Spatial-Cue Reverb Processing for Multi-Channel Audio Downmix
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Solution Overview
Problem
Conventional methods for applying reverb to multi-channel audio signals do not effectively utilize spatial cue parameters to generate distinct reverb impulse responses for individual channels, resulting in a lack of personalized reverb application and suboptimal surround sound quality.
Innovation Solution
A method and system that generate discrete reverb channel signals in the QMF domain based on spatial cue parameters, allowing for individual application of reverb with different impulse responses to each channel, and subsequent downmixing to produce an N-channel reverbed output signal, utilizing pre-mix and post-mix matrices with time-varying coefficients to optimize reverb application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to apply reverb to multi-channel audio signals, then the processing is simple and fast, but the surround sound quality and spatial image perception are suboptimal
Solution Approach 1:
The patent divides the reverb processing into separate channels by extracting individual channels from the downmixed signal and applying distinct reverb impulse responses to each channel. This segmentation enables personalized reverb treatment for each spatial position, improving surround sound quality while maintaining manageable processing complexity through systematic channel separation.
Solution Approach 2:
The patent applies different reverb impulse responses to different audio channels based on their spatial characteristics. Each channel receives locally optimized reverb processing tailored to its specific spatial position, creating accurate spatial cues and enhancing the perceived spatial image without requiring uniform complex processing across all channels.
2Manufacturing precision
If spatial cue parameters are utilized to generate distinct reverb impulse responses for individual channels, then personalized reverb application and spatial image quality improve, but the processing complexity and computational requirements increase
Solution Approach 1:
The patent performs upmixing and extracts spatial cue parameters (CLD, CPC, ICC) before applying reverb processing. By preparing the individual channels and determining appropriate reverb impulse responses in advance, the system enables personalized reverb application that accurately reflects spatial relationships without adding excessive complexity during the actual reverb processing stage.
Solution Approach 2:
The patent utilizes spatial cue parameters (Channel Level Difference, Channel Prediction Coefficient, Inter-channel Cross Correlation) to determine appropriate reverb impulse responses for each channel. By changing processing parameters based on spatial characteristics, the system achieves accurate spatial image representation while maintaining efficient processing through parameter-driven impulse response selection.
Data Source
AI summary
A method and system for applying reverb to an M-channel downmixed audio input signal indicative of X individual audio channels, where X is greater than M. Typically, the method includes steps of: in response to spatial cue parameters indicative of spatial image of the downmixed input signal, generating Y discrete reverb channel signals, where each of the reverb channel signals at a time, t, is a linear combination of at least a subset of values of the individual audio channels at the time, t, and individually applying reverb to each of at least two of the reverb channel signals, thereby generating Y reverbed channel signals.