Video encoding method and apparatus using transformation unit of variable tree structure, and video decoding method and apparatus

• US 9,674,553 B2
• Filed: 08/17/2011
• Issued: 06/06/2017
• Est. Priority Date: 08/17/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Tammy, Han, Woo-jin
• Primary Examiner(s): Czekaj, Dave
• Assistant Examiner(s): SULLIVAN, TYLER
• Application Number:
  US13/817,724
• Publication Number:
  US 20130148739A1
• Time in Patent Office: 2,120 Days
• Field of Search: None
• CPC Class Codes: H04N 19/119 Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
• CPC Class Codes: H04N 19/122 Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/174 the region being a slice, e.g. a line of blocks or a group of blocks
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/1883 the unit relating to sub-band structure, e.g. hierarchical level, directional tree, e.g. low-high [LH], high-low [HL], high-high [HH]
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/96 Tree coding, e.g. quad-tree coding

Abstract

A video encoding method is provided. The method includes: encoding a current region of a video by performing a transformation on the current region by using transformation units in a variable tree-structure which are determined from among transformation units that are hierarchically split from a base transformation unit with respect to the current region and which are generated based on a maximum split level of a transformation unit. The method further includes outputting encoded data of the current region, information about an encoding mode, and transformation-unit hierarchical-structure information including maximum size information and minimum size information of the transformation unit with respect to the video.

Claims

1. A video decoding method, performed by at least one processing device, the method comprising:

obtaining, from a bitstream, maximum split information for an intra mode, maximum split information for an inter mode, information about a prediction mode for a current coding unit, and partition mode information for the current coding unit in the intra mode, the partition mode information indicating whether at least one prediction unit is determined by halving a height and a width of the current coding unit in the intra mode;

determining the at least one prediction unit by splitting the current coding unit based on at least one of the information about the prediction mode and the partition mode information;

generating prediction data of the current coding unit by performing prediction based on the at least one prediction unit;

when the information about the prediction mode indicates the intra mode, determining a maximum split level of a transformation unit based on the maximum split information for the intra mode and whether the partition mode information indicates N×

N or 2N×

2N, wherein the transformation unit is determined from the current coding unit, and the maximum split information for the intra mode is information about the transformation unit which the current coding unit predicted in the intra mode is split into;

when the information about the prediction mode indicates the inter mode, determining a maximum split level of a transformation unit based on the maximum split information for the inter mode, wherein the transformation unit is determined from the current coding unit and the maximum split information for the inter mode is information about the transformation unit which the current coding unit predicted in the inter mode is split into;

when a current split level of a current transformation unit is not less than the maximum split level, performing inverse-transformation on the current transformation unit to generate residual data corresponding to the current transformation unit;

when the current split level of the current transformation unit is less than the maximum split level, obtaining sub-split information about the current transformation unit from the bitstream, wherein the current transformation unit is determined from the current coding unit;

when the sub-split information indicates a split of the current transformation unit, splitting the current transformation unit into transformation units of a next split level, wherein the next split level is greater than the current split level;

when the sub-split information indicates a non-split of the current transformation unit, performing inverse-transformation on the current transformation unit to generate the residual data corresponding to the current transformation unit; and

reconstructing the current coding unit by using the prediction data and the residual data.

2. The video decoding method of claim 1, wherein the maximum split information indicates a maximum number of available splits for generating the transformation unit by splitting the current coding unit.

3. The video decoding method of claim 1, wherein a minimum size of the transformation unit determined from the coding unit based on the maximum split level of the transformation unit is not less than a minimum size of a transformation unit according to minimum size information of transformation unit obtained from the bitstream or a size of a transformation unit at a lowermost level obtained by splitting the coding unit to the maximum split level.