Binaural Multi-Channel Decoding With HRTF-Based Energy Correction
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Solution Overview
Problem
Existing methods for binaural decoding of multi-channel audio signals using HRTF filtering face challenges in energy conservation and spectral coloring due to non-energy-conserving upmixing rules, especially when downmixing signals with spatial parameters lead to energy errors and artifacts.
Innovation Solution
A multi-channel decoder is developed that calculates a gain factor to reduce or eliminate energy errors by using upmix rule information and HRTF filter characteristics, allowing for energy-corrected binaural signal generation without fully rendering the multi-channel signal, and applies this gain factor during filtering to mitigate spectral coloring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If non-energy-conserving upmixing rules are used to achieve waveform matching, then time domain waveform matching quality is improved, but energy conservation deteriorates causing energy errors
Solution Approach 1:
The patent changes the parameters of the upmixing process by introducing energy correction factors that adjust the energy distribution of upmixed channels. The system modifies the upmixing parameters dynamically to compensate for energy loss while preserving waveform matching quality, thereby resolving the contradiction between waveform accuracy and energy conservation.
2Productivity
If HRTF filters are combined based on prediction parameters, then binaural decoding efficiency is improved, but spectral coloring artifacts increase due to energy errors
Solution Approach 1:
The patent introduces an intermediary energy correction stage between the prediction parameter-based upmixing and the HRTF filtering process. This intermediary component corrects energy errors before they propagate to the binaural output, thereby eliminating spectral coloring artifacts while preserving the efficiency benefits of prediction-based filtering.
3Loss of information
If prediction parameters are used for upmixing, then data rate efficiency is improved, but energy distribution accuracy deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where energy distribution information from the upmixed channels is fed back to adjust the prediction parameters. This feedback loop allows the system to maintain data rate efficiency while continuously correcting energy distribution accuracy, resolving the contradiction between compact parameter representation and precise energy control.
Data Source
AI summary
A multi-channel decoder for generating a binaural signal from a downmix signal using upmix rule information on an energy-error introducing upmix rule for calculating a gain factor based on the upmix rule information and characteristics of head related transfer function based filters corresponding to upmix channels. The one or more gain factors are used by a filter processor for filtering the downmix signal so that an energy corrected binaural signal having a left binaural channel and a right binaural channel is obtained.