Digital Music Bit Extension Using Flat-Area Difference Correction
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Solution Overview
Problem
Existing bit extension processing methods fail to significantly improve sound quality when applied to digital music signals with sharply changing sample values.
Innovation Solution
A bit extension processing apparatus and method that includes framing, difference signal calculation, flat area detection and correction, difference signal averaging, and requantization error generation to enhance the quality of digital music signals by altering flat areas in the difference signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple bit extension processing method is employed that adds zero data to lower-order bits, then the processing is easy to implement, but the sound quality improvement is limited especially for musical pieces with sharply changing sample values
Solution Approach 1:
The patent segments the digital music signal into frames and further processes each frame by dividing it into groups of samples. This segmentation allows the system to apply different processing strategies to different portions of the signal, specifically identifying flat areas within groups and applying targeted corrections only where needed, rather than processing the entire signal uniformly.
Solution Approach 2:
The patent applies local quality by detecting flat areas (where consecutive samples have identical values) within specific groups of samples and applying correction processing only to those localized regions. The correction amount is determined based on the surrounding non-flat samples, ensuring that processing is applied precisely where needed without unnecessarily modifying other portions of the signal.
2Manufacturing precision
If bit extension processing is performed on a digital music signal of a calm musical piece having consecutive identical sample values, then the quality is improved, but it is not possible to improve the quality much for musical pieces having sharply changing sample values
Solution Approach 1:
The patent employs dynamic processing by continuously analyzing the input signal to detect flat areas and adapting the correction strategy in real-time. The system dynamically determines correction amounts based on the actual signal characteristics in each group, allowing it to effectively handle both calm musical pieces with many flat areas and pieces with sharply changing values where flat areas are rare or nonexistent.
Solution Approach 2:
The patent changes parameters by adjusting the correction amount based on the surrounding samples when correcting flat areas. The correction value is not fixed but is determined dynamically from the signal's local characteristics, allowing the system to adapt to different signal conditions and music types while maintaining processing effectiveness.
3Manufacturing precision
If flat area correction processing is applied to alter flat areas to not be flat according to surrounding patterns, then the correlation between requantization error signals and difference values is enhanced, but the processing complexity increases
Solution Approach 1:
The patent divides the signal processing into discrete frames and further segments each frame into groups of samples. This segmentation structure allows the complex correction processing to be applied in a systematic, modular manner, making the implementation more manageable and the complexity more controllable through structured organization.
Solution Approach 2:
The patent performs preliminary actions by detecting flat areas and determining correction amounts before actually applying the correction. The system calculates the correction values based on surrounding samples in advance, which streamlines the subsequent correction application and reduces the overall processing complexity by organizing operations in a logical sequence.
Data Source
AI summary
A framing processing unit converts a first digital music signal quantized with a first number of quantization bits, into frames. A difference signal calculation unit calculates a first difference signal in which a difference sample is a difference value between two adjacent samples. A flat area detection unit detects a flat area in the first difference signal. A flat area correction unit generate a second difference signal in which the flat area is altered to not be flat. A difference signal averaging unit calculates a difference average value and subtracts the difference average value from each sample value of the second difference signal to generate a third difference signal. A requantization error generation unit generates a requantization error signal. An addition unit adds the requantization error signal to the first digital music signal and outputs a second digital music signal having a second number of quantization bits.