Adaptive Quantization Tables for Multi-Channel Audio Encoding
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Solution Overview
Problem
Conventional multi-channel audio encoding techniques require high bitrate due to fixed quantization methods, which are inefficient in encoding and decoding spatial parameters, limiting their applicability to arbitrarily expanded channel environments.
Innovation Solution
The method involves determining and quantizing channel level differences (CLDs) between pairs of channels, considering their location properties, and using adaptive quantization tables to optimize bit allocation, allowing for efficient encoding and decoding of multi-channel audio signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed quantization with a single quantization table is used, then the encoding process is simple, but the bitrate increases and encoding efficiency deteriorates
Solution Approach 1:
The patent divides the single quantization table into multiple quantization tables (first quantization table and second quantization table) with different quantization step sizes. The second quantization table uses smaller step sizes for better precision, while the first uses larger step sizes for coarser quantization. This segmentation allows selective application based on spatial parameters, resolving the contradiction between simplicity and bitrate efficiency.
Solution Approach 2:
The patent introduces dynamic selection of quantization tables based on spatial parameters (inter-channel correlation and channel level difference). Instead of using a fixed quantization table, the system dynamically chooses between the first and second quantization tables according to the characteristics of each channel pair, optimizing bitrate efficiency while maintaining encoding flexibility.
2Device complexity
If fixed quantization with a single quantization table is used, then the decoding process is simple, but encoding/decoding efficiency deteriorates
Solution Approach 1:
The patent segments the quantization process into multiple tables that are selectively applied. The decoding apparatus receives information about which quantization table was used and applies the corresponding inverse quantization, maintaining simplicity while improving overall efficiency through the segmented approach.
Solution Approach 2:
The patent incorporates feedback mechanisms where the encoding apparatus determines which quantization table to use based on spatial parameters and transmits this information to the decoding apparatus. The decoding apparatus uses this feedback to select the appropriate inverse quantization table, ensuring synchronized and efficient decoding without increasing complexity.
3Ease of manufacture
If conventional quantization methods are used, then implementation is straightforward, but applicability to arbitrarily expanded channel environments is limited
Solution Approach 1:
The patent creates a universal quantization framework that can handle any number of channels by defining multiple quantization tables and selecting them based on spatial parameters. The system processes channel pairs generically, making it adaptable to stereo, 5.1, 7.1, or any expanded channel configuration while maintaining straightforward implementation through consistent selection logic.
Solution Approach 2:
The patent changes the quantization parameter (step size) based on spatial characteristics of channel pairs. By adjusting which quantization table is applied according to inter-channel correlation and level difference, the system adapts to different channel configurations and spatial arrangements, enhancing versatility while keeping the implementation framework consistent and straightforward.
Data Source
AI summary
Methods of encoding and decoding a multi-channel audio signal and apparatuses for encoding and decoding a multi-channel audio signal are provided. The method of decoding a multi-channel audio signal includes an unpacking unit which extracts a quantized CLD between a pair of channels of a plurality of channels from a bitstream, and an inverse quantization unit which inverse-quantizes the quantized CLD using a quantization table that considers the location properties of the pair of channels. The methods of encoding and decoding a multi-channel audio signal and the apparatuses for encoding and decoding a multi-channel audio signal can enable an efficient encoding/decoding by reducing the number of quantization bits required.