Audio Encoding with Constrained Rendering Metadata
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Solution Overview
Problem
Existing audio encoding technologies face challenges in balancing flexibility, quality, and complexity, particularly in dynamic applications like virtual reality, where there is a trade-off between flexibility and audio quality, and they often require increased data rates and reduced flexibility.
Innovation Solution
An audio encoding apparatus that generates an encoded audio data stream with constrained rendering parameters, such as spatial position, gain level, and volume, allowing for flexible rendering while maintaining control from the source side, and includes output metadata to guide the rendering process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If audio encoding allows high flexibility for rendering side adaptation and customization, then rendering flexibility and adaptability are improved, but audio quality deteriorates and complexity increases
Solution Approach 1:
The audio signal is segmented into multiple audio items, each with specific rendering parameters. This segmentation allows independent control and optimization of each audio item while maintaining overall audio quality, resolving the contradiction between rendering flexibility and audio quality.
Solution Approach 2:
The patent applies parameter changes by modifying rendering parameters (such as spatial position, gain, panning) of individual audio items based on listener position and preferences. This enables flexible rendering adaptation without compromising the core audio quality, as the changes are applied selectively to specific parameters rather than the entire audio signal.
2Adaptability or versatility
If audio encoding uses multiple different audio types (channels, objects, scene-based), then adaptability and versatility are improved, but device complexity increases
Solution Approach 1:
The patent implements a universal audio item structure that can represent multiple audio types (channels, objects, scene-based) through a common framework. Each audio item contains type identification and specific parameters that define its behavior, allowing the system to handle diverse audio types without requiring separate complex processing paths for each type.
3Adaptability or versatility
If metadata is provided to represent audio items and their properties, then adaptability for local customization is improved, but data rate increases
Solution Approach 1:
The patent extracts only the essential rendering parameters and audio item properties into metadata, rather than transmitting complete audio signals for every possible rendering scenario. This selective extraction of critical information enables client-side customization while minimizing the amount of metadata that needs to be transmitted, thus reducing data rate overhead.
4Adaptability or versatility
If renderer is given full freedom to adapt audio scene locally, then rendering flexibility is improved, but control from content provider is reduced
Solution Approach 1:
The patent implements dynamic parameter constraints where the renderer's freedom to adapt audio items is adjusted based on content provider specifications. Some audio items have fixed parameters that maintain content provider control, while others have flexible parameters that allow renderer adaptation. This dynamic approach balances renderer freedom with content provider control on a per-parameter basis.
Data Source
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AI summary
An audio encoding apparatus comprises an audio receiver (201) receiving audio items representing an audio scene and a metadata receiver (203) receives input presentation metadata for the audio items describing presentation constraints for the rendering of the audio items. The presentation constraints constrain a rendering parameter that can be adapted when rendering the audio items. An audio encoder (205) generates encoded audio data for the audio scene by encoding the plurality of audio items with the encoding being adapted in response to the input presentation metadata. A metadata circuit (207) generates output presentation metadata from the input presentation metadata. The output presentation metadata comprises data for encoded audio items which constrain the extent by which an adaptable parameter of a rendering can be adapted when rendering the encoded audio items. An output (209) generates an encoded audio data stream comprising the encoded audio data and the output presentation metadata.