Method and apparatus for encoding video in consideration of scanning order of coding units having hierarchical structure, and method and apparatus for decoding video in consideration of scanning order of coding units having hierarchical structure

Abstract

A method and apparatus for decoding a video and a method and apparatus for encoding a video are provided. The method for decoding the video includes: receiving and parsing a bitstream of an encoded video; extracting, from the bitstream, encoded image data of a current picture of the encoded video assigned to a maximum coding unit, and information about a coded depth and an encoding mode according to the maximum coding unit; and decoding the encoded image data for the maximum coding unit based on the information about the coded depth and the encoding mode for the maximum coding unit, in consideration of a raster scanning order for the maximum coding unit and a zigzag scanning order for coding units of the maximum coding unit according to depths.

What is claimed is: 
     
       1. A method of decoding a video, the method comprising:
 obtaining, from a bitstream, encoded image data of a plurality of maximum coding units, and split information of coding units in a maximum coding unit of the plurality of maximum coding units; 
 decoding the plurality of maximum coding units according to a raster scanning order; and 
 decoding the coding units in the maximum coding unit according to a zigzag scanning order, wherein the coding units include four coding units of a current depth, 
 wherein: 
 the maximum coding unit is spatially split into coding units of depths including at least one of a current depth and a lower depth the current depth or the current depth and a lower depth according to the split information, 
 when the split information indicates a split for the current depth, a coding unit of the current depth is split into four coding units of the lower depth, independently from neighboring coding units, 
 when the split information indicates a non-split for the current depth, one or more prediction units are obtained from the coding unit of the current depth, and 
 the zigzag scanning order on the four coding units of the current depth is a same order as the raster scanning order on the four coding units of the current depth. 
 
     
     
       2. The method of  claim 1  further comprises referring to neighborhood information by checking usability of the neighborhood information, in consideration of a scanning order of the maximum coding unit, and coding units having same coded depth included in the maximum coding unit. 
     
     
       3. The method of  claim 1  further comprises checking usability of the coding units of the maximum coding unit. 
     
     
       4. A method for encoding a video, the method comprising:
 determining a plurality of maximum coding units to encode according to a raster scanning order;   determining coding units of a current depth or a current depth and a lower depth in the maximum coding unit to encode according to a zigzag scanning order, and determining coding units of a depth which is lower than the current depth to encode according to the zigzag scanning order when a coding unit of the current depth is split into coding units of a depth which is lower than the current depth;   generating split information of coding units in a maximum coding unit of the plurality of maximum coding units which indicates whether a coding unit of a first depth is split into coding units of a second depth which is lower than the first depth; and   generating a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit of the plurality of maximum coding units,   wherein the zigzag scanning order indicates an order of an upper-left coding unit, an upper-right coding unit, a lower-left coding unit and a lower-right coding unit according to the raster scan order among neighboring four coding units,   wherein the maximum coding unit is hierarchically split into one or more coding units of depths including the current depth or the current depth and a lower depth,   wherein when the coding unit of the current depth is split into four coding units of the lower depth, independently from a neighboring coding unit, the split information is generated to indicate a split for the current depth,   wherein when one or more prediction units are obtained from the coding unit of the current depth, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth,   wherein the maximum coding unit has a square shape.   
     
     
       5. A non-transitory computer-readable storage medium having stored thereon instructions, when executed by at least one processor, to perform operations to generate image data, the operations comprising:
 determining a plurality of maximum coding units split from an image to encode according to a raster scanning order;   determining coding units of a current depth in the maximum coding unit to encode according to a zigzag scanning order;   determining coding units of a lower depth to encode according to the zigzag scanning order when a coding unit of the current depth is split into coding units of the lower depth;   generating split information of coding units in the maximum coding unit; and   generating a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit of the plurality of maximum coding units,   wherein the zigzag scanning order indicates an order of an upper-left coding unit, an upper-right coding unit, a lower-left coding unit and a lower-right coding unit according to the raster scan order among neighboring four coding units,   wherein the maximum coding unit is hierarchically split into one or more coding units of depths including the current depth or the current depth and a lower depth,   wherein when the coding unit of the current depth is split into four coding units of the lower depth, independently from a neighboring coding unit, the split information is generated to indicate a split for the current depth,   wherein when one or more prediction units are obtained from the coding unit of the current depth, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth, and   wherein the one or more coding units hierarchically split from the maximum coding unit have a square shape.   
     
     
       6. An apparatus for encoding a video, the apparatus comprising:
 a processor configured to determine a plurality of maximum coding units to encode according to a raster scanning order, determine coding units of a current depth in the maximum coding unit to encode according to a zigzag scanning order, and determine coding units of a depth which is lower than the current depth to encode according to the zigzag scanning order when a coding unit of the current depth is split into coding units of a depth which is lower than the current depth, generate split information of coding units in a maximum coding unit of the plurality of maximum coding units which indicates whether a coding unit of a first depth is split into coding units of a second depth which is lower than the first depth, and generate a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit of the plurality of maximum coding units,   wherein the zigzag scanning order indicates an order of an upper-left coding unit, an upper-right coding unit, a lower-left coding unit and a lower-right coding unit according to the raster scan order among neighboring four coding units,   wherein the maximum coding unit is hierarchically split into one or more coding units of depths including the current depth or the current depth and a lower depth,   wherein when the coding unit of the current depth is split into four coding units of the lower depth, independently from a neighboring coding unit, the split information is generated to indicate a split for the current depth,   wherein when one or more prediction units are obtained from the coding unit of the current depth, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth, and   wherein the maximum coding unit has a square shape.   
     
     
       7. A non-transitory computer-readable storage medium having stored thereon instructions, when executed by at least one processor, to perform operations to generate image data, the operations comprising:
 determining a plurality of maximum coding units split from an image to encode according to a raster scanning order;   determining coding units of a current depth in the maximum coding unit to encode according to a zigzag scanning order;   determining coding units of a lower depth to encode according to the zigzag scanning order when a coding unit of the current depth is split into coding units of the lower depth;   generating split information of coding units in the maximum coding unit; and   generating a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit of the plurality of maximum coding units,   wherein the zigzag scanning order indicates an order of an upper-left coding unit, an upper-right coding unit, a lower-left coding unit and a lower-right coding unit according to the raster scan order among neighboring four coding units,   wherein the maximum coding unit is hierarchically split into one or more coding units of depths including the current depth or the current depth and a lower depth,   wherein when the coding unit of the current depth is split into four coding units of the lower depth, independently from a neighboring coding unit, the split information is generated to indicate a split for the current depth,   wherein when the coding unit of the current depth is split into one or more prediction units, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth,   wherein the one or more coding units hierarchically split from the maximum coding unit have a square shape, and   wherein the maximum coding unit has a square shape.   
     
     
       8. A method for encoding a video, the method comprising:
 determining a plurality of maximum coding units to encode according to a raster scanning order;   determining coding units of a current depth in the maximum coding unit to encode according to a zigzag scanning order, and determining coding units of a depth which is lower than the current depth to encode according to the zigzag scanning order when a coding unit of the current depth is split into coding units of a depth which is lower than the current depth;   generating split information of coding units in a maximum coding unit of the plurality of maximum coding units which indicates whether a coding unit of a first depth is split into coding units of a second depth which is lower than the first depth; and   generating a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit of the plurality of maximum coding units,   wherein the zigzag scanning order indicates an order of an upper-left coding unit, an upper-right coding unit, a lower-left coding unit and a lower-right coding unit according to the raster scan order among neighboring four coding units,   wherein the maximum coding unit is hierarchically split into one or more coding units of depths including the current depth or the current depth and a lower depth,   wherein when the coding unit of the current depth is split into four coding units of the lower depth, independently from a neighboring coding unit, the split information is generated to indicate a split for the current depth, and   wherein when one or more prediction units are obtained from the coding unit of the current depth, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth.   
     
     
       9. A non-transitory computer-readable storage medium having stored thereon instructions, when executed by at least one processor, to perform operations to generate image data, the operations comprising:
 determining a plurality of maximum coding units split from an image to encode according to a raster scanning order;   determining coding units of a current depth in the maximum coding to encode according to a zigzag scanning order;   determining coding units of a lower depth to encode according to the zigzag scanning order when a coding unit of the current depth is split into coding units of the lower depth;   generating information about split information of coding units in the maximum coding unit; and   generating a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit,   wherein the zigzag scanning order indicates an order of an upper-left coding unit, an upper-right coding unit, a lower-left coding unit and a lower-right coding unit according to the raster scan order among neighboring four coding units,   wherein the maximum coding unit is hierarchically split into one or more coding units of depths including the current depth or the current depth and a lower depth,   wherein when the coding unit of the current depth is split into four coding units of the lower depth, independently from a neighboring coding unit, the split information is generated to indicate a split for the current depth, and   wherein when one or more prediction units are obtained from the coding unit of the current depth, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth.   
     
     
       10. An apparatus for encoding a video, the apparatus comprising:
 a processor configured to determine a plurality of maximum coding units to encode according to a raster scanning order, determine coding units of a current depth in the maximum coding unit to encode according to a zigzag scanning order, and determine coding units of a depth which is lower than the current depth to encode according to the zigzag scanning order when a coding unit of the current depth is split into coding units of a depth which is lower than the current depth, generate split information of coding units in a maximum coding unit of the plurality of maximum coding units which indicates whether a coding unit of a first depth is split into coding units of a second depth which is lower than the first depth, and generate a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit of the plurality of maximum coding units,   wherein the zigzag scanning order indicates an order of an upper-left coding unit, an upper-right coding unit, a lower-left coding unit and a lower-right coding unit according to the raster scan order among neighboring four coding units,   wherein the maximum coding unit is hierarchically split into one or more coding units of depths including the current depth or the current depth and a lower depth,   wherein when the coding unit of the current depth is split into four coding units of the lower depth, independently from a neighboring coding unit, the split information is generated to indicate a split for the current depth, and   wherein when one or more prediction units are obtained from the coding unit of the current depth, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth.   
     
     
       11. A non-transitory computer-readable storage medium having stored thereon instructions, when executed by at least one processor, to perform operations to generate image data, the operations comprising:
 determining a plurality of maximum coding units split from an image to encode according to a raster scanning order;   determining coding units of a current depth in the maximum coding unit to encode according to a zigzag scanning order;   determining coding units of a lower depth to encode according to the zigzag scanning order when a coding unit of the current depth is split into coding units of the lower depth; and   generating split information of coding units in the maximum coding unit; and   generating a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit,   wherein the zigzag scanning order indicates an order of an upper-left coding unit, an upper-right coding unit, a lower-left coding unit and a lower-right coding unit according to the raster scan order among neighboring four coding units,   wherein the maximum coding unit is hierarchically split into one or more coding units of depths including the current depth or the current depth and a lower depth,   wherein when the coding unit of the current depth is split into four coding units of the lower depth, independently from a neighboring coding unit, the split information is generated to indicate a split for the current depth,   wherein when one or more prediction units are obtained from the coding unit of the current depth, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth, and   wherein the maximum coding unit has a square shape.   
     
     
       12. An apparatus for encoding a video, the apparatus comprising:
 a processor configured to determine a plurality of maximum coding units to encode according to a raster scanning order, and determine coding units in the maximum coding unit to encode according to a zigzag scanning order, generate split information for coding units in a maximum coding unit of the plurality of maximum coding units which indicates whether a coding unit of a first depth is split into coding units of a second depth which is lower than the first depth, and generate a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit of the plurality of maximum coding units,   wherein:   the maximum coding unit is spatially split into the coding units of depths including a current depth or the current depth and a lower depth,   when the coding unit of the current depth is split into four coding units of the lower depth, independently from neighboring coding units, the split information is generated to indicate a split for the current depth,   when one or more prediction units are obtained from a coding unit of the current depth, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth, and   the zigzag scanning order on the four coding units of the lower depth is a same order as the raster scanning order on the four coding units of the lower depth.   
     
     
       13. A non-transitory computer-readable storage medium having stored thereon instructions, when executed by at least one processor, to perform operations to generate image data, the operations comprising:
 determining a plurality of maximum coding units split from an image to encode according to a raster scanning order;   determining coding units in the maximum coding unit to encode according to a zigzag scanning order; and   generating split information of coding units in the maximum coding unit;   generating a bitstream including encoded image data of the plurality of the maximum coding units and the split information of the coding units in the maximum coding unit,   wherein the maximum coding unit is spatially split into the coding units of depths including a current depth or the current depth and a lower depth,   when the coding unit of the current depth is split into four coding units of the lower depth, independently from neighboring coding units, the split information is generated to indicate a split for the current depth,   when one or more prediction units are obtained from a coding unit of the current depth, the split information is generated to indicate a non-split into coding units of the lower depth for the current depth, and   the zigzag scanning order on the four coding units of the lower depth is a same order as the raster scanning order on the four coding units of the lower depth.