Recording medium having recorded thereon coded information using plus and/or minus rounding of images

Patent metadata

Field	Value
Publication number	US-8942492-B2
Application number	US-201414244993-A
Country	US
Kind code	B2
Filing date	Apr 4, 2014
Priority date	Jun 9, 1997
Publication date	Jan 27, 2015
Grant date	Jan 27, 2015

Abstract

Medium having image decoding program effecting: extracting motion vector information, quantized DCT coefficients, and rounding method information from input information; dequantizing quantized DCT coefficients to DCT coefficients; performing inverse DCT conversion on the DCT coefficients to an error image; synthesizing a prediction image of a currently decoded image by performing motion compensation using motion vector information, rounding method information, and a previously decoded reference image; and adding the prediction and error images to obtain a decoded image; wherein motion compensation is performed with half-pixel accuracy using bilinear interpolation to calculate intensity values of chrominance or luminance at points where no pixels exist in the reference image, the interpolation being performable using a positive or negative rounding method, and using a rounding method specified by rounding method information included in coded information of the currently decoded image, in a header section of the coded information of the current image.

First claim

What is claimed is:

1. A computer-readable medium having stored thereon an image decoding program which, when executed by a computer, effects operations comprising:
extracting motion vector information, quantized DCT coefficients, and rounding method information from input information to be decoded;
dequantizing the quantized DCT coefficients to obtain DCT coefficients;
performing inverse DCT conversion on the DCT coefficients to obtain an error image;
synthesizing a predict…

Assignees

• Hitachi Ltd

Inventors

• Nakaya Yuichiro

Classifications

• H04N19/126

  Electricity · mapped topic

• H04N19/115

  Electricity · mapped topic

• H04N19/45

  Electricity · mapped topic

• H04N19/597

  Electricity · mapped topic

• H04N19/177

  Electricity · mapped topic