Binaural Multi-Channel Decoding for Non-Energy-Conserving Upmix
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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, particularly 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
1Productivity
If non-energy-conserving upmixing rules are used for binaural decoding, then computational efficiency is improved, but energy errors and spectral coloring artifacts occur
Solution Approach 1:
The patent extracts and corrects only the energy error component from the upmixing process rather than fully rendering all intermediate channels. By calculating a gain factor that compensates for energy loss and applying it directly to the downmixed signal, the system achieves computational efficiency while eliminating energy errors and spectral coloring artifacts.
2Measurement precision
If prediction parameters are used for waveform matching, then time domain accuracy is improved, but energy conservation deteriorates
Solution Approach 1:
The patent changes the parameter representation by using gain factors derived from prediction parameters to correct energy errors. Instead of directly using prediction parameters for upmixing (which causes energy loss), the system calculates compensation gain factors and applies them to the downmixed signal, thereby maintaining waveform matching accuracy while restoring energy conservation.
3Device complexity
If HRTF filters are combined based on prediction parameters, then binaural rendering is simplified, but spectral coloring artifacts increase
Solution Approach 1:
The patent converts the harmful effect of energy loss in prediction-based upmixing into a beneficial correction mechanism. By calculating gain factors that compensate for the energy error introduced by using prediction parameters, the system transforms what would be a source of spectral coloring artifacts into a means of achieving accurate binaural rendering with simplified filter combination.
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.