High-Frequency Signal Coding with Low-Band Energy Ratio Reconstruction
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Solution Overview
Problem
Existing audio signal encoding and decoding technologies are inefficient in handling high frequency signals, as they require significant bits for accurate representation, which is not necessary for human perception, and do not effectively utilize the relationship between low and high frequency signals.
Innovation Solution
The method involves linear prediction of high frequency signals to extract coefficients, generating signals using these coefficients and low frequency signals, and calculating energy ratios to encode and decode high frequency signals efficiently, thereby reducing the bit requirement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional encoding methods are used for high frequency signals, then encoding accuracy is maintained, but bit consumption increases significantly
Solution Approach 1:
The patent extracts only the essential characteristics of high frequency signals (energy values and spectral shape information) rather than encoding the complete signal. By separating the high frequency signal representation into extracted features, the system achieves accurate reconstruction with significantly reduced bit consumption.
Solution Approach 2:
The patent applies partial action by encoding only the most important aspects of high frequency signals - specifically the energy values and spectral envelope - while omitting less critical details. This partial encoding approach maintains perceptual quality while reducing bit rate requirements.
2Manufacturing precision
If high frequency signals are encoded with high precision, then signal quality is improved, but encoding efficiency deteriorates
Solution Approach 1:
The patent changes the representation parameters of high frequency signals from time-domain samples to frequency-domain features (energy values, spectral shape). This parameter transformation enables more efficient encoding by capturing essential signal characteristics in a compressed form that maintains quality while improving encoding efficiency.
Solution Approach 2:
The patent segments the audio signal into low frequency and high frequency components, applying different encoding strategies to each. The high frequency portion is further segmented into extractable features (energy, spectral shape), allowing efficient processing and improved encoding efficiency without sacrificing signal quality.
3Quantity of substance
If spectral band replication is used to decode high frequency signals, then bit requirement is reduced, but utilization of low-high frequency relationship is insufficient
Solution Approach 1:
The patent employs feedback by using the decoded low frequency signal to inform and guide the high frequency signal reconstruction process. The spectral shape and energy characteristics extracted from the high frequency signal are used to adaptively shape the synthesized high frequency components, creating a feedback loop that improves the utilization of the low-high frequency relationship.
Solution Approach 2:
The patent creates a composite representation by combining low frequency signal components with extracted high frequency characteristics (energy values, spectral shape). This composite approach synthesizes high frequency signals that incorporate information from both low and high frequency domains, enhancing the utilization of their relationship while reducing bit requirements.
Data Source
AI summary
Provided are a method and apparatus for encoding and decoding a high frequency signal by using a low frequency signal. The high frequency signal can be encoded by extracting a coefficient by linear predicting a high frequency signal, and encoding the coefficient, generating a signal by using the extracted coefficient and a low frequency signal, and encoding the high frequency signal by calculating a ratio between the high frequency signal and an energy value of the generated signal. Also, the high frequency signal can be decoded by decoding a coefficient, which is extracted by linear predicting a high frequency signal, and a low frequency signal, and generating a signal by using the decoded coefficient and the decoded low frequency signal, and adjusting the generated signal by decoding a ratio between the generated signal and an energy value of the high frequency signal.