Methods, apparatus, and programs for video decoding.

Abstract

Coded information of a current block predicted in an intra-directional mode and neighboring blocks of the current block is received. It is determined that the intra-directional mode of the current block is associated with an angle that is one of less than 90 degrees and greater than 180 degrees. In response to the intra-directional mode of the current block being associated with an angle, it is determined whether a delta angle associated with the current block is a predefined delta angle. In response to the delta angle associated with the current block not being a predefined delta angle, unidirectional intra prediction is applied to the current block instead of bidirectional intra prediction. Samples of the current block are reconstructed based on neighboring reference samples on a reference line determined according to the unidirectional intra prediction.

Claims

1. A method for performing video decoding, which is performed by a video decoder. Receiving coded information of the current block and adjacent blocks of the current block predicted in intradirectional mode from a coded video bitstream, Determining that the intra-directional mode of the current block is associated with an angle that is one of the following: less than 90 degrees and greater than 180 degrees, In accordance with the fact that the intra-directional mode of the current block is associated with an angle that is one of less than 90 degrees and greater than 180 degrees, it is determined whether the delta angle associated with the current block is a predefined delta angle, In accordance with the fact that the delta angle associated with the current block is not the predefined delta angle, a unidirectional intra-prediction is applied to the current block instead of a bidirectional intra-prediction, (i) Reconstruct a sample of the current block based on adjacent reference samples on a reference line determined according to the unidirectional intra prediction applied when the intra-directional mode of the current block is associated with an angle that is less than 90 degrees and greater than 180 degrees, and (ii) when the delta angle associated with the current block is not the predefined delta angle. Methods that include...

2. (iii) determining that the bidirectional intra prediction is applied to the current block based on the delta angle, which is the predefined delta angle, and (iv) the reference line, which includes reference samples for intra prediction, wherein the reference line includes a reference sample row adjacent to and above the current block, and a reference sample column adjacent to the left of the current block. The method according to claim 1.

3. The method according to claim 1, wherein the predefined delta angle is one of 0 degrees, 2 degrees, and -2 degrees.

4. The method according to claim 1, wherein the predefined delta angle falls within one of a first range from -2 to 0 and a second range from 0 to 2.

5. The aforementioned reconstruction means Reconstructing the sample of the current block based on two adjacent reference samples selected from the reference line based on the direction angle indicated by the bidirectional intra prediction. The method according to claim 2, further comprising:

6. The method according to claim 5, wherein the direction angle indicated by the bidirectional intra-prediction is equal to the sum of the delta angle and the direction angle indicated by the intra-directional mode of the current block.

7. The method according to claim 2, wherein the angle associated with the intra-directional mode of the current block is within a subset of the angular range less than 90 degrees and greater than 180 degrees.

8. The method according to claim 1, wherein the predefined delta angle is one of -9 degrees, -6 degrees, -3 degrees, 0 degrees, 3 degrees, 6 degrees, and 9 degrees.

9. Each angle within the aforementioned angle range has its own index value, The method according to claim 7, wherein each angle within the subset of the angle range has one of an even index value and one of an odd index value.

10. The method according to claim 1, wherein the predefined delta angle is obtained based on a predefined mapping table showing a correlation between the candidate's predefined delta angle and the candidate's intra-directional mode of the current block.

11. Determining whether the bidirectional intra prediction is applied to the current block based on at least one prediction mode of the adjacent blocks, which is a non-directional mode. The method according to claim 1, further comprising:

12. The method according to claim 1, wherein the predefined delta angle is included in the coded information at one of the sequence level, frame level, or slice level.

13. A device for video decoding, Equipped with a processing circuit, The aforementioned processing circuit is From the coded video bitstream, coded information of the current block and adjacent blocks of the current block, predicted in intra-directional mode, is received. Determine that the intra-directional mode of the current block is associated with an angle that is one of the following: less than 90 degrees and greater than 180 degrees. Depending on whether the intra-directional mode of the current block is associated with an angle that is one of less than 90 degrees and greater than 180 degrees, it is determined whether the delta angle associated with the current block is a predefined delta angle. Depending on whether the delta angle associated with the current block is not the predefined delta angle, a unidirectional intra-prediction is applied to the current block instead of a bidirectional intra-prediction. (i) Reconstruct a sample of the current block based on adjacent reference samples on a reference line determined according to the unidirectional intra prediction, which is applied when the intra-directional mode of the current block is associated with an angle that is less than 90 degrees and greater than 180 degrees, and (ii) when the delta angle associated with the current block is not the predefined delta angle. Device.

14. The aforementioned processing circuit is The apparatus according to claim 13, further configured to determine that the bidirectional intra prediction is applied to the current block based on (iii) the delta angle which is the predefined delta angle, and (iv) the reference line which includes reference samples for intra prediction, wherein the reference line includes a reference sample row adjacent to and above the current block and a reference sample column adjacent to the left side of the current block.

15. The apparatus according to claim 13, wherein the predefined delta angle is one of 0 degrees, 2 degrees, and -2 degrees.

16. The apparatus according to claim 13, wherein the predefined delta angle falls within one of a first range from -2 to 0 and a second range from 0 to 2.

17. The aforementioned processing circuit is Based on the direction angle indicated by the bidirectional intra-prediction, the sample of the current block is reconstructed based on two adjacent reference samples selected from the reference line. The apparatus according to claim 14, further configured as follows.

18. The apparatus according to claim 17, wherein the direction angle indicated by the bidirectional intra-prediction is equal to the sum of the delta angle and the direction angle indicated by the intra-directional mode of the current block.

19. The apparatus according to claim 14, wherein the angle associated with the intra-directional mode of the current block is within a subset of the angular range less than 90 degrees and greater than 180 degrees.

20. When executed by at least one processor, the at least one processor, Receiving coded information of the current block and adjacent blocks of the current block predicted in intradirectional mode from a coded video bitstream, Determining that the intra-directional mode of the current block is associated with an angle that is one of the following: less than 90 degrees and greater than 180 degrees, In accordance with the fact that the intra-directional mode of the current block is associated with an angle that is one of less than 90 degrees and greater than 180 degrees, it is determined whether the delta angle associated with the current block is a predefined delta angle, In accordance with the fact that the delta angle associated with the current block is not the predefined delta angle, a unidirectional intra-prediction is applied to the current block instead of a bidirectional intra-prediction, (i) Reconstruct a sample of the current block based on adjacent reference samples on a reference line determined according to the unidirectional intra prediction applied when the intra-directional mode of the current block is associated with an angle that is less than 90 degrees and greater than 180 degrees, and (ii) when the delta angle associated with the current block is not the predefined delta angle. A program that contains instructions to execute.

Images