Methods and apparatus for signaling intra prediction for large blocks for video encoders and decoders

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.