Compressed Audio Restoration Using Brickwall Cutoff Detection
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Solution Overview
Problem
Compressed audio signals, processed by perceptual audio codecs, often lose significant audio components, leading to poorer perceived quality due to discarded high-frequency content, bandwidth limitations, and other compression artifacts.
Innovation Solution
The Signal Enhancer system analyzes compressed audio signals to identify lost components and generates corresponding treatments, such as bandwidth extension, harmonic fill, transient enhancement, and reverberation restoration, to restore the audio signal's quality by adding new signal components based on detected brickwall frequencies and other characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If perceptual audio codecs discard less audible components to reduce data size, then data compression ratio is improved, but audio signal quality deteriorates due to loss of high-frequency content and other audible components
Solution Approach 1:
The patent converts the harmful effect of discarded audio components into a benefit by using the detected brick wall frequency and signal characteristics to generate synthetic audio components. The system identifies what was lost during compression and creates replacement signals that restore the perceived audio quality, turning the compression artifact into an opportunity for targeted signal enhancement.
Solution Approach 2:
The patent changes the frequency domain parameters of the audio signal by detecting the brick wall frequency cutoff and generating new signal components above this frequency. The signal enhancer module modifies the spectral parameters by creating synthetic high-frequency content based on the detected compression characteristics, thereby restoring the frequency spectrum without requiring the original uncompressed data.
2Productivity
If perceptual audio codecs apply aggressive compression to achieve higher compression ratios, then data transfer efficiency is improved, but audible artifacts and quality loss increase
Solution Approach 1:
The patent transforms the harmful audible artifacts generated by aggressive compression into a diagnostic signal. The brick wall frequency detector identifies the compression-induced spectral cutoff, and this information is used to generate targeted enhancement signals that specifically address the artifacts created by the compression process, converting the harmful artifact into a guide for restoration.
Solution Approach 2:
The patent introduces an intermediary signal enhancement process between the compressed audio output and the final playback. The signal enhancer module acts as a mediator that processes the compressed signal, detecting its characteristics and applying appropriate restoration treatments to reduce audible artifacts before the audio reaches the listener.
3Manufacturing precision
If signal enhancement treatments are applied to restore lost audio components, then perceived audio quality is improved, but system complexity and processing requirements increase
Solution Approach 1:
The patent applies signal enhancement locally rather than uniformly across the entire audio spectrum. The brick wall frequency detector identifies specific frequency regions that require enhancement, and the signal enhancer module generates treatments targeted at those specific regions. This localized approach improves perceived quality where needed while avoiding unnecessary processing in regions that are already adequate.
Solution Approach 2:
The patent performs preliminary detection of brick wall frequency and signal characteristics before applying enhancement treatments. The detector module analyzes the compressed audio signal in advance to identify the compression artifacts and determine the appropriate enhancement strategy, allowing the system to prepare targeted restoration signals that are applied only when and where needed.
Data Source
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AI summary
A sampler module may divide an audio signal into a series of sequential samples. A signal quality detector module may identify a consistent brick wall frequency of the audio signal spanning a plurality of the sequential samples at an outset of the audio signal and determine a signal treatment indication proportional to the brick wall frequency. A signal enhancer module may sequentially receive and analyze one or more sample components of the audio signal to identify lost parts of the audio signal in the one or more sample components of respective sequential samples, and generate, in accordance with the signal quality indication, a corresponding signal treatment for each of the one or more sample components of respective sequential samples having a corresponding identified lost part.