US 12,126,806 B2
Arithmetic decoding device, image decoding apparatus, arithmetic coding device, and image coding apparatus
Tomohiro Ikai, Sakai (JP); and Takeshi Tsukuba, Sakai (JP)
Assigned to SHARP KABUSHIKI KAISHA, Sakai (JP)
Filed by Sharp Kabushiki Kaisha, Sakai (JP)
Filed on Jul. 21, 2023, as Appl. No. 18/224,673.
Application 18/224,673 is a continuation of application No. 17/897,880, filed on Aug. 29, 2022, granted, now 11,758,140.
Application 17/897,880 is a continuation of application No. 17/077,490, filed on Oct. 22, 2020, granted, now 11,509,898, issued on Nov. 22, 2022.
Application 17/077,490 is a continuation of application No. 16/596,354, filed on Oct. 8, 2019, granted, now 10,848,764, issued on Nov. 24, 2020.
Application 16/596,354 is a continuation of application No. 15/635,238, filed on Jun. 28, 2017, granted, now 10,491,900, issued on Nov. 26, 2019.
Application 15/635,238 is a continuation of application No. 15/468,142, filed on Mar. 24, 2017, granted, now 9,794,572, issued on Oct. 17, 2017.
Application 15/468,142 is a continuation of application No. 15/341,019, filed on Nov. 2, 2016, granted, now 9,699,479, issued on Jul. 4, 2017.
Application 15/341,019 is a continuation of application No. 14/402,114, granted, now 9,538,205, issued on Jan. 3, 2017, previously published as PCT/JP2013/064447, filed on May 24, 2013.
Claims priority of application No. 2012-126567 (JP), filed on Jun. 1, 2012; and application No. 2012-178842 (JP), filed on Aug. 10, 2012.
Prior Publication US 2023/0362381 A1, Nov. 9, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 11/02 (2006.01); H04N 19/117 (2014.01); H04N 19/124 (2014.01); H04N 19/13 (2014.01); H04N 19/159 (2014.01); H04N 19/176 (2014.01); H04N 19/44 (2014.01); H04N 19/46 (2014.01); H04N 19/513 (2014.01); H04N 19/60 (2014.01); H04N 19/61 (2014.01); H04N 19/70 (2014.01); H04N 19/91 (2014.01)
CPC H04N 19/13 (2014.11) [H04N 19/117 (2014.11); H04N 19/124 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/44 (2014.11); H04N 19/46 (2014.11); H04N 19/513 (2014.11); H04N 19/60 (2014.11); H04N 19/61 (2014.11); H04N 19/70 (2014.11); H04N 19/91 (2014.11)] 24 Claims
OG exemplary drawing
 
1. A method for decoding coded data of a transform unit, the method comprising:
decoding a sub-block coefficient presence/absence flag for a target sub-block of the transform unit indicating whether or not one or more non-zero transform coefficients are included in the target sub-block, the transform unit comprising a plurality of sub-blocks including the target sub-block, a right adjacent sub-block to the target sub-block, and a lower adjacent sub-block to the target sub-block;
when the sub-block coefficient presence/absence flag for the target sub-block indicates that there are one or more non-zero transform coefficients included in the target sub-block, deriving a parameter used to derive a context index for decoding a transform coefficient presence/absence flag indicating whether or not a transform coefficient of the target sub-block is 0, wherein the parameter is derived as follows:
when a sub-block coefficient presence/absence flag for the right adjacent sub-block indicates that there are no non-zero transform coefficients included in the right adjacent sub-block and a sub-block coefficient presence/absence flag for the lower adjacent sub-block indicates that there are no non-zero transform coefficients included in the lower adjacent sub-block,
setting the parameter to a first value in a case where a sum of a horizontal coordinate and a vertical coordinate indicating a position of the transform coefficient of the target sub-block is equal to a first threshold value,
setting the parameter to a second value in a case where the sum of the horizontal coordinate and the vertical coordinate indicating the position of the transform coefficient of the target sub-block is greater than the first threshold and is less than a second threshold value, and
setting the parameter to a third value in a case where the sum of the horizontal coordinate and the vertical coordinate indicating the position of the transform coefficient of the target sub-block is greater than or equal to the second threshold value, and
when the sub-block coefficient presence/absence flag for the right adjacent sub-block indicates that there are one or more non-zero transform coefficients included in the right adjacent sub-block and the sub-block coefficient presence/absence flag for the lower adjacent sub-block indicates that there are one or more non-zero transform coefficients included in the lower adjacent sub-block,
setting the parameter to the first value regardless of the position of the transform coefficient of the target sub-block;
deriving a context index based on the parameter;
identifying a context based on the derived context index; and
decoding the transform coefficient presence/absence flag using the identified context.