Coding mode information propagation for video coding
Coding mode information of a current block is propagated to neighbor blocks even when the coding mode is not selected for a current block. Such propagation may be limited, for example to one block only or to multiple generation of copies. Different propagation modes are proposed: left to right direction, top to bottom direction, bottom-right diagonal direction, first available information, or last coded information. The coding mode propagation allows to improve further predictions since a further block will benefit from the information from its neighbors.
1. A method comprising, for a current block of a picture:
selecting a neighbor block; and
copying coding mode information of the neighbor block to the current block, wherein a coding mode of the neighbor block is different from a coding mode of the current block and wherein the coding mode information is not used for the current block.
2. The method of claim 1 , wherein the coding mode information from the neighbor block is not copied to the current block when the coding mode of the neighbor block is the same as the coding mode of the current block.
3. The method of claim 1 , wherein the copied mode information from the neighbor block is used to perform prediction for a further block of the picture but not for the current block.
4. The method of claim 1 , wherein the coding mode information comprises intra-direction information or motion information or motion vector or an affine model.
5. The method of claim 1 , wherein the neighbor block is the block at the left of the current block or the block at the top of the current block or the block at the bottom of the current block or the block at the top-left of the current block.
6. The method of claim 1 , wherein the neighbor block is the last block that was coded prior to the current block following a coding scan order.
7. The method of claim 1 , wherein the neighbor block is the first available block among a set of blocks.
8. The method of claim 7 , wherein the set of blocks is an ordered list comprising at least the block at the top of the current block, the block at the left of the current block, the block at the top right of the current block, the block at the top left of the current block.
9. The method of claim 1 , wherein a counter is associated with the coding mode information to count the number of generations of the coding mode information, and wherein the copy of coding mode information is only allowed up to a maximum number of generations.
10. The method of claim 9 , wherein the maximum number of generations is 1.
11. An apparatus comprising a processor configured to, for a current block of a picture:
select a neighbor block; and
copy coding mode information of the neighbor block to the current block, wherein a coding mode of the neighbor block is different from a coding mode of the current block and wherein the coding mode information is not used for the current block.
12. The apparatus of claim 11 , wherein the coding mode information from the neighbor block is not copied to the current block when the coding mode of the neighbor block is the same as the coding mode of the current block.
13. The apparatus of claim 11 , wherein the copied mode information from the neighbor block is used to perform prediction for a further block of the picture but not for the current block.
14. The apparatus of claim 11 , wherein the coding mode information comprises intra-direction information or motion information or motion vector or an affine model.
15. The apparatus of claim 11 , wherein the neighbor block is the block at the left of the current block or the block at the top of the current block or the block at the bottom of the current block or the block at the top-left of the current block.
16. The apparatus of claim 11 , wherein the neighbor block is the last block that was coded prior to the current block following a coding scan order.
17. The apparatus of claim 11 , further comprising a counter associated with the coding mode information to count the number of generation of the coding mode information, wherein the copy of coding mode information is only allowed up to a maximum number of generations.
18. The apparatus of claim 17 , wherein the maximum number of generations is 1.
19. A non-transitory computer readable medium comprising program code instructions for implementing the method according to claim 1 when executed by a processor.