Binaural Multi-Channel Decoding With HRTF Energy Compensation
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Solution Overview
Problem
Existing binaural decoding methods using predictive upmix techniques suffer from energy errors and spectral coloring due to non-energy-conserving upmixing rules, particularly when dealing with downmixed signals and spatial parameters, leading to artifacts in binaural audio reproduction.
Innovation Solution
A multi-channel decoder that calculates a gain factor to compensate for energy errors by considering both upmix rule information and head-related transfer function (HRTF) filters, allowing for efficient binaural rendering without fully rendering the multi-channel signal, thereby reducing or eliminating energy errors and spectral coloring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If non-energy-conserving upmixing rules are used to reconstruct multi-channel signals from downmixed signals, then waveform matching between reconstructed and original signals is improved, but energy errors are introduced
Solution Approach 1:
The patent changes the parameters of the upmixing process by introducing energy compensation factors that adjust the energy distribution in the reconstructed channels. The encoder calculates energy errors and transmits compensation parameters, while the decoder applies these parameters to correct the energy distribution, thereby maintaining both waveform matching accuracy and energy conservation.
2Productivity
If HRTF filters are combined based on prediction parameters for binaural rendering, then computational efficiency is improved, but spectral coloring artifacts occur
Solution Approach 1:
The patent converts the harmful spectral coloring effect into a beneficial outcome by using the prediction parameters not only for waveform matching but also for guiding the combination of HRTF filters. The energy compensation mechanism transforms the energy error that causes spectral coloring into a controlled parameter that improves binaural rendering accuracy when combined with HRTF filtering.
3Manufacturing precision
If full multi-channel signal rendering is performed before binaural filtering, then audio quality is improved, but computational complexity increases
Solution Approach 1:
The patent applies preliminary action by performing energy compensation and parameter optimization at the encoder stage before transmission. The encoder pre-calculates energy errors and determines compensation parameters, which are then transmitted to the decoder. This preliminary processing reduces the computational burden on the decoder while maintaining audio quality.
Solution Approach 2:
The patent extracts only the essential energy compensation parameters from the full multi-channel rendering process and transmits them separately. Instead of transmitting or processing complete multi-channel signals, the system extracts and transmits only the necessary control parameters that guide the binaural rendering process, significantly reducing computational complexity.
Data Source
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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 (180) 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 (182) for filtering the downmix signal so that an energy corrected binaural signal having a left binaural channel and a right binaural channel is obtained.