Method and apparatus for encoding/decoding image

Patent metadata

Field	Value
Publication number	US-9826251-B2
Application number	US-201715489784-A
Country	US
Kind code	B2
Filing date	Apr 18, 2017
Priority date	Oct 17, 2011
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A method for decoding an image, according to the present invention, comprises the steps of: receiving image information that corresponds to a block to be decoded; performing entropy-decoding with respect to the image information that is received; deciding a transform skip mode of the block to be decoded from a plurality of transform skip mode candidates, based on the image information that is entropy-decoded; and reverse-transforming the block to be decoded based on the transform skip mode that is decided.

First claim

The invention claimed is:

1. A method of decoding a video signal having a current block to be decoded with a decoding apparatus, comprising:
obtaining residual samples of the current block;
obtaining prediction samples of the current block;
reconstructing the current block based on the residual samples and the prediction samples; and
applying a deblocking filter to the reconstructed current block,
wherein obtaining the residual samples of the current block comprises:
determining a scanning type of the current block, the scanning type comprising at least one of a vertical scan, a horizontal scan or a zigzag scan;
obtaining residual coefficients relating to the current block based on the determined scanning type;
obtaining inverse-quantized residual coefficients by inverse-quantizing the residual coefficients;
determining, based on a transform skip mode index specifying a transform skip mode of the current block,
wherein the transform skip mode of the current block is determined to be one of one or more transform skip mode candidates,
wherein the one or more transform skip mode candidates include at least one of a 2D transform mode, a horizontal transform mode, a vertical transform mode and a non-transform mode, and
wherein a number of the one or more transform skip mode candidates is different according to a size or a shape of the current block; and
obtaining, based on the determined transform skip mode of the current block, the residual samples from the inverse-quantized residual coefficients,
wherein when the transform skip mode of the current block is determined to be the non-transform mode, the residual samples are obtained by scaling the inverse-quantized residual coefficients in non-transformed rows and/or columns of the current block with a pre-determined value.

2. The method of claim 1 , wherein the scaling is performed using a bit shift operation.

3. The method of claim 1 , wherein the transform skip mode index is transmitted, from an encoding apparatus, by a transform unit, the transform unit being representative of a unit where the inverse-transform is performed for the current block.

4. The method of claim 1 , wherein the 2D transform mode performs both a horizontal transform and a vertical transform, the horizontal transform mode performs the horizontal transform only without the vertical transform, the vertical transform mode performs the vertical transform only without the horizontal transform, and the non-transform mode performs none of the horizontal transform and the vertical transform.

Assignees

• Kt Corp

Inventors

• Lee Bae Keun
• Kwon Jae Cheol
• Kim Joo Young

Classifications

• H04N19/513

  Processing of motion vectors · CPC title

• H04N19/11 Primary

  among a plurality of spatial predictive coding modes · CPC title

• H04N19/124

  Quantisation · CPC title

• H04N19/46 Primary

  Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) · CPC title

• H04N19/61 Primary

  in combination with predictive coding · CPC title