Audio Coding Multi-lag Format Autocorrelation Encoding
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Solution Overview
Problem
High-quality audio coding systems require large amounts of data for coding, resulting in low coding efficiency.
Innovation Solution
The method involves generating subband audio signals through spectral decomposition, determining a spectral envelope, and calculating autocorrelation information for each subband, which is then encoded along with the spectral envelope to create a high-efficiency encoded representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detailed waveform properties are used to describe audio signal, then audio quality is improved, but data amount increases resulting in low coding efficiency
Solution Approach 1:
The patent extracts only the essential features from the audio signal - specifically spectral envelope parameters and autocorrelation information - rather than encoding the complete waveform. This extraction approach maintains perceptual quality while dramatically reducing the data amount required for representation.
Solution Approach 2:
The audio signal is segmented into multiple subbands through spectral decomposition. By processing each subband separately and encoding only key parameters (spectral envelope and autocorrelation) for each, the system achieves efficient compression while preserving the perceptually important characteristics of the original signal.
2Quantity of substance
If statistical features are used instead of detailed waveform, then coding efficiency is improved, but audio quality deteriorates
Solution Approach 1:
The patent applies different encoding strategies to different parts of the spectrum. By computing autocorrelation information specifically for each subband and combining it with spectral envelope data, the system preserves local temporal and spectral characteristics that are crucial for perceptual quality, while still achieving efficient compression through parameter-based representation.
Data Source
AI summary
Described herein is a method of encoding an audio signal. The method comprises: generating a plurality of subband audio signals based on the audio signal; determining a spectral envelope of the audio signal; for each subband audio signal, determining autocorrelation information for the subband audio signal based on an autocorrelation function of the subband audio signal; and generating an encoded representation of the audio signal, the encoded representation comprising a representation of the spectral envelope of the audio signal and a representation of the autocorrelation information for the plurality of subband audio signals. Further described are methods of decoding the audio signal from the encoded representation, as well as corresponding encoders, decoders, computer programs, and computer-readable recording media.