Binaural Spatialization Using Decorrelation Cues in Compressed Audio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing binaural sound spatialization techniques fail to effectively utilize decorrelation information between front and back channels, leading to a degradation of spatialization quality and surround effect in 3D audio scenes during binaural restitution.
Innovation Solution
A method that processes sound data by obtaining spatialization parameters to form combinations of filters representing transfer functions between listener ears and loud speakers, including decorrelation between back and front loud speakers, and applying these filters to compressed data for improved binaural or transaural spatialized restitution on two channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binaural synthesis using HRTF transfer functions is used, then spatialization can be achieved on two channels, but decorrelation information between front and back channels is lost, degrading spatialization quality and surround effect
Solution Approach 1:
The patent segments the transfer functions into front and back components, processing them separately to preserve decorrelation information. The front transfer function H_front(ω) and back transfer function H_back(ω) are independently determined and combined with decorrelation factors, allowing the system to maintain spatialization quality while preserving information that would otherwise be lost in conventional mixing approaches.
2Loss of energy
If multi-channel audio signals are compression-encoded on reduced channels for transmission, then bandwidth is reduced, but spatialization information including decorrelation cues may be degraded
Solution Approach 1:
The patent applies preliminary action by determining and storing decorrelation factors (γ_front, γ_back) during the encoding phase, before transmission. These factors are extracted from the multi-channel signal and embedded in the compressed representation, ensuring that spatialization information is preserved in advance and can be efficiently reconstructed during decoding without requiring full multi-channel transmission.
3Ease of manufacture
If front and back channels are simply mixed for binaural output, then implementation is simple, but spatialization quality and surround effect are degraded due to loss of decorrelation
Solution Approach 1:
The patent changes the parameter representation by introducing decorrelation factors (γ_front, γ_back) that modulate the combination of front and back transfer functions. Instead of simple mixing, the system uses frequency-dependent complex parameters that capture spatial characteristics, achieving improved spatialization quality while maintaining computational efficiency through parametric representation rather than full impulse response processing.
Data Source
AI summary
The invention is aimed at improving the quality of the filtering by transfer functions of HRTF type of signals (L, R) compressed in a transformed domain, for binaural playing on two channels (L-BIN, R-BIN), using a combination of HRTF filters (hL,L, hL,R) including a decorrelated version (HRTF-C*, HRTF-E*) of a few of these filters. For this purpose, a decorrelation cue is given with spatialization parameters (SPAT) accompanying the compressed signals (L, R). The Decorrelation comprises applying a different phase shift to each subband of the input signal combined with addition of an overall delay. The invention makes it possible to improve the broadening in the binaural rendition of audio scenes initially in a multi-channel format.