Spatial Audio Signal Conversion to B-Format Components
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Solution Overview
Problem
Conventional spatial audio processing methods, such as DirAC, face limitations in reproducing reverberant or ambient sound scenarios with limited quality, especially when using mono DirAC streams, which require additional audio channels for improved quality.
Innovation Solution
Converting a mono DirAC stream into a B-format signal, allowing for processing and rendering directional components, enabling more efficient spatial processing and improved quality by representing spatial audio signals as omnidirectional and directional components, which can be jointly processed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a mono DirAC stream is used for spatial audio reproduction, then transmission efficiency and compactness are improved, but the quality of reverberant and ambient sound scenarios deteriorates
Solution Approach 1:
The invention segments the spatial audio signal into omnidirectional and directional components (B-format signals W, X, Y, Z). This segmentation allows the mono DirAC stream to be decomposed into distinct spatial components that can be independently processed and combined to synthesize high-quality reverberant sound scenarios without requiring multiple transmitted channels.
Solution Approach 2:
The invention introduces B-format signals as an intermediary representation. The mono DirAC stream is converted into B-format signals (omnidirectional W and directional X, Y, Z components), which serve as an intermediate format that enables advanced spatial processing and high-quality reverberation synthesis before final rendering to loudspeakers.
2Manufacturing precision
If additional audio channels are transmitted to improve reverberant sound quality, then sound reproduction quality is improved, but transmission efficiency and data compactness deteriorate
Solution Approach 1:
Instead of transmitting multiple audio channels and reducing them at the receiver, the invention inverts the approach by transmitting a single mono DirAC stream and expanding it into multiple B-format components at the receiver. This inversion maintains transmission efficiency while achieving the quality benefits of multi-channel processing.
3Device complexity
If spatial audio signals are processed in mono DirAC format, then processing simplicity is maintained, but the ability to create and process reverberant effects deteriorates
Solution Approach 1:
The invention performs preliminary conversion of the mono DirAC stream into B-format signals before applying spatial audio effects. By converting to B-format components first, the system enables versatile spatial processing (reverberation, ambient effects, panning) to be applied to the directional components, with results that are then rendered to the final loudspeaker configuration.
Data Source
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AI summary
An apparatus (100) for determining a converted spatial audio signal, the converted spatial audio signal having an omnidirectional audio component (W' ) and at least one directional audio component, from an input spatial audio signal, the input spatial audio signal having an input audio representation (W) and an input direction of arrival (Ø). The apparatus (100) comprises an estimator (110) for estimating a wave representation (W) comprising a wave field measure and a wave direction of arrival measure based on the input audio representation (W) and the input direction of arrival (Ø). The apparatus (100) further comprises a processor (120) for processing the wave field measure and the wave direction of arrival measure to obtain the omnidirectional audio component (W ) and the at least one directional component (X; Y; Z).