Binaural Multi-Channel Decoder for Upmix Energy Error 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 correct 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, thereby reducing 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 converts the harmful energy error introduced by non-energy-conserving upmixing rules into a correctable parameter. By explicitly calculating the energy error based on the upmixing rule and applying compensatory gain factors, the system transforms the previously harmful energy loss into a controlled and corrected aspect of the decoding process, eliminating spectral coloring artifacts while maintaining computational efficiency.
2Speed
If non-energy-conserving upmixing rules are used for binaural decoding, then processing speed is improved, but spectral coloring artifacts increase
Solution Approach 1:
The patent transforms the harmful spectral coloring artifact into a correctable issue by introducing gain factor calculation based on energy error compensation. The system maintains the fast processing of non-energy-conserving upmixing rules while adding a correction step that eliminates spectral coloring, thus converting the previously harmful artifact into a controlled parameter.
Solution Approach 2:
The patent introduces an intermediary gain factor calculation step between the upmixing process and the final binaural output. This intermediary component computes the energy error and applies appropriate gain compensation, serving as a mediator that connects the fast but inaccurate upmixing process with the required audio quality output, thereby eliminating spectral coloring artifacts without sacrificing processing speed.
3Manufacturing precision
If energy correction is applied using gain factors, then audio quality is improved, but computational complexity increases
Solution Approach 1:
The patent applies partial correction by focusing the gain factor calculation only on the specific energy error introduced by the upmixing rule, rather than performing a complete re-optimization of the entire decoding process. This selective approach achieves sufficient audio quality improvement without the excessive computational complexity of a full optimization, applying just enough correction to eliminate spectral coloring artifacts.
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.