US 12,149,736 B2
Method, apparatus, and system for encoding and decoding image using LM chroma prediction
Yoonsik Choe, Goyang-si (KR); and Jang Won Choi, Incheon (KR)
Assigned to IDEAHUB INC., Seoul (KR)
Filed by IDEAHUB INC., Seoul (KR)
Filed on Jul. 15, 2022, as Appl. No. 17/865,551.
Application 17/865,551 is a continuation of application No. 16/990,532, filed on Aug. 11, 2020, granted, now 11,425,419.
Application 16/990,532 is a continuation of application No. 16/193,406, filed on Nov. 16, 2018, granted, now 10,798,413, issued on Oct. 16, 2020.
Application 16/193,406 is a continuation of application No. 15/101,780, granted, now 10,158,882, issued on Dec. 18, 2018, previously published as PCT/KR2014/009222, filed on Sep. 30, 2014.
Claims priority of application No. 10-2013-0149075 (KR), filed on Dec. 3, 2013.
Prior Publication US 2023/0043350 A1, Feb. 9, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/593 (2014.01); H04N 19/117 (2014.01); H04N 19/176 (2014.01); H04N 19/182 (2014.01); H04N 19/184 (2014.01); H04N 19/186 (2014.01); H04N 19/82 (2014.01); H04N 19/11 (2014.01)
CPC H04N 19/593 (2014.11) [H04N 19/117 (2014.11); H04N 19/176 (2014.11); H04N 19/182 (2014.11); H04N 19/184 (2014.11); H04N 19/186 (2014.11); H04N 19/82 (2014.11); H04N 19/11 (2014.11)] 7 Claims
OG exemplary drawing
 
1. An image decoding apparatus, comprising:
an entropy-decoder configured to decode information including first information and second information,
wherein the first information indicates whether to use one of a plurality of Linear Model (LM) chroma prediction modes representing that a chroma prediction pixel in a chroma block of a current block is derived by a luma value,
wherein the second information specifies the one of the plurality of LM chroma prediction modes for the current block,
wherein the information is signaled at a block level; and
an intra predictor configured to:
obtain the luma value using a luma pixel corresponding to the chroma prediction pixel, the luma pixel being in a luma block of the current block; and
generate the chroma prediction pixel using the luma value multiplied by a first weight,
wherein, in response to the first information indicating that the one of the plurality of LM chroma prediction modes is used, the one of the plurality of LM chroma prediction modes is specified based on the second information,
wherein the plurality of LM chroma prediction modes comprises a first LM chroma prediction mode and a second LM chroma prediction mode,
wherein, under the first LM chroma prediction mode, the first weight is obtained by using a filtered luma pixel, the filtered luma pixel being obtained by using luma pixels located to a left of the luma block,
wherein, under the second LM chroma prediction mode, the first weight is obtained without using the filtered luma pixel,
wherein the luma value is obtained by further using four neighboring luma pixels adjacent to the luma pixel corresponding to the chroma prediction pixel,
wherein the luma value is obtained by a weighted sum of the luma pixel and the four neighboring luma pixels, and
wherein a ratio between a first coefficient multiplied with the luma pixel and a second coefficient multiplied with the four neighboring luma pixels is 4:1.