	US 12,075,092 B2
	Video data encoding and decoding
Karl James Sharman, Basingstoke (GB); Adrian Richard Browne, Basingstoke (GB); and Stephen Mark Keating, Basingstoke (GB)
Assigned to SONY GROUP CORPORATION, Tokyo (JP)
Appl. No. 17/907,208
Filed by SONY GROUP CORPORATION, Tokyo (JP)
PCT Filed Mar. 12, 2021, PCT No. PCT/GB2021/050628 § 371(c)(1), (2) Date Sep. 23, 2022, PCT Pub. No. WO2021/198641, PCT Pub. Date Oct. 7, 2021.
Claims priority of application No. 2004959 (GB), filed on Apr. 3, 2020.
Prior Publication US 2023/0103877 A1, Apr. 6, 2023
Int. Cl. H04N 19/00 (2014.01); H04N 19/122 (2014.01); H04N 19/157 (2014.01); H04N 19/18 (2014.01); H04N 19/625 (2014.01); H04N 19/60 (2014.01)

CPC H04N 19/625 (2014.11) [H04N 19/122 (2014.11); H04N 19/157 (2014.11); H04N 19/18 (2014.11); H04N 19/60 (2014.11)]

12 Claims

1. A video data encoding method for encoding an array of video data values, the method comprising:

frequency-transforming, via circuitry, the video data values according to a frequency transform, to generate an array of frequency-transformed values by a matrix-multiplication process using a transform matrix having a data precision of fourteen bits, the frequency transform being a discrete cosine transform;

defining a 64×64 transform matrix M₆₄for a 64×64 DCT transform; and

for an N×N transform where N is 2, 4, 8 or 16, subsampling the 64×64 transform matrix M₆₄to select a subset of N×N values, the subset M_N[x][y] of values being defined by:

M_N[x][y]=M₆₄[x][(2^(6-log2(N)))y] for x,y=0 . . . (N−1), wherein

the 64×64 transform matrix M₆₄is defined by four quadrants including an upper left quadrant, an upper right quadrant to the right of the upper left quadrant, a lower left quadrant below the upper left quadrant, and a lower right quadrant to the right of the lower left quadrant and below the upper right quadrant,

values of the upper left quadrant are defined by:

values of the upper right quadrant are defined by:

values of the lower left quadrant are defined by:

values of the lower right quadrant are defined by:

and

each different combination of letters represents a different value.