Compressed Audio Signal Enhancement for Restoring Lost Harmonics
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Solution Overview
Problem
Compressed audio signals suffer from undesirable audible differences due to data compression, which discards perceptually less important components, leading to reduced quality, especially at lower bitrates.
Innovation Solution
The Signal Enhancer system modifies compressed audio signals by restoring or enhancing discarded components such as bandwidth, harmonics, transients, reverb, and masked signals, and phase-aligning harmonics, operating on individual spatial slices or Mid-Side components of stereo signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data compression is applied to reduce audio signal size, then storage and transmission efficiency is improved, but audible quality deteriorates due to discarded signal components
Solution Approach 1:
The patent applies discarding and recovering by first identifying and discarding inaudible signal components during compression, then recovering and reconstructing the discarded audible components through analysis of remaining signal characteristics and synthesis of missing harmonics, transients, and spatial information
Solution Approach 2:
The patent uses an intermediary approach by introducing a signal enhancer system that acts as a mediator between the compressed audio signal and the final output, analyzing the compressed signal and generating enhanced versions with recovered components through intermediate processing stages including spectral analysis and synthesis
2Quantity of substance
If aggressive compression is used to achieve lower bitrates, then data usage is reduced, but perceived audio quality deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the bitrate parameter to enable aggressive compression, then compensating for the resulting quality loss by changing other parameters including spectral distribution, harmonic content, transient characteristics, and spatial parameters to restore perceived audio fidelity
Solution Approach 2:
The patent uses partial action by applying enhancement only to specific signal components that were discarded during compression, such as certain frequency ranges, transient portions, or spatial elements, rather than uniformly processing the entire signal, thereby efficiently restoring quality at lower bitrates
3Volume of stationary object
If signal components are discarded during compression, then file size is reduced, but restoration of missing components becomes more difficult
Solution Approach 1:
The patent applies preliminary action by performing analysis and identification of discardable signal components before the actual compression process, and preliminarily establishing the framework for restoration by analyzing remaining signal characteristics that can inform the reconstruction of missing components
Solution Approach 2:
The patent uses segmentation by dividing the audio signal into distinct components including harmonics, transients, reverb, and spatial elements, allowing selective discarding of inaudible portions while preserving and independently restoring audible components through separate processing channels
Data Source
AI summary
A system for processing compressed audio includes a signal enhancer module configured to generate one or more signal treatments. The one or more signal treatments may be generated by the signal enhancer module based on analysis of the incoming audio signal. Alternatively, or in addition, characteristics of the incoming audio signal may be provided to the signal enhancer module for use in generating the one or more signal treatments. The one or more signal treatments may be added to file audio signals.