Arithmetic Bitstream Entry Points for Parallel CABAC Decoding

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Solution Overview

Problem

Existing arithmetic decoding processes, such as context-based adaptive binary arithmetic coding (CABAC), are highly sequential and cannot be easily parallelized, limiting decoding speed.

Innovation Solution

An encoding concept that symbolizes information values into symbol strings, subdivides coding intervals based on probability estimates, and provides entry point information for parallel decoding, allowing multiple decoders to operate on different parts of a bitstream simultaneously.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If arithmetic decoding is performed using a sequential process (CABAC), then decoding accuracy is maintained, but decoding speed is limited

Engineering Contradiction:
Improvedecoding speedVSAvoidcoding procedure complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The bitstream is divided into multiple segments with designated entry points, allowing multiple decoders to process different segments simultaneously. Each segment contains sufficient information (interval width, interval offset, context model states) to enable independent parallel decoding without requiring sequential processing from the beginning of the bitstream.

Inventive Principle:
Principle #1Segmentation

2Productivity

If parallel decoding is implemented, then decoding speed is improved, but entry point information must be added to the bitstream

Engineering Contradiction:
Improvedecoding efficiencyVSAvoidbitstream size
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

Entry point information including interval width, interval offset, and context model states is prepared and inserted into the bitstream during the encoding phase. This preliminary preparation enables decoders to jump directly to specific entry points and begin parallel decoding without requiring additional runtime computation or larger bitstream storage.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20250365014A1Arithmetic encoder for arithmetically encoding and arithmetic decoder for arithmetically decoding a sequence of information values, methods for arithmetically encoding and decoding a sequence of information values and computer program for implementing these methods
Publication Date: 2025.11.27 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • US20250365014A1 patent drawing
  • US20250365014A1 patent drawing
  • US20250365014A1 patent drawing

AI summary

An encoding scheme is provided for arithmetically encoding a sequence of information values into an arithmetic coded bitstream by providing the bitstream with entry point information, allowing for resuming arithmetic decoding of the bitstream from a predetermined entry point onward. A respective decoding scheme is also provided. These encoding and decoding schemes provide more efficient encoding in view of the decoding speed.