Video coding comprising rectangular tile group signaling

A method for decoding a picture from a bitstream, the method comprising:

• decoding a tile partition structure from one or more syntax elements in the bitstream;
• determining a number of tiles N in the picture;
• decoding a number of slices in the picture, wherein each slice comprises an integer number of tiles;
• deriving a size for a current slice, wherein deriving the size for the current slice comprises:
• deriving a width of the current slice from a first syntax element from the bitstream representing a width of the current slice in number of tiles;
• and
• deriving a height of the current slice from a second syntax element from the bitstream representing a height of the current slice in number of tiles;
• deriving a top-left position of the current slice as a location of a first tile in raster scan order that is not included in one or more previously derived slices;
• and
• using the derived size and location to decode the picture.

A decoder for decoding a picture from a bitstream, the decoder comprising processing circuitry, wherein the decoder is configured to perform a method comprising:

• decoding a tile partition structure from one or more syntax elements in the bitstream;
• determining a number of tiles N in the picture;
• decoding a number of slices in the picture, wherein each slice comprises an integer number of tiles;
• deriving a size for a current slice, wherein deriving the size for the current slice comprises:
• deriving a width of the current slice from a first syntax element from the bitstream representing a width of the current slice in number of tiles;
• and
• deriving a height of the current slice from a second syntax element from the bitstream representing a height of the current slice in number of tiles;
• deriving a top-left position of the current slice as a location of a first tile in raster scan order that is not included in one or more previously derived slices;
• and
• using the derived size and location to decode the picture.

An encoder for encoding a picture into a bitstream, the encoder comprising processing circuitry, wherein the encoder is configured to perform a method comprising:

• encoding a tile partition structure as one or more syntax elements in the bitstream;
• determining a number of tiles N in the picture;
• encoding a number of slices in the picture, wherein each slice comprises an integer number of tiles;
• including in the bitstream a first syntax element representing a width of the current slice in number of tiles;
• including in the bitstream a second syntax element representing a height of the current slice in number of tiles;
• deriving a top-left position of the current slice as a location of a first tile in raster scan order that is not included in one or more previously derived slices;
• and
• using the width, height, and location to encode the picture.