Image encoding apparatus, method of image encoding, and recording medium, image decoding apparatus, method of image decoding, and recording medium

Abstract

Encoded data is decoded based on tile data division information, tile data position information, block line data division information, and block line data position information. The tile data division information indicates whether the encoded data is composed of tile data items that serve as encoded data items of tiles. The tile data position information indicates positions of the tile data items. The block line data division information indicates whether each tile data item is composed of first block line data and second block line data. The first block line data serves as encoded data of a first block line that is a set of blocks arranged linearly. The second block line data serves as encoded data of a second block line next to the first block line. The block line data position information indicates a position of the second block line data.

1 . An image decoding apparatus that decodes encoded data obtained by dividing a frame of image data into rectangular tiles and encoding the image data on a tile-by-tile basis, the apparatus comprising:
 a deriving unit configured to derive tile data division information, tile data position information, block line data division information, and block line data position information from the encoded data, the tile data division information indicating whether the encoded data is composed of tile data items that serve as encoded data items of the tiles, the tile data position information indicating positions of the tile data items, the block line data division information indicating whether each tile data item is composed of first block line data and second block line data, the first block line data serving as encoded data of a first block line that is a set of blocks arranged linearly, the second block line data serving as encoded data of a second block line next to the first block line, the block line data position information indicating a position of the second block line data;   a first decoding unit configured to decode the first block line data based on the information derived by the deriving unit; and   a second decoding unit configured to decode the second block line data based on the information derived by the deriving unit and decoding information obtained by decoding encoded data of a block in a predetermined position belonging to the first block line.   
     
     
         2 . The apparatus according to  claim 1 , wherein the position of data of the zeroth block line belonging to the Nth (N is greater than or equal to 1) tile in the frame is indicated by the Nth tile data position information and positions of data items of the Mth (M is greater than or equal to 1) block line and subsequent block lines are indicated as block line data position information by the size of encoded data of the (M−1)th block line. 
     
     
         3 . An image decoding apparatus that decodes encoded data obtained by dividing a frame of image data into rectangular tiles and encoding the image data on a tile-by-tile basis, the apparatus comprising:
 a deriving unit configured to derive tile data division information, block line data division information, and size information from the encoded data, the tile data division information indicating whether the encoded data is composed of first tile data and second tile data, the first and the second tile data serving as encoded data of a corresponding tile, the block line data division information indicating whether each tile data item is composed of first block line data and second block line data, the first block line data serving as encoded data of a first block line that is a set of blocks arranged linearly, the second block line data serving as encoded data of a second block line next to the first block line, the size information indicating a size of the first tile data or the first block line data;   a first decoding unit configured to decode the first block line data based on the information derived by the deriving unit;   a second decoding unit configured to decode the second block line data based on the information derived by the deriving unit and decoding information obtained by decoding encoded data of a block in a predetermined position belonging to the first block line; and if the encoded data is encoded with tile data division and the tile data is encoded without block line data division, the size information indicates the first tile data size, otherwise, the size information indicates the first block line data size.   
     
     
         4 . The apparatus according to  claim 3 , wherein if the encoded data is encoded with tile data division and the tile data is encoded with block line division, the position of Mth (M is greater than or equal to 1) block line data from 0th block line data is derived from sum of information from 0th to (M−1)th block line data size and the position of Nth (N is greater than or equal to 1) tile data from 0th tile data is derived from sum of block data size information of corresponding block data in 0th to (N−1)th tile data. 
     
     
         5 . A method of image decoding for an image decoding apparatus that decodes encoded data obtained by dividing a frame of image data into rectangular tiles and encoding the image data on a tile-by-tile basis, the method comprising the steps of:
 deriving tile data division information, tile data position information, block line data division information, and block line data position information from the encoded data, the tile data division information indicating whether the encoded data is composed of tile data items that serve as encoded data items of the tiles, the tile data position information indicating positions of the tile data items, the block line data division information indicating whether each tile data item is composed of first block line data and second block line data, the first block line data serving as encoded data of a first block line that is a set of blocks arranged linearly, the second block line data serving as encoded data of a second block line next to the first block line, the block line data position information indicating a position of the second block line data;   decoding the first block line data based on the derived information; and   decoding the second block line data based on the derived information and decoding information obtained by decoding encoded data of a block in a predetermined position belonging to the first block line.   
     
     
         6 . A recording medium storing a program that allows a computer to function as the image decoding apparatus according to  claim 1  when read and executed by the computer.