computer program code configured to, with the at least one processor, cause the apparatus at least to: receive a coded picture comprising one or more slices; decode, from a slice header of a slice of the one or more slices, one or more tile identifiers indicative of one or more tile positions for one or more tiles in the slice; and decode slice data of the slice into a decoded picture starting from one or more tile positions for one or more tiles in the slice. 38. An apparatus according to Claim 37 wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to: decode, from the slice header, a block index relative to a tile of the one or more tiles, wherein the block index comprises a syntax element indicative of a block position for a block within the tile. 39. An apparatus according to any of Claims 37 to 38 wherein one tile identifier of the one or more tile identifiers is indicative of a tile that comprises a pre-defined block of the slice. 40. An apparatus according to any of Claims 37 to 39 wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to: decode one or more motion vectors associated with one or more prediction units in one or more coding units in the one or more tiles, wherein the one or more motion vectors apply in one or more anchor locations derived from one or more anchor location identifiers defining a position relative to the one or more tiles indicated by the one or more tile identifiers. 4 1. An apparatus according to any of Claims 37 to 40 wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to: decode one or more assignments of one or more tile identifier values for the one or more tile identifiers tile positions from a parameter set file.