Hierarchical Audio Coding With Exponent-Based Bit Allocation
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Solution Overview
Problem
Current digital audio signal coding techniques, such as the G.711.1 coder, face challenges in achieving low complexity and memory efficiency while maintaining high quality, particularly in hierarchical coding and decoding processes, due to complex bit allocation and multiplexing procedures.
Innovation Solution
A method for hierarchical coding/decoding that allocates a predetermined number of enhancement bits to samples with greater exponent values, determining a threshold value to simplify bit allocation calculations and reduce memory and processing requirements, allowing for dynamic bit allocation without the need for an exponent map.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex bit allocation and multiplexing procedures are used in hierarchical coding/decoding, then the quality of digital audio signal is improved, but the device complexity and memory usage increase
Solution Approach 1:
The patent changes the parameter representation by introducing exponent and mantissa fields to describe sample amplitudes. This parameter transformation enables simplified bit allocation rules based on exponent values, reducing the complexity of traditional bit allocation procedures while maintaining audio signal quality through the hierarchical coding structure.
Solution Approach 2:
The patent segments the bit allocation process by allocating enhancement bits specifically to samples with greater exponent values. This segmentation allows the system to focus computational resources on samples that benefit most from enhancement, simplifying the overall allocation procedure while preserving audio quality through targeted bit distribution.
2Measurement precision
If traditional bit allocation methods are used in hierarchical coding, then the quality of digital audio signal is maintained, but the memory usage and processing demands increase
Solution Approach 1:
The patent employs lightweight, easily computable exponent values derived from sample amplitude representations. These exponent values serve as simple proxies for complex amplitude information, enabling efficient bit allocation decisions with minimal memory storage and processing requirements while maintaining the quality benefits of hierarchical coding.
Solution Approach 2:
By transforming sample amplitude information into exponent and mantissa components, the patent creates a parameter representation that is more amenable to efficient processing. The exponent field, in particular, provides a compact summary of amplitude magnitude that enables simplified bit allocation rules, reducing both memory usage and computational processing demands compared to traditional methods.
3Measurement precision
If dynamic bit allocation is implemented without simplification, then the quality of digital audio signal is improved, but the processing complexity increases
Solution Approach 1:
The patent implements dynamic bit allocation by allocating enhancement bits based on the exponent values of individual samples. This dynamic approach allows the system to adaptively allocate more bits to samples with higher amplitudes (greater exponents) while using fewer bits for lower amplitude samples, optimizing audio quality through variable bit allocation without requiring complex processing procedures.
Solution Approach 2:
The transformation of sample amplitudes into exponent-mantissa representation enables simplified dynamic bit allocation rules. The exponent field serves as a direct indicator of sample amplitude magnitude, allowing the system to dynamically allocate enhancement bits based on simple threshold comparisons of exponent values rather than complex amplitude analysis, thereby reducing processing complexity while maintaining dynamic adaptability.
Data Source
AI summary
A binary allocation in a hierarchical coding/decoding comprising a coding/decoding of a digital signal enhancement layer. The signal comprises a succession of L samples, each sample being represented by a mantissa and an exponent. The method comprises the allocation of a predetermined number Nb of enhancement bits to a part at least of the L samples of highest exponent values. In particular, the method comprises the steps: a) enumerating the exponents of the L samples each having a given value, b) calculating at least one aggregate of enumerations of exponents by decreasing values of exponent until the predetermined number Nb is approximated from above, for c) determining a threshold value of largest exponent iexp0 of sample for which no more enhancement bit is available, and allocating the Nb enhancement bits, according to chosen rules, to the samples whose exponent is greater than the aforesaid threshold value iexpo.