CABAC Binary Arithmetic Decoder With Parallel Renormalization

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Solution Overview

Problem

Conventional CABAC decoders perform sequential processing, leading to long processing times due to repeated renormalization loops, which hinders the speed and efficiency of decoding encoded data.

Innovation Solution

The CABAC decoder architecture includes parallel renormalization processing units for LPS and MPS, allowing renormalization to commence without waiting for LPS/MPS determination completion, thereby reducing processing time and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If sequential processing is used for LPS/MPS determination followed by renormalization, then processing order is simple and easy to implement, but decoding speed is slow due to repeated renormalization loops

Engineering Contradiction:
Improvedecoding speedVSAvoiddecoder architecture complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent performs renormalization processing in advance before LPS/MPS determination is complete. Multiple renormalization processing units (151-156) are activated simultaneously, with some units performing renormalization based on preliminary assumptions about LPS/MPS outcomes. This allows renormalization to overlap with determination processing, reducing total decoding time despite increased architectural complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent divides the renormalization function into multiple independent processing units (151-156), each capable of handling different renormalization scenarios simultaneously. These units are segmented by their specific functions: some handle LPS cases, others handle MPS cases, and they operate in parallel to process different data streams independently

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If renormalization processing loops are repeated to ensure accurate decoding, then decoding accuracy is maintained, but processing time increases significantly

Engineering Contradiction:
Improvedecoding accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent maintains continuous useful action by overlapping renormalization processing with LPS/MPS determination processing. Instead of waiting for determination to complete before starting renormalization, the system continues renormalization operations throughout the determination process, eliminating idle time while maintaining decoding accuracy through multiple parallel processing units

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent performs preliminary renormalization actions before LPS/MPS determination is complete. Renormalization processing units 151-156 execute renormalization based on current state information, and subsequent units verify and adjust results. This preliminary action reduces the need for extensive repeated loops while maintaining accuracy

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3598647B1Binary arithmetic decoder and binary arithmetic decoding device
Publication Date: 2023.06.28 NTT ELECTORNICS CORP
  • EP3598647B1 patent drawingFigure 1
  • EP3598647B1 patent drawingFigure 2
  • EP3598647B1 patent drawingFigure 3

AI summary

To realize an increase in speed and improvement of efficiency of CABAC decoding processing. A binary arithmetic device 1 includes an LPS/MPS determining unit 13 that determines, using a context variable, a range length, and an offset, whether a code is an inferior probability code or a superior probability code, a renormalization processing unit that performs renormalization processing on the range length and the offset, and a context-variable calculating unit that derives the binary data of the code using a determination result and updates the context variable according to the determination result. The renormalization processing unit 15 includes a first renormalizing unit 151 that, in parallel to determination processing of the LPS/MPS determining unit 13, regards the code as the inferior probability code and performs renormalization processing, a second renormalizing unit 152 that, in parallel to the determination processing of the LPS/MPS determining unit 13, regards the code as the superior probability code and performs renormalization processing, and a selecting unit 153 that selects, according to the determination result, an output of the first renormalizing unit 151 or an output of the second renormalizing unit 152.