US 11,695,960 B2
Transform and last significant coefficient position signaling for low-frequency non-separable transform in video coding
Alican Nalci, San Diego, CA (US); Hilmi Enes Egilmez, San Diego, CA (US); Vadim Seregin, San Diego, CA (US); Muhammed Zeyd Coban, Carlsbad, CA (US); and Marta Karczewicz, San Diego, CA (US)
Assigned to QUALCOMM Incorporated, San Diego, CA (US)
Filed by QUALCOMM Incorporated, San Diego, CA (US)
Filed on Jun. 11, 2020, as Appl. No. 16/899,063.
Claims priority of provisional application 62/868,346, filed on Jun. 28, 2019.
Claims priority of provisional application 62/861,828, filed on Jun. 14, 2019.
Prior Publication US 2020/0396487 A1, Dec. 17, 2020
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/645 (2014.01); H04N 19/18 (2014.01); H04N 19/124 (2014.01); H04N 19/70 (2014.01); H04N 19/186 (2014.01); H04N 19/176 (2014.01)
CPC H04N 19/645 (2014.11) [H04N 19/124 (2014.11); H04N 19/176 (2014.11); H04N 19/18 (2014.11); H04N 19/186 (2014.11); H04N 19/70 (2014.11)] 35 Claims
OG exemplary drawing
 
1. A method of decoding video data, the method comprising:
determining, based on a block size of a current block and a low-frequency non-separable transform (LFNST) syntax element, a zero-out pattern of normatively defined zero-coefficients, wherein the LFNST syntax element is signaled at a transform unit (TU) level, wherein a normative restriction limits a last significant coefficient position of the current block to a position in the current block allowed to be non-zero by the determined zero-out pattern;
based on the normative restriction limiting the last significant coefficient position of the current block to the position in the current block allowed to be non-zero by the determined zero-out pattern, inferring that the last significant coefficient position of the current block is in a region of the current block that is not zeroed out by the determined zero-out pattern without syntax elements specifying the last significant coefficient position being signaled in a bitstream that comprises an encoded representation of the video data;
determining transform coefficients of the current block, wherein the transform coefficients of the current block include transform coefficients in an LFNST region of the current block and transform coefficients outside the LFNST region of the current block, and determining the transform coefficients of the current block comprises:
applying an inverse LFNST to determine values of one or more transform coefficients in the LFNST region of the current block; and
determining that transform coefficients of the current block in a region of the current block defined by the zero-out pattern are equal to 0;
applying an inverse transform to the transform coefficients of the current block to determine residual data for the current block; and
reconstructing the current block based on the residual data for the current block.