Method and apparatus for encoding/decoding image using variable-size macroblocks

Abstract

A video encoding apparatus includes a candidate block type configuration unit for configuring block type candidates for encoding an image by using variable sized macroblocks; a video encoder for encoding an input image for each block type candidate; and a block type determiner for determining a block type based on encoding costs by the block type candidate, and generating a bitstream including image data encoded by the determined block type and information for the determined block type. Determining the block type to match the image characteristics enables combinations of diverse modes such as a large block and macroblock size, a minimum subblock size, available divisional block type, prediction mode type within a macroblock, and so on to achieve more effective encoding and decoding of high resolution images.

1 . A video encoding/decoding apparatus, comprising:
 a video encoder for configuring block type candidates for encoding an image by using variable sized macroblocks, encoding an input image by each block type candidate, determining a block type based on encoding costs for each block type candidate, and generating a bitstream including an image data encoded by a determined block type and a information for the determined block type; and   a video decoder for extracting an information for the block type for encoding the image by using variable sized macroblocks and an encoded image data from the bitstream, and generating a reconstructed image by decoding the encoded image data depending on the block type identified by the information for the block type.   
     
     
         2 . (canceled) 
     
     
         3 . A video decoding apparatus comprising:
 a video decoder for extracting an information for a block type for encoding an image by using variable sized macroblocks and encoded image data from a bitstream, and generating a reconstructed image by decoding the encoded image data depending on a block type identified by the information for the block type.   
     
     
         4 . (canceled) 
     
     
         5 . A video encoding method comprising:
 configuring block type candidates for encoding an image by using variable sized macroblocks;   encoding an input image for each block type candidate;   determining a block type based on encoding costs for each block type candidate; and   generating a bitstream including an image data encoded in a determined block type and an information for the determined block type.   
     
     
         6 . The video encoding method of  claim 5 , wherein the block type comprises one or more of a macroblock size corresponding to an encoding and/or a decoding unit, a minimum subblock size, and a subblock mode combination. 
     
     
         7 . The video encoding method of  claim 5 , wherein, the step of configuring the block type candidates configures input block type candidates or determines and configures a block type candidate according to characteristics of the input image. 
     
     
         8 . (canceled) 
     
     
         9 . The video encoding method of  claim 5 , wherein the block type candidates are differently configured according to an intra prediction or an inter prediction, when the block type is a subblock mode combination. 
     
     
         10 . (canceled) 
     
     
         11 . The video encoding method of  claim 5 , wherein a macroblock size is variably selected based on resolution of the input image or image characteristics. 
     
     
         12 . The video encoding method of  claim 5 , wherein a minimum subblock size is variably selected based on a macroblock size. 
     
     
         13 . The video encoding method of  claim 5 , wherein a subblock mode combination within a macroblock is selected based on a macroblock size and a minimum subblock size. 
     
     
         14 . The video encoding method of  claim 5 , wherein a macroblock size is transmitted to a video decoding apparatus by unit of sequences, pictures, slices, or macroblocks. 
     
     
         15 . The video encoding method of  claim 5 , wherein a reference macroblock size is set, and a flag indicating whether to use the reference macroblock size is encoded in each every header of picture, slice header, or macroblock header of the input image and transmitted to a video decoding apparatus. 
     
     
         16 - 28 . (canceled) 
     
     
         29 . A video decoding method comprising:
 extracting an information for a block type for encoding an image by using variable sized macroblocks and an encoded image data from a bitstream; and   generating a reconstructed image by decoding the encoded image data depending on a block type identified by the information for the block type.   
     
     
         30 . The video decoding method of  claim 29 , wherein the block type comprises one or more of a macroblock size corresponding to an encoding and/or a decoding unit, a minimum subblock size, and a subblock mode combination. 
     
     
         31 . The video decoding method of  claim 29 , wherein the extracting step may extract the information for the determined block type from the bitstream once or in every picture of an input image. 
     
     
         32 . The video decoding method of  claim 29 , wherein, when a flag indicating whether to transmit an information for a macroblock size is included in the bitstream, the flag indicating whether to transmit the information for the macroblock size is decoded in an arranged position of a sequence header, a header of each picture, or a slice header. 
     
     
         33 . The video decoding method of  claim 29 , wherein a reference macroblock size agreed with an encoder is set, and a flag indicating whether to use the reference macroblock size is decoded from a header of each picture, a slice header, or a macroblock header. 
     
     
         34 . The video decoding method of  claim 29 , wherein, after extracting from the bitstream a flag indicating whether to use a reference macroblock size and/or additional information indicating an enlargement or a reduction by a predetermined ratio with respect to the reference macroblock size, a current macroblock size is determined by using an extracted flag and/or extracted additional information. 
     
     
         35 . The video decoding method of  claim 29 , wherein, after decoding macroblock block size information, a macroblock size required for a first picture decoding is obtained by using decoded macroblock size information. 
     
     
         36 . The video decoding method of  claim 29 , wherein a macroblock size according to a picture type is set by extracting macroblock sizes of an intra picture and an inter picture from a position within the bitstream agreed with an encoder, respectively. 
     
     
         37 . The video decoding method of  claim 29 , wherein, when a flag indicating whether to transmit information for a minimum subblock size is included in the bitstream, the flag indicating whether to transmit the information on the minimum subblock size is decoded in an arranged position of a sequence header, a header of each picture, or a slice header. 
     
     
         38 . The video decoding method of  claim 29 , wherein a size agreed with an encoder is set as a reference minimum subblock size, and a flag indicating whether to use the reference minimum subblock size is decoded from a header of each picture, a slice header, or a minimum subblock header. 
     
     
         39 . The video decoding method of  claim 29 , wherein, after extracting from the bitstream a flag indicating whether to use a reference minimum subblock size and/or additional information indicating an enlargement or a reduction by a predetermined ratio with respect to the reference minimum subblock size, a current minimum subblock size is extracted by using the information. 
     
     
         40 . The video decoding method of  claim 29 , wherein, when a flag indicating whether to use a reference minimum subblock size and the reference minimum subblock size are not used, a minimum subblock size information is decoded and then a minimum subblock size required for a first picture decoding is obtained by using a decoded minimum subblock size information. 
     
     
         41 . The video decoding method of  claim 29 , wherein a minimum subblock size according to a picture type is set by extracting minimum subblock sizes of an intra picture and an inter picture from a position within the bitstream agreed with an encoder. 
     
     
         42 . The video decoding method of  claim 29 , wherein a flag indicating whether to select and use a combination of subblocks for a prediction or a transform is decoded in a sequence header or a header of each picture, and a basic subblock combination mode agreed with an encoder is used in a prediction or a transform when a value of a decoded flag indicates that the combination of subblocks is not selected and used.