Encoder and decoder
An encoder includes circuitry and memory coupled to the circuitry. The circuitry: assigns a picture level slice index and a subpicture level slice index to each of the slices, the picture level slice index being assigned at a picture level, the subpicture level slice index being assigned at a subpicture level; for each of the slices, encodes the subpicture level slice index of the slice into a slice header of the slice; and encodes each of the slices into a bitstream. The picture level slice index assigned to a current slice to be processed that is included in a current subpicture to be processed is calculated by adding (i) the subpicture level slice index of the current slice and (ii) a total number of slices included in one or more subpictures that have been encoded prior to the current subpicture out of the subpictures.
1 . An encoder which encodes a picture into a bitstream, the picture including subpictures, the picture including slices, each of the slices being included in one of the subpictures, the encoder comprising:
memory; and
circuitry coupled to the memory and configured to:
encode a subpicture level slice index of a current slice into a slice header, the subpicture level slice index indicating an index number of the current slice in a current subpicture, the current slice being included in the current subpicture; and
encode the current slice into the bitstream, wherein
a picture level slice index of the current slice is calculated by adding (i) the subpicture level slice index of the current slice and (ii) a total number of slices included in one or more subpictures that have been encoded prior to the current subpicture, the picture level slice index indicating an index number of the current slice in a current picture.
2 . A decoder which decodes a picture from a bitstream, the picture including subpictures, the picture including slices, each of the slices being included in one of the subpictures, the decoder comprising:
memory; and
circuitry coupled to the memory and configured to:
decode a subpicture level slice index of a current slice from a slice header, the subpicture level slice index indicating an index number of the current slice in a current subpicture, the current slice being included in the current subpicture; and
decode the current slice from the bitstream, wherein
a picture level slice index of the current slice is calculated by adding (i) the subpicture level slice index of the current slice and (ii) a total number of slices included in one or more subpictures that have been encoded prior to the current subpicture, the picture level slice index indicating an index number of the current slice in a current picture.
3 . A non-transitory computer readable medium storing a bitstream and computer-executable instructions,
wherein the bitstream includes (i) a current slice, (ii) a subpicture level slice index of the current slice in a slice header, and (iii) a parameter according to which the computer-executable instructions cause a decoder to perform:
decoding the subpicture level slice index; and
decoding the current slice, wherein
the subpicture level slice index indicates an index number of the current slice in a current subpicture,
the current slice is included in the current subpicture, and
a picture level slice index of the current slice is calculated by adding (i) the subpicture level slice index of the current slice and (ii) a total number of slices included in one or more subpictures that have been encoded prior to the current subpicture, the picture level slice index indicating an index number of the current slice in a current picture.