Spatial Audio Metadata Embedding for Legacy Channel Compatibility

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Solution Overview

Problem

Legacy channel-based audio systems lose spatial information when rendering next generation spatial audio formats, leading to a degradation of the playback experience in spatial audio environments.

Innovation Solution

Incorporating additional metadata derived from the spatial audio format into the channel-based format, which is then processed by an enhanced decoder to recover lost positional information and upmix the audio content for optimal playback in spatial audio environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If spatial audio content is rendered into legacy channel-based format, then compatibility with legacy audio systems is improved, but spatial information is lost

Engineering Contradiction:
Improvecompatibility with legacy audio systemsVSAvoidspatial information
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by embedding metadata containing spatial information into the channel-based audio stream before transmission. This metadata is prepared in advance and inserted into the audio data structure, allowing spatial information to be preserved and recovered during playback without requiring real-time processing or additional transmission bandwidth.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses metadata as an intermediary carrier that bridges the gap between spatial audio content and legacy channel-based systems. The metadata acts as a mediator that transports spatial information through the legacy audio stream, enabling enhanced decoders to recover and utilize this information while maintaining compatibility with standard playback systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If next generation spatial audio format is downmixed to legacy channel-based format, then playback on legacy systems is enabled, but spatial coherence is degraded

Engineering Contradiction:
Improveplayback capability on legacy systemsVSAvoidspatial coherence
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent preserves spatial coherence by pre-calculating and embedding metadata that contains precise spatial positioning information during the downmixing process. This preliminary preparation ensures that when enhanced decoders process the audio, they can accurately reconstruct the spatial relationships between audio objects, maintaining the original spatial coherence intent.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the representation parameters of spatial information by encoding positional data, trajectories, and spatial relationships in metadata rather than relying solely on channel-based spatial cues. This parameter transformation allows spatial information to be preserved in a format that can be accurately interpreted by enhanced decoders, maintaining spatial coherence across different playback configurations.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If audio objects are rendered using parametric source descriptions, then spatial precision is improved, but system complexity increases

Engineering Contradiction:
Improvespatial positioning accuracyVSAvoidprocessing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts spatial information from complex parametric source descriptions and consolidates it into structured metadata fields. By separating spatial parameters (position, trajectory, spatial relationships) from the audio signal and encoding them in a standardized metadata format, the system achieves high spatial precision while reducing processing complexity through organized data representation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms complex parametric source descriptions into simplified metadata parameters that maintain spatial precision. By changing the representation from full parametric models to essential spatial parameters encoded in metadata, the system achieves accurate spatial positioning with reduced computational requirements for both encoding and decoding operations.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2862370B1Rendering and playback of spatial audio using channel-based audio systems
Publication Date: 2017.08.30 DOLBY LABORATORIES LICENSING CORP
  • EP2862370B1 patent drawingFigure 1~2
  • EP2862370B1 patent drawingFigure 3
  • EP2862370B1 patent drawingFigure 4A~4B

AI summary

Embodiments are described for a method and system of rendering and playing back spatial audio content using a channel-based format. Spatial audio content that is played back through legacy channel-based equipment is transformed into the appropriate channel-based format resulting in the loss of certain positional information within the audio objects and positional metadata comprising the spatial audio content. To retain this information for use in spatial audio equipment even after the audio content is rendered as channel-based audio, certain metadata generated by the spatial audio processor is incorporated into the channel-based data. The channel-based audio can then be sent to a channel-based audio decoder or a spatial audio decoder. The spatial audio decoder processes the metadata to recover at least some positional information that was lost during the down-mix operation by upmixing the channel-based audio content back to the spatial audio content for optimal playback in a spatial audio environment.