Context initialization in entropy coding

US10645388B2 · kind B2 · utility

Assignee

• GE Video Compression, LLC · US

Inventors

• Valeri George · Berlin, DE
• Benjamin Bross · Berlin, DE
• Heiner Kirchhoffer · Berlin, DE
• Detlev Marpe · Berlin, DE
• Tung Nguyen · Berlin, DE
• Matthias Preiss · Berlin, DE
• Mischa Siekmann · Berlin, DE
• Jan Stegemann · Berlin, DE
• Thomas Wiegand · Berlin, DE

Key dates

• Filing date: Jun 26, 2019
• Grant date: May 5, 2020
• Expiry date: Jun 26, 2039

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N19/91
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A decoder includes an entropy decoder configured to derive a number of bins of the binarizations from the data stream using binary entropy decoding by selecting a context among different contexts and updating probability states associated with the different contexts, dependent on previously decoded portions of the data stream; a desymbolizer configured to debinarize the binarizations of the syntax elements to obtain integer values of the syntax elements; a reconstructor configured to reconstruct the video based on the integer values of the syntax elements using a quantization parameter, wherein the entropy decoder is configured to distinguish between 126 probability states and to initialize the probability states associated with the different contexts according to a linear equation of the quantization parameter, wherein the entropy decoder is configured to, for each of the different contexts, derive a slope and an offset of the linear equation from first and second four bit parts of a respective 8 bit initialization value.