Method, apparatus and system for predicting a block of video samples

1. A method of decoding a current block encoded using intra-prediction, the method comprising:

determining prediction modes for coding blocks neighbouring the current block;

generating prediction values for edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying an intra-prediction process to the intra-prediction encoded current block if a number of the neighbouring coding blocks determined to use a prediction mode that is one of an intra-block copy prediction mode and a palette mode is greater than or equal to a predetermined threshold;

alternatively generating the prediction values for the edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying a filter to reference samples of the neighbouring blocks; and

decoding the current block based on the prediction values.

2. The method according to claim 1 , where the pre-determined threshold is equal to one (1).

3. The method according to claim 1 , where the pre-determined threshold is determined as an amount of blocks corresponding to a pre-defined proportion of neighbouring blocks determined to use the intra-block copy prediction mode or palette mode to the total amount of neighbouring blocks.

4. The method according to claim 1 , where the neighbouring blocks are the blocks corresponding to the reference samples.

5. The method according to claim 1 , where the neighbouring blocks are the blocks at least abutting left and above edges of a coding unit (CU) of the current block.

6. The method according to claim 5 , wherein the neighbouring blocks further include a block abutting a left-top corner of the coding unit (CU) of the current block.

7. The method according to claim 1 , where the neighbouring blocks are the blocks abutting at least left and above edges of a coding tree unit (CTU) of the current block.

8. The method according to claim 7 , wherein the neighbouring blocks further include a block abutting a left-top corner of the coding tree unit (CTU) of the current block.

9. The method according to claim 1 , where the neighbouring blocks are determined according to a pre-defined threshold distance.

10. A method according to claim 1 , wherein the filter is an intra-boundary filter.

11. A decoder decoding a current block encoded using intra-prediction, the decoder comprising:

a determining module configured to determine prediction modes for coding blocks neighbouring the current block;

a generator configured to generate prediction values for edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying an intra-prediction process to the intra-prediction encoded current block if a number of the neighbouring coding blocks determined to use a prediction mode that is one of an intra-block copy prediction mode and a palette mode is greater than or equal to a predetermined threshold;

alternatively generating the prediction values for the edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying a filter to reference samples of the neighbouring blocks; and

a decoder module configured to decode the current block based on the prediction values.

12. The decoder according to claim 11 , where the pre-determined threshold is equal to one (1).

13. The decoder according to claim 11 , where the pre-determined threshold is determined as an amount of blocks corresponding to a pre-defined proportion of neighbouring blocks determined to use the intra-block copy prediction mode or palette mode to the total amount of neighbouring blocks.

14. The decoder according to claim 11 , where the neighbouring blocks are the blocks corresponding to the reference samples.

15. The decoder according to claim 11 , where the neighbouring blocks are the blocks at least abutting left and above edges of the coding unit (CU) of the current block, and the neighbouring blocks further include a block abutting a left-top corner of the coding unit (CU) of the current block.

16. The decoder according to claim 11 , where the neighbouring blocks are the blocks abutting at least left and above edge of the coding tree unit (CTU) of the current block; and the neighbouring blocks further include a block abutting a left-top corner of the coding tree unit (CTU) of the current block.

17. The decoder according to claim 11 , where the neighbouring blocks are determined according to a pre-defined threshold distance.

18. A method of encoding a current block using intra-prediction, the method comprising:

determining a prediction mode for coding blocks neighbouring the current block;

generating prediction values for edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying an intra-prediction process to the intra-prediction encoded current block if a number of the neighbouring coding blocks determined to use a prediction mode that is an intra-block copy prediction mode or a palette mode is greater than or equal to a predetermined threshold;

otherwise generating the prediction values for the edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying a filter to reference samples of the neighbouring blocks; and

using the generated prediction values and the determined intra-prediction mode to encode the current block.

19. A non-transitory computer readable storage medium having a program recorded thereon, the program being executable by a processor to decode a current block encoded using intra-prediction, the program comprising:

code for determining prediction modes for coding blocks neighbouring the current block;

code for generating prediction values for edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying an intra-prediction process to the intra-prediction encoded current block if a number of the neighbouring coding blocks determined to use a prediction mode that is one of an intra-block copy prediction mode and a palette mode is greater than or equal to a predetermined threshold;

code for alternatively generating the prediction values for the edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying a filter to reference samples of the neighbouring blocks; and

code for decoding the current block based on the prediction values.

20. A video decoder for decoding a current block encoded using intra-prediction, the decoder comprising a processor coupled to a memory, the memory having a program recorded thereon and executable by the processor, the program comprising:

code for determining prediction modes for coding blocks neighbouring the current block;

code for generating prediction values for edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying an intra-prediction process to the intra-prediction encoded current block if a number of the neighbouring coding blocks determined to use a prediction mode that is one of an intra-block copy prediction mode and a palette mode is greater than or equal to a predetermined threshold;

code for alternatively generating the prediction values for the edge samples of the current block from intra-prediction reference samples of the neighbouring coding blocks by applying a filter to reference samples of the neighbouring blocks; and

code for decoding the current block based on the prediction values.