Spectrum-Compensated Audio Compression for Playback Distortion
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Solution Overview
Problem
Existing audio compression methods using dynamic range compressors (DRC) fail to effectively adjust the dynamic range of audio signals with varying amplitudes, leading to distortion and reduced audibility due to inconsistent acoustic output thresholds across different frequency bands.
Innovation Solution
Implementing a spectrum compensation filter before the DRC to adjust the amplitude of distorted frequency bands, followed by calculating a compression coefficient to expand the compression range without significantly reducing the gain of loud sound frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compression range is expanded and the amplitude of the audio signal is reduced, then the peak values are controlled within the acoustic output threshold, but low-frequency gain is reduced and distortion may occur
Solution Approach 1:
The patent applies different compression strategies to different frequency bands. The DRC processes each frequency band independently with customized compression coefficients, allowing precise control over peak values in each band while preserving low-frequency gain characteristics. This localized approach prevents uniform compression from causing distortion in specific frequency ranges.
Solution Approach 2:
The system dynamically adjusts compression coefficients based on the input audio signal's frequency spectrum and amplitude characteristics. By changing the compression parameters adaptively rather than using fixed values, the system can control peak values effectively while avoiding distortion caused by inappropriate compression settings for specific signal types.
2Reliability
If the amplitude of audio signals with large amplitudes is compressed, then peak values are within the acoustic output threshold, but the audibility is affected
Solution Approach 1:
The patent applies frequency-band-specific compression coefficients that preserve audibility in critical frequency ranges while controlling peak values. Each frequency band receives tailored compression treatment, ensuring that important audio information is maintained even when overall amplitude is reduced to comply with acoustic output thresholds.
Solution Approach 2:
The system continuously monitors the compressed audio signal and adjusts compression coefficients in real-time based on the output characteristics. This feedback mechanism ensures that compression is applied only when necessary to meet acoustic output thresholds, preserving audibility by avoiding excessive compression that would degrade audio quality.
3Device complexity
If a fixed compression coefficient is used for all audio signals, then the device complexity is reduced, but the audio signal quality deteriorates due to inability to adapt to different amplitudes
Solution Approach 1:
The patent implements dynamic compression coefficients that adapt to the amplitude and frequency characteristics of different audio signals. Rather than using fixed values, the system calculates and applies customized compression parameters for each signal, improving audio quality while maintaining reasonable computational complexity through efficient signal processing algorithms.
Data Source
AI summary
An audio compression method, includes: obtaining a first audio signal to be processed; performing, by using a spectrum compensation filter, filtering processing on the first audio signal based on a preset target spectrum to obtain a second audio signal, where the target spectrum is correlated with a distorted frequency band of the audio playing device; using a preset dynamic range compressor (DRC) to process the second audio signal to obtain a compression coefficient; and outputting a compressed signal according to the compression coefficient. The method may expand a compression range, reduce an occurrence rate of distortion when playing the audio signal and improve a playing quality of the audio signal, without significantly reducing the gain of the loud sound frequency band.