Video encoding method and video decoding method

• US 9,131,218 B2
• Filed: 01/31/2014
• Issued: 09/08/2015
• Est. Priority Date: 09/29/2008
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi Maxell Limited (Maxell, Ltd.)
• Inventors: Takahashi, Masashi, Yamaguchi, Muneaki
• Primary Examiner(s): Kim, Hee-Yong
• Application Number:
  US14/169,301
• Publication Number:
  US 20140146888A1
• Time in Patent Office: 585 Days
• Field of Search: 375/240.16
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0673 Single storage device
• CPC Class Codes: G06N 3/04 Architecture, e.g. interconnection topology
• CPC Class Codes: G06N 3/10 Interfaces, programming languages or software development kits, e.g. for simulating neural networks
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/184 the unit being bits, e.g. of the compressed video stream
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/513 Processing of motion vectors
• CPC Class Codes: H04N 19/517 by encoding
• CPC Class Codes: H04N 19/52 by predictive encoding
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

Provided is a video encoding/decoding technique for improving the compression efficiency by reducing the motion vector code amount. In a video decoding process, the prediction vector calculation method is switched from one to another in accordance with a difference between predetermined motion vectors among a plurality of motion vectors of a peripheral block of a block to be decoded and already decoded. The calculated prediction vector is added to a difference vector decoded from an encoded stream so as to calculate a motion vector. By using the calculated motion vector, the inter-image prediction process is executed.

Claims

1. A video decoding method comprising the steps of:

calculating a motion vector based on information decoded from a coded stream; and

performing an inter-prediction process using the motion vector calculated in the motion vector calculating step, wherein the motion vector calculating step includes;

a first process to select a plurality of candidate blocks including decoded blocks located near a block to be decoded, as options to be used for calculating a motion vector of the block to be decoded, and exclude one of the candidate blocks from the options when a difference between motion vectors of the candidate blocks located near the block to be decoded is smaller than a threshold value;

a second process to read out selection information indicating which one of the options is to be selected among the options from the coded stream; and

a third process to calculate the motion vector for the inter-prediction process based on the selection information.