Scene-Based Audio Rotation for Orientation-Dependent Coding

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Solution Overview

Problem

Existing scene-based audio coding techniques result in audio quality degradation due to orientation-dependent downmixing, particularly when dominant sound components are not aligned with the directional preference of the coding scheme, leading to inaccurate reconstruction and spatial distortions.

Innovation Solution

Rotate sound components to align with the directional preference of the coding scheme, encoding the rotated components along with rotation parameters, and reversing the rotation at the decoder to maintain high sound quality and accurate sound source positioning even at lower bit rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If orientation-dependent downmixing is used to reduce bit rate, then encoding efficiency is improved, but audio quality and spatial accuracy deteriorate when sound components are not aligned with directional preference

Engineering Contradiction:
Improveencoding efficiencyVSAvoidspatial accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary rotation to sound components before encoding, aligning them with the directional preference of the coding scheme. This pre-alignment ensures that when orientation-dependent downmixing is applied, the dominant sound components are already positioned optimally, preventing spatial inaccuracies and maintaining high audio quality while achieving efficient compression

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If dominant sound components are not aligned with coding scheme directional preference, then encoding can proceed without rotation, but audio quality and sound source positioning accuracy deteriorate

Engineering Contradiction:
Improveencoding process simplicityVSAvoidsound source positioning accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent introduces dynamic rotation parameters that are determined based on the spatial distribution of sound components. The rotation amount is dynamically adjusted to align dominant components with the coding scheme's directional preference, ensuring optimal spatial accuracy while maintaining encoding efficiency. The decoder applies corresponding inverse rotation to reconstruct the original spatial positions accurately

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4256554B1Rotation of sound components for orientation-dependent coding schemes
Publication Date: 2026.01.28 DOLBY LABORATORIES LICENSING CORP
  • EP4256554B1 patent drawingFigure 1A~1B
  • EP4256554B1 patent drawingFigure 2
  • EP4256554B1 patent drawingFigure 3

AI summary

Method for encoding scene-based audio is provided. In some implementations, the method involves determining, by an encoder, a spatial direction of a dominant sound component in a frame of an input audio signal. In some implementations, the method involves determining rotation parameters based on the determined spatial direction and a direction preference of a coding scheme to be used to encode the input audio signal. In some implementations, the method involves rotating sound components of the frame based on the rotation parameters such that, after being rotated, the dominant sound component has a spatial direction that aligns with the direction preference of the coding scheme. In some implementations, the method involves encoding the rotated sound components of the frame of the input audio signal using the coding scheme in connection with an indication of the rotation parameters or an indication of the spatial direction of the dominant sound component.