Directional Audio Parameter Encoding with Split Time-Frequency Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current spatial audio coding techniques, such as DirAC, face challenges in achieving low bit-rate transmission of 3D audio data due to high data requirements, particularly in scenarios beyond teleconference settings, where the capability of DirAC is reduced, and assumptions limit the data rate to around 3 kbit/s, which is not generic enough for multiple audio sources and complex noise backgrounds.
Innovation Solution
The proposed solution involves encoding directional audio coding parameters with different resolutions for diffuseness and direction parameters, allowing for lower time or frequency resolutions in diffuseness parameters and higher resolutions in direction parameters, and using weighted averaging and quantization to reduce data while maintaining quality, with specific encoding and decoding processes to adapt precision based on signal power and diffuseness values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DirAC technique is used to represent spatial sound parametrically with high resolution for both diffuseness and direction parameters, then the quality of spatial audio reproduction is improved, but the bit-rate required for transmission increases significantly
Solution Approach 1:
The patent applies different resolutions to different spatial parameters: high resolution for direction parameters (azimuth and elevation) to maintain precise spatial localization, and low resolution for diffuseness parameters to reduce data volume. This local differentiation of quality levels resolves the contradiction by optimizing each parameter's resolution according to its perceptual importance rather than uniformly applying high resolution to all parameters.
Solution Approach 2:
The patent dynamically adjusts the resolution of spatial parameters based on signal characteristics. Direction parameters maintain high resolution across all conditions, while diffuseness parameters switch between high and low resolution modes depending on the audio content and scene complexity, thereby adapting the overall parameter resolution to minimize bit-rate while preserving essential spatial quality.
2Quantity of substance
If DirAC capability is reduced to achieve low data rate transmission (around 3 kbit/s), then the bit-rate is reduced, but the generality of the model is limited and not suitable for multiple audio sources and complex noise backgrounds
Solution Approach 1:
The patent introduces dynamic resolution adjustment for diffuseness parameters based on scene complexity and signal power. In simple scenes with single audio sources, low resolution suffices, maintaining low bit-rate. In complex scenes with multiple sources or noise backgrounds, the system automatically increases diffuseness parameter resolution to preserve spatial accuracy, thereby adapting the model's capability to match the scene requirements without being constrained to a fixed low-resolution mode.
Solution Approach 2:
The patent creates a universal encoding framework that can handle diverse audio scenarios (teleconferencing, music, noise environments, multiple sources) through a single adaptive system. The weighted averaging mechanism and dynamic resolution selection enable the same DirAC model to function effectively across different application domains, eliminating the need for scenario-specific model reductions and achieving both low bit-rate and broad generality.
3Measurement precision
If high resolution is used for both diffuseness and direction parameters, then the spatial audio quality is maintained, but the encoding complexity and computational load increase
Solution Approach 1:
The patent reduces encoding complexity by applying high computational effort only where necessary: direction parameters receive full-resolution processing to maintain accurate spatial localization, while diffuseness parameters use reduced-resolution processing with simpler weighted averaging. This local differentiation of processing intensity significantly reduces overall encoding complexity while preserving critical spatial information.
4Quantity of substance
If low resolution is used for diffuseness parameters, then the bit-rate is reduced, but the accuracy of spatial representation may be compromised
Solution Approach 1:
The patent implements a feedback mechanism where the encoder evaluates scene complexity and signal power, then adjusts diffuseness parameter resolution accordingly. In complex scenes or when spatial accuracy is critical, the system increases diffuseness resolution to prevent quality degradation. This feedback-based adaptive resolution ensures that bit-rate reduction does not permanently compromise accuracy, as the system can dynamically restore precision when needed.
Data Source
Figure 1a
Figure 1b
Figure 2a~2b
AI summary
An apparatus for encoding directional audio coding parameters comprising diffuseness parameters and direction parameters, comprises: a parameter calculator (100) for calculating the diffuseness parameters with a first time or frequency resolution and for calculating the direction parameters with a second time or frequency resolution; and a quantizer and encoder processor (200) for generating a quantized and encoded representation of the diffuseness parameters and the direction parameters.