Multi-Channel Audio Encoding Residual Signal Extraction
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Solution Overview
Problem
Conventional audio encoding systems that reduce the number of channels by discarding residual signals result in significant data reduction but also lead to undesirable perceptual distortion, and decoding devices struggle to accurately reconstruct original signals due to the absence of residual information.
Innovation Solution
An encoding device and method that output residual signals instead of discarding them, allowing for improved signal quality by selecting and attenuating perceptually relevant time and frequency segments, and a decoding device that receives and combines residual signals with synthetic ones to enhance decoded audio quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If residual signals are discarded to reduce data amount, then data reduction is achieved, but perceptual distortion increases
Solution Approach 1:
The patent extracts only the essential components from the residual signals for transmission. Instead of transmitting complete residual signals or discarding them entirely, the system extracts key parameters and components that are most important for perceptual quality, thereby reducing data amount while minimizing information loss.
Solution Approach 2:
The patent applies different processing strategies to different parts of the audio signal based on their perceptual importance. Critical frequency regions and time segments receive higher priority in residual signal transmission, while less critical parts use more aggressive compression, achieving local optimization of quality versus data rate.
2Quantity of substance
If residual signals are discarded to achieve data reduction, then transmission capacity requirements decrease, but signal reconstruction accuracy deteriorates
Solution Approach 1:
The patent introduces an intermediary representation of the residual signals that bridges the gap between complete residual signals and no residual signals. This intermediary form contains compressed or parameterized residual information that enables accurate signal reconstruction while requiring less transmission capacity than full residual signals.
Solution Approach 2:
The patent transforms the residual signals from their original time-domain or frequency-domain representation into a parameterized form. By changing the representation parameters (e.g., using spectral parameters, perceptual parameters, or compressed domain representations), the system achieves efficient transmission with adequate reconstruction accuracy.
3Loss of information
If complete residual signals are transmitted to maintain signal quality, then perceptual distortion decreases, but data amount increases
Solution Approach 1:
The patent segments the residual signals into distinct components or frequency regions that can be processed and transmitted separately. This segmentation allows the system to prioritize transmission of the most perceptually relevant segments while using more efficient compression or approximation for less critical segments, reducing overall data amount while maintaining quality.
Solution Approach 2:
The patent transmits a partial representation of the residual signals that contains sufficient information for perceptually adequate reconstruction. Rather than transmitting complete residual signals, the system transmits enough information to achieve the required quality level, using partial action to balance quality and data rate.
Data Source
AI summary
An encoding device (1) for converting a first number (M) of input audio channels into a second, smaller number (N) of output audio channels comprises at least one conversion unit (12) for converting a first signal (Lf; Rf; Co) and a second signal (Lr; Rr; Le) into a third signal (L; R; C) and a fourth signal (Ls; Rs; Cs). The third, dominant signal contains most of the signal energy of the first and second signals, while the fourth, residual signal contains the remainder of said signal energy. The encoding device is arranged for using the third signal (L; R; C) to produce an output signal and for outputting the fourth signal (Ls; Rs; Cs). A decoding device (2) for converting a first number (N) of input audio channels into a second, larger number (M) or output audio channels comprises at least one conversion unit (24) for converting a first signal (L; R; C) and a second signal (Ld; Rd; Ld) into a third signal (Lf, Rf; Co) and a fourth signal (Lr; Rr; Le). The first, dominant signal contains most of the signal energy of the third and fourth signal, while the second, residual signal contains the remainder of said signal energy. The encoding device is arranged for receiving at least one-second signal (Ld; Rd; Cd).