Adaptive Parameter Grouping for Low-Bitrate Audio Side Information
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Solution Overview
Problem
Current multi-channel audio encoding techniques, such as BCC and parametric stereo, face challenges in achieving low bit rates for side information, which is essential for applications like streaming audio and video to mobile devices, as existing lossless encoding methods do not efficiently compress parameter values.
Innovation Solution
The proposed solution involves a compression unit that rearranges parameters into sequences of tuples, using a bit estimator to determine the most efficient encoding sequence, either in time or frequency, and applies a two-dimensional Huffman code to reduce bit rates further, with adaptive grouping and differential encoding to minimize side information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional lossless encoding methods are used for parametric side information, then the encoding is simple and fast, but the bit rate is too high for mobile applications
Solution Approach 1:
The patent segments the parametric side information into different groups based on their statistical properties and correlation characteristics. By dividing the parameters into distinct groups that can be encoded separately with different encoding strategies, the overall bit rate is reduced while managing encoding complexity through organized processing of smaller parameter sets rather than treating all parameters uniformly
Solution Approach 2:
The patent introduces a new dimension of organization by arranging parameters in a two-dimensional structure (frequency bins × time blocks) and applying encoding in both dimensions. This dimensional approach allows exploitation of correlations across frequency and time, achieving superior compression compared to conventional one-dimensional encoding while maintaining systematic complexity management
2Quantity of substance
If parameters are encoded independently without adaptive grouping, then the encoding process is simple, but compression efficiency is insufficient
Solution Approach 1:
The patent implements dynamic adaptive grouping where the grouping strategy is not fixed but adapts based on the actual statistical properties and correlation characteristics of the parametric data. The encoder dynamically determines optimal group configurations and encoding dimensions based on measured data properties, achieving higher compression efficiency while the adaptation logic maintains manageable complexity through systematic decision rules
Solution Approach 2:
The patent changes the encoding parameters (grouping size, dimensionality, encoding scheme) based on the statistical properties of the input data. By adjusting these parameters adaptively according to the actual data characteristics such as correlation strength and variance, the system achieves optimal compression for different types of parametric information while the parameter adjustment mechanism itself remains systematically controlled
3Quantity of substance
If multi-channel audio is transmitted with full channel information, then the audio quality is high, but the transmission bandwidth requirement is too large
Solution Approach 1:
The patent extracts and transmits only the essential parametric side information needed for accurate audio reconstruction at the decoder, rather than transmitting complete channel data. By identifying and transmitting only the critical parameters (such as inter-channel level differences, time differences, and correlation coefficients) that enable high-quality reproduction, the transmission data amount is dramatically reduced while maintaining audio quality through efficient parameter-based reconstruction
Solution Approach 2:
The patent uses parametric side information as an intermediary that enables the reconstruction of full multi-channel audio from a reduced set of transmitted data. These parameters act as mediators that carry the essential spatial and temporal relationship information between channels, allowing the decoder to synthesize the complete multi-channel signal with high fidelity using significantly less transmission bandwidth than direct channel transmission would require
Data Source
AI summary
The present invention is based on the finding that parameters including a first set of parameters of a representation of a first portion of an original signal and including a second set of parameters of a representation of a second portion of the original signal can be efficiently encoded, when the parameters are arranged in a first sequence of tuples and in a second sequence of tuples, wherein the first sequence of tuples comprises tuples of parameters having two parameters from a single portion of the original signal and wherein the second sequence of tuples comprises tuples of parameters having one parameter from the first portion and one parameter from the second portion of the original signal. An efficient encoding can be achieved using a bit estimator to estimate the number of necessary bits to encode the first and the second sequence of tuples, wherein only the sequence of tuples is encoded, that results in the lower number of bits.