3D Down-Mix Signal Rendering for Headphone Spatial Audio Recovery
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Solution Overview
Problem
Existing audio signal processing technologies fail to efficiently reproduce multi-channel signals with 3D effects in various reproduction environments, particularly when using 2-channel speakers like headphones, as they lack effective methods to create immersive 3D sound experiences.
Innovation Solution
The proposed solution involves a decoding method and apparatus that extracts and processes 3D down-mix signals using 3D rendering operations to generate and remove 3D effects, allowing for adaptive reproduction of audio signals with optimal sound quality based on the environment, utilizing components like bit unpacking units, 3D rendering units, and multi-channel decoders to manage spatial information and filter coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-channel signals are down-mixed to 2-channel for reproduction on headphones, then compatibility with 2-channel speakers is improved, but 3D sound effects are lost
Solution Approach 1:
The patent applies preliminary 3D rendering operations during the encoding phase to process the down-mixed signal before transmission. This preliminary processing embeds spatial information and 3D effects into the down-mixed signal, allowing the decoder to reconstruct 3D sound fields without requiring the original multi-channel signal, thus preserving 3D effects while maintaining 2-channel compatibility
Solution Approach 2:
The patent changes the parameter representation of spatial information by encoding spatial parameters (such as inter-channel level differences, inter-channel time differences, and spatial position data) alongside the down-mixed signal. These parameter changes enable the decoder to synthesize 3D sound effects from the 2-channel signal by adjusting spatial parameters during playback, thereby recovering 3D effects that would otherwise be lost in standard down-mixing
2Manufacturing precision
If complex 3D processing techniques are applied to preserve 3D effects, then sound quality is improved, but processing complexity increases
Solution Approach 1:
The patent segments the 3D processing into distinct functional modules: a 3D rendering unit that processes the down-mixed signal to extract spatial information, a spatial parameter encoder that compresses spatial data, and a decoder that reconstructs 3D sound fields. This segmentation allows each module to perform a specific function efficiently, reducing overall processing complexity while maintaining high sound quality through specialized optimization of each segment
Solution Approach 2:
The patent introduces spatial parameter data as an intermediary between the down-mixed signal and the final 3D output. Instead of directly processing complex multi-channel signals, the system uses compact spatial parameters as a mediator that captures essential 3D information in a compressed form. This intermediary representation simplifies processing by reducing the dimensionality of the problem while preserving the information needed for high-quality 3D sound reconstruction
Data Source
AI summary
An encoding method and apparatus and a decoding method and apparatus are provided. The decoding method includes extracting a three-dimensional (3D) down-mix signal from an input bitstream, generating a down-mix signal with 3D effects removed therefrom by performing a 3D rendering operation on the extracted 3D down-mix signal, and generating a 3D down-mix signal with 3D effects by performing a 3D rendering operation on the generated down-mix signal. Accordingly, it is possible to efficiently encode multi-channel signals with 3D effects and to adaptively restore and reproduce audio signals with optimum sound quality according to the characteristics of an audio reproduction environment.