US 12,348,780 B2
Block-level window size update for arithmetic coding
Xin Zhao, San Jose, CA (US); Madhu Peringassery Krishnan, Mountain View, CA (US); and Shan Liu, Sunnyvale, CA (US)
Assigned to Tencent America LLC, Palo Alto, CA (US)
Filed by TENCENT AMERICA LLC, Palo Alto, CA (US)
Filed on Nov. 30, 2022, as Appl. No. 18/060,259.
Claims priority of provisional application 63/306,849, filed on Feb. 4, 2022.
Prior Publication US 2023/0254511 A1, Aug. 10, 2023
Int. Cl. H04N 19/70 (2014.01); H04N 19/176 (2014.01); H04N 19/91 (2014.01)
CPC H04N 19/70 (2014.11) [H04N 19/176 (2014.11); H04N 19/91 (2014.11)] 17 Claims
OG exemplary drawing
 
1. A method for window size updates when decoding a video stream, the method comprising:
receiving a coded video stream comprising a number of syntaxes and a number of symbols associated with the syntaxes;
determining a count for the number of syntaxes when updating a window size;
determining a number of symbols associated with the syntaxes;
calculating a probability update rate as a function of the determined count for an associated syntax and of the determined number of symbols associated with the syntaxes, wherein a value of the count has a pre-defined value at block-level;
restarting the value of the count with the pre-defined value at one of following levels: a prediction unit (PU) level, a transform unit (TU) level, a coding tree unit (CTU) level; and
updating a context corresponding to the associated syntax at the calculated probability update rate.