Higher Order Ambisonic Audio Renderer Symmetry Information

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Solution Overview

Problem

Current audio rendering technologies lack the ability to consistently convey the artistic intent of higher-order ambisonic audio content across different speaker configurations, leading to inconsistent playback experiences.

Innovation Solution

The specification of audio rendering information in a bitstream allows playback devices to render audio content according to the intended configuration, using spherical harmonic coefficients and rendering matrices to ensure accurate reproduction of the soundfield across various speaker setups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If audio content is rendered using a specific renderer during production, then the artistic intent can be tailored for target speaker configurations, but the playback experience becomes inconsistent across different speaker configurations

Engineering Contradiction:
Improverendering precisionVSAvoidspeaker configuration adaptability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent copies the production renderer's processing logic and parameters into the playback device. The bitstream contains rendering information that replicates the sound engineer's rendering process, allowing the playback device to reproduce the intended soundfield without requiring the exact same physical speaker configuration. This copying approach preserves artistic intent while enabling adaptability to different playback environments.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The rendering information is prepared in advance during the audio content production phase and embedded in the bitstream. This preliminary action includes calculating and storing the rendering parameters, spherical harmonic coefficients, and other processing information that will be needed during playback, eliminating the need for real-time rendering decisions and ensuring consistent artistic intent across different configurations.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If rendering information is provided in the bitstream, then playback consistency improves, but the bitstream complexity and data size increase

Engineering Contradiction:
Improveplayback consistencyVSAvoidbitstream structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential rendering information needed for consistent playback from the complex rendering process. Instead of embedding entire renderer configurations or processing algorithms, the bitstream contains selectively extracted parameters such as spherical harmonic coefficients, rendering mode indicators, and key processing information. This extraction approach maintains playback consistency while minimizing bitstream complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms complex rendering information into simplified parameters suitable for bitstream transmission. Rendering matrices and processing logic are converted into compact parameter representations that can be efficiently encoded and transmitted. This parameter transformation maintains the essential information needed for consistent playback while significantly reducing the data burden on the bitstream.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If higher-order ambisonic processing is used, then soundfield accuracy improves, but the computational requirements and processing complexity increase

Engineering Contradiction:
Improvesoundfield accuracyVSAvoidcomputational power
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent applies higher-order ambisonic processing selectively based on the content requirements and playback capabilities. The rendering information in the bitstream indicates the appropriate processing order and complexity level needed for each audio content, allowing partial application of computationally intensive algorithms only when necessary for artistic intent or content quality, rather than universally applying maximum processing power.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3149972B1Obtaining symmetry information for higher order ambisonic audio renderers
Publication Date: 2018.08.15 QUALCOMM INC
  • EP3149972B1 patent drawingFigure 1
  • EP3149972B1 patent drawingFigure 2
  • EP3149972B1 patent drawingFigure 3

AI summary

In general, techniques are described for obtaining audio rendering information in a bitstream. A device configured to render higher order ambisonic coefficients comprising a processor and a memory may perform the techniques. The processor may be configured to obtain sign symmetry information indicative of sign symmetry of a matrix used to render the higher order ambisonic coefficients to generate a plurality of speaker feeds. The memory may be configured to store the sparseness information.