High-Frequency Audio Encoding Using Low-Band Energy Prediction
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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, reducing the bit requirement by leveraging the energy relationship between low and high frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional encoding methods are used for high frequency signals, then accurate representation is achieved, but bit consumption increases significantly
Solution Approach 1:
The patent extracts only the essential energy information from high frequency signals rather than encoding the complete signal. By separating the energy characteristics (which need to be encoded) from the full signal data (which can be discarded), the method achieves accurate representation while dramatically reducing bit consumption.
Solution Approach 2:
The patent introduces low frequency signals as an intermediary to represent high frequency components. Instead of directly encoding high frequency signals, the system uses low frequency signals as a mediator that carries the essential energy information, enabling efficient compression while maintaining perceptual quality.
2Reliability
If high frequency signals are encoded with high precision, then signal fidelity is maintained, but compression efficiency deteriorates
Solution Approach 1:
The patent changes the encoding parameter from full signal representation to energy-only representation. By transforming the encoding target from time-domain signal values to frequency-domain energy characteristics, the method achieves both high signal fidelity (through energy preservation) and high compression efficiency (through parameter reduction).
3Quantity of substance
If spectral band replication is used to encode high frequency signals, then bit consumption is reduced, but utilization of low-high frequency relationship is insufficient
Solution Approach 1:
The patent makes low frequency signals multi-functional by using them both for their original purpose and as a basis for generating high frequency representations. The low frequency signals serve dual functions: maintaining their own integrity and simultaneously acting as templates for high frequency signal reconstruction through energy ratio application.
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.