CN-122029805-A - Method and apparatus for filtered intra block copying

Abstract

The present invention provides a method for video decoding comprising obtaining a candidate list comprising block candidates, wherein the block candidates are reconstructed blocks in the same frame as a current block to be predicted, receiving an index indicating one of the block candidates as a selected block candidate, and predicting a sample value of the current block using a Filtered Intra Block Copy (FIBC) mode in response to determining that the selected block candidate has been predicted using the FIBC mode.

Inventors

• ZHU HONGZHENG
• GUO ZHEWEI
• XIU XIAOYU
• YAN NING
• CHEN WEI
• MA CHANGYUE
• WANG XIANGLIN
• YU BING

Assignees

• 北京达佳互联信息技术有限公司

Dates

Publication Date

20260512

Application Date

20240718

Priority Date

20230718

Claims (20)

1. 1. A method for video decoding, comprising: obtaining a candidate list comprising block candidates, wherein the block candidates are reconstructed blocks in the same frame as a current block to be predicted; receiving an index indicating one of the block candidates as a selected block candidate, and In response to determining that the selected block candidate has been predicted using a Filtered Intra Block Copy (FIBC) mode, a sample value of the current block is predicted using FIBC mode.
2. 2. The method of claim 1, wherein predicting the sample value of the current block using FIBC mode comprises: obtaining a set of filter coefficients corresponding to the filter shape, and A predicted sample value for the current block is derived based on the set of filter coefficients and a plurality of corresponding sample values associated with a reference block for the current block.
3. 3. The method of claim 2, wherein the set of filter coefficients is calculated based on sample values from both a training region associated with the reference block and a training region associated with the current block.
4. 4. The method of claim 2, wherein the set of filter coefficients is determined to be the same as filter coefficients for the selected block candidate.
5. 5. The method of claim 2, wherein the set of filter coefficients is obtained by performing a rounding operation or a truncation operation on filter coefficients for the selected block candidate.
6. 6. The method of claim 1, wherein the selected block candidate is stored for a plurality of Coding Units (CUs).
7. 7. A method for video encoding, comprising: Determining a candidate list comprising block candidates, wherein the block candidates are reconstructed blocks in the same frame as a current block to be predicted; Determining an index indicating one of the block candidates as a selected block candidate; Predicting sample values of the current block using a Filtered Intra Block Copy (FIBC) mode in response to determining that the selected block candidate has been predicted using the FIBC mode, and A bitstream is generated based on the candidate list, the index, and the predicted sample value of the current block.
8. 8. The method of claim 7, wherein predicting the sample value of the current block using FIBC mode comprises: Determining a set of filter coefficients corresponding to the filter shape, and A predicted sample value for the current block is derived based on the set of filter coefficients and a plurality of corresponding sample values associated with a reference block for the current block.
9. 9. The method of claim 8, wherein the set of filter coefficients is calculated based on sample values from both a training region associated with the reference block and a training region associated with the current block.
10. 10. The method of claim 8, wherein the set of filter coefficients is determined to be the same as filter coefficients for the selected block candidate.
11. 11. The method of claim 8, wherein the set of filter coefficients is obtained by performing a rounding operation or a truncation operation on filter coefficients for the selected block candidate.
12. 12. The method of claim 7, wherein the selected block candidate is stored for a plurality of Coding Units (CUs).
13. 13. A method for video decoding, comprising: Determining an initial prediction block of a current block to be predicted based on a first block vector, wherein the first block vector is a fractional block vector between the current block and a reference block of the current block; Responsive to determining that a reference template based on a current template associated with the current block and a first block vector corresponds to an invalid template region, determining the reference template based on the current template and a second block vector, wherein the second block vector is an integer block vector modified from the first block vector based on a truncating operation or a rounding operation; obtaining a set of filter coefficients corresponding to a filter shape based at least on sample values from both the current template and the reference template, and A final prediction block of the current block is derived that includes predicted sample values of the current block based on the set of filter coefficients and a plurality of corresponding sample values associated with the reference block.
14. 14. A method for video encoding, comprising: Determining an initial prediction block of a current block to be predicted based on a first block vector, wherein the first block vector is a fractional block vector between the current block and a reference block of the current block; Responsive to determining that a reference template based on a current template associated with the current block and a first block vector corresponds to an invalid template region, determining the reference template based on the current template and a second block vector, wherein the second block vector is an integer block vector modified from the first block vector based on a truncating operation or a rounding operation; obtaining a set of filter coefficients corresponding to a filter shape based at least on sample values from both the current template and the reference template; Deriving a final prediction block of the current block including predicted sample values of the current block based on the set of filter coefficients and a plurality of corresponding sample values associated with the reference block, and Generating a bitstream based on the final prediction block.
15. 15. An apparatus, comprising: One or more processors, and One or more storage devices storing computer-executable instructions that, when executed, cause the one or more processors to perform the operations of the method of any of claims 1 to 14.
16. 16. A computer program product storing computer-executable instructions that, when executed, cause one or more processors to perform the operations of the method of any one of claims 1 to 14.
17. 17. A computer-readable storage medium storing instructions that, when executed by a computing device having one or more processors, cause the one or more processors to: Performing the method according to any of claims 1-6, 13 and storing a bitstream to be decoded by the method according to any of claims 1-6, 13, or The method according to any of claims 7-12, 14 is performed and the bit stream generated by the method according to any of claims 7-12, 14 is stored.
18. 18. A computer readable medium storing a bitstream, wherein, The bitstream is to be decoded by performing the operations of the method according to any of claims 1-6, 13, or The bit stream is obtained by performing the operations of the method according to any of claims 7-12, 14.
19. 19. A method for receiving a bitstream to be decoded by the method according to any of claims 1-6, 13.
20. 20. A method for transmitting a bitstream, the bitstream being generated by the method according to any one of claims 7-12, 14.

Description

Method and apparatus for filtered intra block copying Cross Reference to Related Applications The present application is based on and claims priority from provisional application No. 63/514,237 filed on 7.18 of 2023, the entire contents of which are incorporated herein by reference in their entirety. Technical Field The application relates to video codec and compression. More particularly, the present application relates to methods and apparatus for improving the codec efficiency of Filtered Intra Block Copy (FIBC). Background Various electronic devices (e.g., digital televisions, laptop or desktop computers, tablet computers, digital cameras, digital recording devices, digital media players, video game consoles, smart phones, video teleconferencing devices, video streaming devices, etc.) support digital video. The electronic device sends and receives or otherwise communicates digital video data over a communication network and/or stores the digital video data on a storage device. Because of the limited bandwidth capacity of the communication network and the limited storage resources of the storage device, video data may be compressed using video codec according to one or more video codec standards before it is transmitted or stored. For example, video coding standards include general video coding (VVC), joint exploration test model (JEM), high efficiency video coding (HEVC/h.265), advanced video coding (AVC/h.264), moving Picture Experts Group (MPEG) coding, and so forth. Video coding typically employs prediction methods (e.g., inter-prediction, intra-prediction, etc.) that exploit redundancy inherent in video data. Video codec aims at compressing video data into a form using a lower bit rate while avoiding or minimizing degradation of video quality. Disclosure of Invention Embodiments of the present disclosure provide methods and apparatus for improving the codec efficiency of image/video blocks applying FIBC technology. According to one aspect of the present disclosure, there is provided a method for video decoding, comprising obtaining a candidate list comprising block candidates, wherein the block candidates are reconstructed blocks in the same frame as a current block to be predicted, receiving an index indicating one of the block candidates as a selected block candidate, and predicting a sample value of the current block using a Filtered Intra Block Copy (FIBC) mode in response to determining that the selected block candidate has been predicted using the FIBC mode. According to one aspect of the present disclosure, there is provided a method for video encoding, comprising determining a candidate list comprising block candidates, wherein the block candidates are reconstructed blocks in the same frame as a current block to be predicted, determining an index indicating one of the block candidates as a selected block candidate, predicting sample values of the current block using a Filtered Intra Block Copy (FIBC) mode in response to determining that the selected block candidate has been predicted using the FIBC mode, and generating a bitstream based on the candidate list, the index, and the predicted sample values of the current block. According to one aspect of the disclosure, there is provided a method for video decoding, comprising determining an initial prediction block of a current block to be predicted based on a first block vector, wherein the first block vector is a fractional block vector between the current block and a reference block of the current block, determining, based on a current template associated with the current block and a first block vector, a reference template based on the current template and a second block vector in response to determining that the reference template corresponds to an invalid template region, wherein the second block vector is an integer block vector modified from the first block vector based on a truncation operation or a rounding operation, obtaining a set of filter coefficients corresponding to a filter shape based on at least sample values from both the current template and the reference template, and deriving a final prediction block of the current block comprising predicted sample values of the current block based on the set of filter coefficients and a plurality of corresponding sample values associated with the reference block. According to one aspect of the disclosure, there is provided a method for video coding, comprising determining an initial prediction block of a current block to be predicted based on a first block vector, wherein the first block vector is a fractional block vector between the current block and a reference block of the current block, determining a reference template based on a current template associated with the current block and a first block vector based on the current template and a second block vector in response to determining that the reference template corresponds to an invalid template region, wherein the second block ve