wherein the lines are rows and / or columns and n is an integer of 1 or more.

8. A method for decoding a picture portion from a bitstream, wherein the picture portion includes a rumor component and a chroma component having a resolution lower than the resolution of the rumor component, and the method is The steps include decoding the lumens component and an intermediate chroma component that matches the resolution of the lumens component from the bitstream, The steps include downsampling the intermediate chroma component to obtain the chroma component of the picture portion, and Includes, The downsampling step includes processing the intermediate chromatic components by a trained network, The step of processing the intermediate chroma component by a trained network includes inputting the intermediate chroma component into the trained network and outputting the chroma component from the trained network. The decoding step is performed by a variational autoencoder (VAE).

9. The trained network comprises at least two processing layers, The first of the at least two processing layers performs processing on the input intermediate chroma component. The method according to claim 8, wherein the second of the at least two processing layers performs downsampling of the output of the first layer.

10. The downsampling of the intermediate chromatic component is based on a sample of the lumen component, according to claim 8 or 9.

11. The method according to any one of claims 8 to 10, wherein the step of processing the intermediate chroma component by a trained network includes the step of inputting the chroma component into the trained network.

12. The method according to any one of claims 9 to 11, wherein the first layer is processed together with the luma component to obtain the intermediate chromat component.

13. The method according to claim 8, wherein the downsampling step includes a step of removing lines of the sample after every n lines of the intermediate chromatic component of the sample, wherein the lines are rows and / or columns and n is an integer of 1 or more.

14. A computer program stored on a non-temporary medium, which includes code that, when executed on one or more processors, performs the method described in any one of claims 1 to 13.

15. An encoder for encoding a picture portion, wherein the picture portion includes a rumor component and a chroma component having a resolution lower than the resolution of the rumor component, and the encoder is One or more processors, A non-temporary computer-readable storage medium coupled to one or more processors and storing a program for execution by the one or more processors, wherein the program is configured to perform the method described in any one of claims 1 to 7 when the program is executed by the one or more processors, and An encoder equipped with the following features.

16. A decoder for decoding a picture portion from a bitstream, wherein the picture portion includes a rumor component and a chroma component having a resolution lower than the resolution of the rumor component, and the decoder One or more processors, A non-temporary computer-readable storage medium coupled to one or more processors and storing a program for execution by the one or more processors, wherein the decoder is configured to perform the method described in any one of claims 8 to 13 when the program is executed by the one or more processors. A decoder equipped with a decoder.

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