Intra prediction method of chrominance block using luminance sample, and apparatus using same

Patent metadata

Field	Value
Publication number	US-9530224-B2
Application number	US-201214000900-A
Country	US
Kind code	B2
Filing date	Mar 6, 2012
Priority date	Mar 6, 2011
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

Disclosed are an intra prediction method of a chrominance block using a luminance sample and an apparatus using the same. An image decoding method comprises the steps of: calculating an intra prediction mode of a chrominance block on the basis of an LM mapping table when the chrominance block uses an LM; and generating a prediction block for the chrominance block on the basis of the calculated intra prediction mode of the chrominance block. When intra prediction mode information of chrominance blocks are decoded, mutually different tables are used depending on whether or not an LM is used, so that encoding and decoding can be performed without an unnecessary waste of bits.

First claim

The invention claimed is:

1. A video decoding method comprising
receiving a;
bitstream including prediction type information, the prediction type information indicating a current block is coded in an intra mode;
obtaining information on a luma intra prediction mode of the current block;
obtaining index information on the current block based on a bin string obtained from the video signal, the index information being used to specify a chroma intra prediction mode;
deriving the chroma intra prediction mode based on the index information and the luma intra prediction mode;
deriving a prediction chroma sample of the current block based on the chroma intra prediction mode; and
reconstructing a chroma sample based on the derived prediction sample,
wherein the index information indicates one of five values, and
wherein, when the index information indicates a first value among the five values, the chroma intra prediction mode is derived as a planar mode if the luma intra prediction mode is not the planar mode, and the chroma intra prediction mode is derived as an upper right direction diagonal mode if the luma intra prediction mode is the planar mode.

2. The video decoding method according to claim 1 , wherein when the index information indicates a second value among the five values, the chroma intra prediction mode is derived as a vertical mode if the luma intra prediction mode is not the vertical mode, and the chroma intra prediction mode is derived as the upper right direction diagonal mode if the luma intra prediction mode is the vertical mode.

3. The video decoding method according to claim 2 , wherein, when the index information indicates a third mode value among the five values, the chroma intra prediction mode is derived as a horizontal mode if the luma intra prediction mode is not the horizontal mode and the chroma intra prediction mode is derived as the upper right direction diagonal mode if the luma intra prediction mode is the horizontal mode.

4. The video decoding method according to claim 3 , wherein when the index information indicates a fourth value among the five values, the chroma intra prediction mode is derived as a DC mode if the luma intra prediction mode is not the DC mode and the chroma intra prediction mode is derived as the upper right direction diagonal mode representing a diagonal direction to a top right side of the current block when if the luma intra prediction mode is the DC mode.

5. The video decoding method according to claim 1 , wherein the index information is obtained based on a bin string obtained from the bitstream, and
wherein the bin string is one of bin strings of the five values, bin string of the first value, a second value, a third value, and a fourth value, and a fifth value among the five values are represented by ‘100’, ‘101’, ‘110’, ‘111’ and ‘0’, respectively.

6. The video decoding method according to claim 4 , wherein when the index information indicates a fifth value among the five values, the chroma intra prediction mode is derived same as the luma intra prediction mode.

Assignees

• Jeon Yong Joon
• Park Seung Wook
• Lim Jae Hyun
• Kim Jung Sun
• Park Joon Young
• Choi Young Hee
• Sung Jae Won
• Jeon Byeong Moon
• Lg Electronics Inc

Inventors

• Jeon Yong Joon
• Park Seung Wook
• Lim Jae Hyun
• Kim Jung Sun
• Park Joon Young
• Choi Young Hee
• Sung Jae Won
• Jeon Byeong Moon

Classifications

• H04N19/70

  characterised by syntax aspects related to video coding, e.g. related to compression standards · CPC title

• H04N19/16

  for a given display mode, e.g. for interlaced or progressive display mode · CPC title

• H04N19/593 Primary

  involving spatial prediction techniques · CPC title

• H04N19/186

  the unit being a colour or a chrominance component · CPC title

• H04N19/132

  Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking · CPC title