Audio Entropy Coding Context Mapping Across Resolution Switching

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Solution Overview

Problem

Conventional audio coding techniques suffer from sub-optimal coding efficiency when frequent switching occurs between different time or frequency resolutions, leading to a significant loss in coding efficiency due to the resetting of contexts, which results in the selection of sub-optimal codebooks.

Innovation Solution

Implementing a context mapping mechanism that derives new contexts for coefficients with changing resolutions by using interpolation, extrapolation, sub-sampling, or up-sampling of previous context information, allowing for more frequent switching between time or frequency resolutions without compromising coding efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If context resetting is performed when switching between different time or frequency resolutions, then device complexity is reduced and ease of operation is improved, but coding efficiency deteriorates significantly

Engineering Contradiction:

Improveease of context managementVSAvoidcoding efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-establishing multiple codebooks corresponding to different time and frequency resolutions before actual encoding occurs. When a resolution switch is detected, the system activates the pre-prepared codebook appropriate for the new resolution without needing to reset or rebuild context, thereby maintaining coding efficiency while simplifying context management.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If frequent switching between different time or frequency resolutions is enabled, then adaptability to signal characteristics is improved, but coding efficiency deteriorates due to context resetting

Engineering Contradiction:

Improveadaptation to signal characteristicsVSAvoidcoding efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements dynamics by creating a dynamic codebook selection mechanism that automatically adapts to changing signal characteristics. The system monitors signal properties and dynamically selects the most appropriate codebook from multiple pre-prepared options, enabling frequent resolution switching without context resetting. This maintains both high adaptability to signal characteristics and coding efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by varying the codebook selection parameter based on detected signal characteristics. When signal properties change (indicating a need for different time/frequency resolution), the system changes the active codebook parameter rather than resetting the entire context, allowing efficient adaptation to different signal types such as transient vs. stationary audio content.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If context is reset during resolution switching, then device complexity is reduced, but loss of information occurs due to sub-optimal codebook selection

Engineering Contradiction:

Improvecontext management complexityVSAvoidcoding efficiency loss

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12039985B2Audio entropy encoder/decoder with coding context and coefficient selection

Publication Date: 2024.07.16 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

An audio encoder for encoding segments of coefficients, the segments of coefficients representing different time or frequency resolutions of a sampled audio signal, the audio encoder including a processor for deriving a coding context for a currently encoded coefficient of a current segment based on a previously encoded coefficient of a previous segment, the previously encoded coefficient representing a different time or frequency resolution than the currently encoded coefficient. The audio encoder further includes an entropy encoder for entropy encoding the current coefficient based on the coding context to obtain an encoded audio stream.