Dynamic Bit Allocation for Audio Coding Efficiency
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Solution Overview
Problem
Existing audio coding schemes face challenges in efficiently allocating bits to subbands of an audio signal, particularly in low-bit-rate applications, as they often require explicit side information transmission for bit allocation, which is inefficient and not directly used for coding, and do not account for variations in perceptual significance across subbands.
Innovation Solution
A dynamic bit allocation scheme based on coded gain parameters, where the encoder and decoder share knowledge of gain parameters, allowing bit allocation without explicit side information transmission, using gain-shape vector quantization and dynamic allocation techniques to adjust bit allocation among subbands based on their perceptual significance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If explicit side information is transmitted for bit allocation, then bit allocation accuracy is improved, but transmission overhead increases
Solution Approach 1:
The encoder and decoder both independently calculate bit allocation based on shared gain parameters and a standard algorithm, eliminating the need for the encoder to transmit explicit bit allocation side information. The system serves itself by using common knowledge at both ends to derive the same allocation decisions without communication overhead.
Solution Approach 2:
The patent extracts only the essential gain parameters that both encoder and decoder need to share, rather than transmitting complete bit allocation information. By taking out only the necessary parameters and deriving the rest locally, the system reduces side information overhead while maintaining allocation accuracy.
2Ease of manufacture
If uniform bit allocation is used across subbands, then implementation simplicity is improved, but coding efficiency deteriorates
Solution Approach 1:
The patent applies local quality by allocating bits dynamically to different subbands based on their individual perceptual significance, rather than using uniform allocation. Each subband receives a customized bit allocation proportional to its importance, improving coding efficiency while maintaining implementation simplicity through a systematic algorithm.
Solution Approach 2:
The bit allocation scheme transitions from static uniform allocation to dynamic allocation that adapts to the perceptual characteristics of each subband. The system dynamically adjusts bit distribution based on gain parameters and perceptual models, allowing coding efficiency to vary with signal content while preserving implementation simplicity through standardized procedures.
3Manufacturing precision
If more bits are allocated to each subband, then coding quality is improved, but bit rate consumption increases
Solution Approach 1:
The patent changes the allocation parameter from fixed uniform bits-per-subband to dynamic bits-per-subband based on perceptual significance. By changing how bits are distributed rather than increasing total bits, the system improves coding quality for perceptually important subbands while maintaining bit rate efficiency through selective allocation.
Solution Approach 2:
Instead of uniformly increasing bits across all subbands, the system applies local quality enhancement by allocating additional bits only to subbands with high perceptual significance. This targeted approach improves coding quality where it matters most while avoiding unnecessary bit rate consumption in less important frequency regions.
Data Source
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AI summary
A dynamic bit allocation operation determines a bit allocation for each of a plurality of vectors, based on a corresponding plurality of gain factors, and compares each allocation to a threshold value that is based on a dimensionality of the vector. There is described a method of bit allocation, said method comprising: for each among a plurality of vectors, calculating a corresponding one of a plurality of gain factors; for each among the plurality of vectors, calculating a corresponding bit allocation that is based on the gain factor; for at least one among the plurality of vectors, determining that the corresponding bit allocation is not greater than a minimum allocation value; and, in response to said determining, for each of said at least one vector, changing the corresponding bit allocation.