Methods and apparatus for signaling intra prediction for large blocks for video encoders and decoders
Methods and apparatus are provided for signaling intra prediction for large blocks for video encoders and decoders. The intra prediction is signaled by selecting a basic coding unit size and assigning a single spatial intra partition type for the basic coding unit size. The single spatial intra partition type is selectable from among a plurality of spatial intra partition types. The at least one large block has a large block size greater than a block size of the basic coding unit. The intra prediction is hierarchical layer intra prediction and is performed for the at least one large block by at least one of splitting from the large block size to the basic coding unit size and merging from the basic coding unit size to the large block size.
1. A video decoder, comprising at least a memory and one or more processors, wherein the one or more processors are configured to:
decode picture data for at least a large block in a picture by determining that intra prediction is to be performed for the at least a large block, wherein the at least a large block has a large block size greater than a basic coding unit size, the large block size being one of 32×32 and 64×64 and the basic coding unit size being 16×16, wherein the intra prediction is signaled for the at least a large block and the one or more processors are configured to:
decode a binary split signaling syntax element specifying whether the large block is further split into four equally sized sub-blocks;
decode an intra prediction mode for said large block in the case where said binary split signaling syntax element specifies the large block is not further split;
otherwise in the case where said binary split signaling syntax element specifies the large block is further split:
decode for each sub-block, in the case where said sub-block is 32×32, a binary split signaling syntax element specifying whether said 32×32 sub-block is further split into four equally basic coding unit sized blocks and decode an intra prediction mode for said 32×32 subblock in the case where said binary split signaling syntax element specifies said 32×32 sub-block is not further split; and
decode for each sub-block, in the case where said sub-block is 16×16, a single spatial intra partition type, the single spatial intra partition type being determinable from among a plurality of spatial intra partition types, wherein the single spatial intra partition type selected from the plurality of spatial intra partition types is accompanied by at least (1) a single intra prediction type for the basic coding unit size which does not use a most probable intra prediction mode and (2) a single intra prediction type indicating the most probable intra prediction mode for the basic coding unit size.
2. The video decoder of claim 1 , wherein at least one of a spatial intra partition type table and an intra prediction mode table is pre-stored and used to decode the at least one large block.
3. The video decoder of claim 1 , wherein at least one of a spatial intra partition type table and an intra prediction mode table is received using one or more high level syntax elements and is used to decode the at least one large block.
4. A video encoder, comprising at least a memory and one or more processors, wherein the one or more processors are configured to:
encode picture data for at least a large block in a picture by determining that intra prediction is to be performed for the at least a large block, wherein the at least a large block has a large block size greater than a basic coding unit size, the large block size being one of 32×32 and 64×64 and the basic coding unit size being 16×16, wherein the intra prediction is signaled for the at least a large block and the one or more processors are configured to:
encode a binary split signaling syntax element specifying whether the large block is further split into four equally sized sub-blocks;
encode an intra prediction mode for said large block in the case where said binary split signaling syntax element specifies the large block is not further split;
otherwise in the case where said binary split signaling syntax element specifies the large block is further split:
encode for each sub-block, in the case where said sub-block is 32×32, a binary split signaling syntax element specifying whether said 32×32 sub-block is further split into four equally basic coding unit sized blocks and encode an intra prediction mode for said 32×32 subblock in the case where said binary split signaling syntax element specifies said 32×32 sub-block is not further split; and
encode for each sub-block, in the case where said sub-block is 16×16, a single spatial intra partition type, the single spatial intra partition type being determinable from among a plurality of spatial intra partition types, wherein the single spatial intra partition type selected from the plurality of spatial intra partition types is accompanied by at least (1) a single intra prediction type for the basic coding unit size which does not use a most probable intra prediction mode and (2) a single intra prediction type indicating the most probable intra prediction mode for the basic coding unit size.
5. The video encoder of claim 4 , wherein at least one of a spatial intra partition type table and an intra prediction mode table is pre-stored and used to encode the at least one large block.
6. The video encoder of claim 4 , wherein at least one of a spatial intra partition type table and an intra prediction mode table is encoded using one or more high level syntax elements and is used to encode the at least one large block.