Audio Bit Allocation via Frequency Band Grouping
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Solution Overview
Problem
Current audio coding technologies face inefficiencies in bit allocation, leading to random and scattered allocation, especially at low and medium bit rates, resulting in discontinuous quantization in the time domain.
Innovation Solution
A method and apparatus for bit allocation that groups frequency bands by energy characteristics, performing initial and secondary inter-group bit allocation using saturation or weighting algorithms to stabilize bit distribution across frames and reduce discontinuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If iterative bit allocation is performed in full frequency band using fixed iteration parameters, then bit allocation is performed according to normalized energy of each sub-band, but the allocation becomes random and scattered at low and medium bit rates, causing discontinuous quantization in time domain
Solution Approach 1:
The frequency band is divided into multiple groups (first group, second group, etc.) based on normalized energy values of sub-bands. This segmentation allows different bit allocation strategies for different frequency regions, preventing random scattering and ensuring stable allocation across frames while maintaining continuity in time domain quantization.
2Ease of manufacture
If integral bit allocation is used with bandwidth value as smallest unit, then bit allocation is simplified, but allocation efficiency decreases at low bit rates where many bands receive no bits and others receive too many bits
Solution Approach 1:
The patent introduces dynamic bit allocation within each group based on the specific characteristics and energy values of sub-bands. Instead of using fixed integral bandwidth values, the system dynamically determines optimal bit distribution within groups, improving allocation efficiency at low bit rates while maintaining implementation simplicity through the grouped structure.
3Device complexity
If uniform iteration parameters are used for all sub-bands, then the bit allocation process is simplified, but allocation results become random and scattered because parameters do not adapt to different sub-band characteristics
Solution Approach 1:
The patent applies different bit allocation strategies to different groups of sub-bands based on their local characteristics. Each group receives tailored allocation parameters according to its normalized energy values, improving allocation accuracy while keeping the overall process manageable through the grouped structure rather than requiring completely different parameters for each individual sub-band.
Data Source
AI summary
A method and an apparatus for allocating bits of an audio signal. The method includes dividing a frequency band of an audio signal into multiple sub-bands, and quantizing a sub-band normalization factor of each sub-band; classifying the multiple sub-bands into multiple groups, and acquiring a sum of intra-group sub-band normalization factors of each group; performing initial inter-group bit allocation to determine the initial number of bits of each group; performing secondary inter-group bit allocation to allocate coding bits of the audio signal to at least one group; and allocating the bits of the audio signal to sub-bands in the group. The present disclosure can, by means of grouping, ensure relatively stable allocation in a previous frame and a next frame and reduce an impact of global allocation on local discontinuity in a case of low and medium bit rates.