Video coding apparatus and video decoding apparatus

A video encoding apparatus for encoding video data, the video encoding apparatus comprising:

• a header encoding circuit that encodes an enabled flag, indicating whether a synchronization process for a Context-Adaptive Binary Arithmetic Coding (CABAC) is performed, in a parameter set, wherein
• the header encoding circuit derives a raster scan Coding Tree Unit (CTU) address list equal to a sum of (a) a first CTU address in a tile group and (b) a product of a second CTU address of the tile group and a variable for a picture size,
• the first CTU address and the second CTU address specify a location in CTU units,
• the header encoding circuit derives a variable specifying a number of entry points based on a value of the enabled flag and the raster scan CTU address list,
• the header encoding circuit encodes a first syntax element and a second syntax element, in a case that a value of the variable is greater than 0,
• the first syntax element plus one specifies an entry point offset, and
• the second syntax element plus one specifies the number of bits of the first syntax element.

A video decoding method for decoding a picture, the video decoding method including:

• decoding an enabled flag, indicating whether a synchronization process for a Context-Adaptive Binary Arithmetic Coding (CABAC) is performed, in a parameter set;
• deriving a raster scan Coding Tree Unit (CTU) address list equal to a sum of (a) a first CTU address in a tile group and (b) a product of a second CTU address of the tile group and a variable for a picture size, wherein the first CTU address and the second CTU address specifies a location in CTU units;
• deriving a variable specifying a number of entry points based on a value of the enabled flag;
• and
• decoding a first syntax element and a second syntax element, in a case that a value of the variable is greater than 0, wherein
• the first syntax element plus one specifies an entry point offset, and
• the second syntax element plus one specifies the number of bits of the first syntax element.