Signal Decoding with Selective Noise Filling for Sparse Sub-Bands
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Solution Overview
Problem
In frequency domain codec algorithms, low bit rates result in insufficient bits for spectral coefficients, leading to poor decoding quality, particularly for less important spectral coefficients which are not encoded, causing issues like 'empty feeling' or 'sound of water' in audio signals.
Innovation Solution
A method and device for decoding signals that classify sub-bands into saturated and unsaturated bit allocation categories, performing noise filling on spectral coefficients with insufficient bits to reconstruct missing values based on harmonic parameters, improving decoding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noise filling is performed on all sub-bands, then signal decoding quality is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent applies noise filling selectively only to sub-bands with unsaturated bit allocation, rather than uniformly to all sub-bands. This localized approach concentrates computational resources on areas where they are most needed (sub-bands with missing spectral coefficients) while avoiding unnecessary processing in sub-bands that already have complete information, thereby improving decoding quality where necessary without proportionally increasing overall computational complexity
2Measurement precision
If more bits are allocated to each sub-band, then spectral resolution is improved, but bitstream length and transmission bandwidth increase
Solution Approach 1:
The patent changes the bit allocation parameter dynamically based on sub-band characteristics. Instead of allocating bits uniformly or in fixed amounts, the system identifies sub-bands with unsaturated bit allocation (where spectral coefficients are missing or incomplete) and allocates additional bits specifically to those sub-bands. This parameter adaptation allows the system to achieve necessary spectral resolution only where needed, optimizing the trade-off between resolution and bitstream length
3Reliability
If noise filling is performed on sub-bands with saturated bit allocation, then decoding completeness is improved, but processing overhead increases
Solution Approach 1:
The patent extracts and identifies sub-bands with unsaturated bit allocation from the overall frequency spectrum, separating them from sub-bands with saturated bit allocation. By taking out only the sub-bands that require noise filling (those with unsaturated allocation), the system avoids unnecessary processing of sub-bands that already have complete spectral information, thereby improving decoding completeness for problematic areas without incurring processing overhead for already-complete areas
Data Source
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AI summary
Embodiments of the present invention provide a method and device for decoding a signal. The method for decoding a signal includes: obtaining spectral coefficients of sub-bands from a received bitstream by means of decoding; classifying sub-bands in which the spectral coefficients are located into a sub-band with saturated bit allocation and a sub-band with unsaturated bit allocation; performing noise filling on a spectral coefficient that has not been obtained by means of decoding and is in the sub-band with unsaturated bit allocation, so as to reconstruct the spectral coefficient that has not been obtained by means of decoding; and obtaining a frequency domain signal according to the spectral coefficients obtained by means of decoding and the reconstructed spectral coefficient. In the foregoing embodiments of the present invention, a sub-band with unsaturated bit allocation in a frequency domain signal may be obtained by classification, and a spectral coefficient that has not been obtained by means of decoding and is in the sub-band with unsaturated bit allocation may be reconstructed, thereby improving signal decoding quality.