JVET-L0374 On Tile Information Signalling for VVC [S. Deshpande, Y. Yasugi (Sharp)]

Syntax, semantics and decoding process is proposed for VVC for tile information signalling. The proposed approach includes signalling of tiles and tile sets.

This has substantial similarities with the Huawei-Nokia proposal.

High level description of the proposed approach is as follows:

• Information regarding tile structure for a picture is signaled in parameter set: For this currently all HEVC syntax elements in PPS are proposed to be included.
• Optional information regarding tile sets is signaled in parameter sets: This information helps creation of slices, allows knowing the tile set structure in advance, and in turn enables parallel decoding of tile sets (described further in the next point).
• Coding tree block and tile scanning conversion process: Process from HEVC is adopted and modified to support tile sets. The raster ordering of coded tree blocks (CTBs/ CTUs) is row-by-row in tile raster scan within a tile set and the tile sets themselves are raster ordered within the picture. The proposed approach makes the coded data within a tile set contiguous which can help extraction of the tile set portion of the bitstream and parallel decoding and/or sub-bitstream extraction of those bitstream portions.
• A slice (or a segment or a tile group) consists of header and data for a single complete tile set. Slice (or a segment or a tile group) header signalling consists of signalling of a tile set identifier and entry point signalling for tiles within the tile set.

The tile sets are proposed to have a grid structure, like the assignment of CTUs to tiles. The possibility of greater flexibility than such a grid structure, either for the assignment of CTUs to tiles or for assignment of tiles to tile groups, was discussed.

A participant commented that stitching of data together to form a single bitstream is sometimes needed rather than the handling of different bitstreams separately.

An example layout is multipoint conferencing with a large rectangle for the presenter and

With the tile sets established at the parameter set level, the ID sent at the slice level is proposed to indicate which tile set is in the slice.