US 11,706,413 B2
Unified transform type signaling and transform type dependent transform coefficient level coding
Benjamin Bross, Berlin (DE); Phan Hoang Tung Nguyen, Berlin (DE); Paul Keydel, Berlin (DE); Heiko Schwarz, Berlin (DE); Detlev Marpe, Berlin (DE); Thomas Wiegand, Berlin (DE); and Christian Helmrich, Berlin (DE)
Assigned to Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., Munich (DE)
Filed by Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., Munich (DE)
Filed on Jun. 29, 2021, as Appl. No. 17/362,869.
Application 17/362,869 is a continuation of application No. PCT/EP2019/087162, filed on Dec. 30, 2019.
Claims priority of application No. 19150112 (EP), filed on Jan. 2, 2019; and application No. 19162406 (EP), filed on Mar. 12, 2019.
Prior Publication US 2021/0368176 A1, Nov. 25, 2021
Int. Cl. H04N 19/12 (2014.01); H04N 19/129 (2014.01); H04N 19/132 (2014.01); H04N 19/176 (2014.01); H04N 19/46 (2014.01)
CPC H04N 19/12 (2014.11) [H04N 19/129 (2014.11); H04N 19/132 (2014.11); H04N 19/176 (2014.11); H04N 19/46 (2014.11)] 16 Claims
OG exemplary drawing
 
1. An apparatus for decoding a picture using predictive coding and block-based transform residual coding, comprising:
a processor; and
a memory having instructions which, when executed by the processor, cause the apparatus to:
select, for a predetermined transform block, a transformation out of a predetermined list of transformations, the selected transformation comprising an identity transformation and at least one non-identity transformation,
decode, for the predetermined transform block, a block of coefficients from a data stream by decoding for a current coefficient a significance flag indicative of whether the current coefficient is zero or not using a context, wherein:
when the selected transformation is the identity transformation, the context depends on a number of coefficients being non-zero among a first set of coefficients immediately neighboring the current coefficient, and
when the selected transformation is one of the at least one non-identity transformation, the context depends on values of a second set of coefficients and a position of the current coefficient, the second set of coefficients including at least one coefficient immediately neighboring the current coefficient and at least one coefficient positioned farther away from the current coefficient than any of the coefficients immediately neighboring the current coefficient,
derive from the block of coefficients a residual sample array for the predetermined transform block so that the block of coefficients is related to the residual sample array according to the selected transformation, and
correct a prediction for the predetermined transform block using the residual sample array to reconstruct the predetermined transform block.