Audio Signal DRC Processing at Attribute Change Boundaries
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Solution Overview
Problem
Conventional audio signal processing techniques often result in decoded signals with inappropriate amplitudes, leading to unnatural sound quality due to the direct output of large amplitude portions, which degrades subjective sound quality.
Innovation Solution
An audio signal processing apparatus that decodes bit streams on a frame-by-frame basis, using a detection unit to identify changes in attribute information between frames and processing the decoded signal by either using additional data from before or after the change, ensuring appropriate amplitude adjustment without extending across the change point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If additional data from adjacent frames is used to process the decoded signal, then smoothing is achieved and sudden volume changes are prevented, but subjective sound quality degrades when attribute information changes between frames
Solution Approach 1:
The patent applies different processing rules to different segments of the audio signal based on attribute information changes. When attribute information changes between frames, the patent selectively uses additional data only from frames before or after the change point, not across it. This local differentiation ensures that smoothing is applied where appropriate (within same attribute regions) while avoiding quality degradation at transition points between different attribute regions.
Solution Approach 2:
The patent dynamically changes the processing parameters (which additional data to use) based on the detected attribute information. By monitoring changes in attribute information between frames, the system adjusts its data selection strategy - using additional data from adjacent frames when attributes are consistent, and switching to use only pre-change or post-change data when attributes change. This parameter adaptation resolves the contradiction between smoothing and quality accuracy.
2Stress or pressure
If DRC data is applied to compress amplitude of decoded signal, then loud portions are suppressed, but unnatural sound occurs when attribute information mismatch causes inappropriate amplitude processing
Solution Approach 1:
The patent implements a feedback mechanism where the attribute information is continuously monitored and used to control the application of DRC data. The detection unit detects changes in attribute information, and this feedback determines whether additional data from adjacent frames should be used. When attribute information changes, the feedback loop prevents using mismatched DRC data, thereby avoiding unnatural sound while maintaining appropriate amplitude control when attributes are consistent.
Solution Approach 2:
The patent performs preliminary detection of attribute information changes before applying DRC processing. By detecting whether attribute information has changed between frames in advance, the system can pre-determine which additional data to use (or not use) for processing the current frame. This preliminary action prevents inappropriate DRC application that would cause unnatural sound, while still enabling effective amplitude compression when conditions are appropriate.
3Quantity of substance
If additional data from frames across attribute change points is used, then more data is available for processing, but the decoded signal with large amplitude is output incorrectly degrading sound quality
Solution Approach 1:
The patent applies local quality by differentiating between regions with consistent attribute information and regions with attribute changes. Within consistent regions, the patent utilizes additional data from adjacent frames to improve processing. At attribute change points, the patent creates a boundary where additional data from across the change is excluded. This local differentiation ensures sufficient data availability where safe while preventing quality degradation at critical transition points.
Solution Approach 2:
The patent segments the audio signal processing into distinct regions based on attribute information consistency. By identifying change points in attribute information, the patent divides the processing into segments where additional data usage is permitted (within segments) and where it is restricted (across segment boundaries). This segmentation strategy resolves the contradiction by allowing data utilization where it helps while preventing its harmful use where attributes change.
Data Source
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AI summary
An audio signal processing apparatus (100) that processes a bit stream generated by coding an audio signal on a frame-by-frame basis, the bit stream including, for each frame, coded data representing the audio signal, additional data and attribute information, the audio signal processing apparatus including a decoding unit (1 10) configured to decode the coded data to generate a decoded signal, a processing unit (140) configured to process the decoded signal, a detection unit (120) configured to detect whether or not there has been a change in the attribute information, and a storage unit (130), wherein the processing unit (140) is configured to, when the change is not detected, process the decoded signal by using at least two pieces of additional data stored, and when the change is detected, process the decoded signal by using only either additional data before detection of the change or additional data after detection of the change.