Audio Range Extension for Soft Sound Representation
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Solution Overview
Problem
Current audio signal coding techniques face limitations in extending the dynamic range of decoded parameter values, particularly in high-frequency reconstruction systems, where negative values are truncated, leading to errors and inability to represent soft sounds or silence effectively.
Innovation Solution
The proposed solution involves a decoding system that uses range extension techniques by identifying decoded values equal to the minimum of a codebook range and modifying them to produce extended values, allowing for negative parameter values and expanding the representable range from 0 to 35, enabling the representation of complete silence and soft sounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the codebook range is limited to non-negative values (0 to 35), then the coding protocol remains simple and compatible, but the dynamic range is insufficient and cannot represent soft sounds or silence effectively
Solution Approach 1:
The patent extends the parameter range by allowing negative values for the first frequency band while keeping the codebook structure unchanged. This is achieved by modifying the interpretation of decoded values: when a decoded value equals the minimum codebook value (0), it is mapped to an extended negative value (e.g., -12) rather than being truncated. This parameter extension resolves the contradiction by increasing dynamic range without fundamentally changing the coding protocol's simplicity or compatibility.
2Measurement precision
If negative parameter values are truncated to zero, then the coding protocol remains simple, but errors occur and soft sounds cannot be represented accurately
Solution Approach 1:
The patent applies preliminary action by pre-defining the mapping relationship between minimum codebook values and extended negative values before decoding occurs. The system prepares a lookup table or predefined rule set that maps codebook minimum values (0) to extended range values (e.g., -12, -24). During decoding, this pre-established mapping is applied automatically, eliminating the need for complex real-time calculations while accurately representing soft sounds and silence.
3Measurement precision
If the codebook range is extended to include negative values, then soft sounds and silence can be represented, but compatibility with existing coding protocols is compromised
Solution Approach 1:
The patent applies local quality by extending the parameter range only for the first frequency band while keeping other frequency bands unchanged. The extension is localized to specific conditions: when the decoded value equals the minimum codebook value (0) in the first band, it is mapped to an extended negative value. This localized approach maintains backward compatibility with existing coding protocols for other bands while improving soft sound representation where it is most needed.
Data Source
AI summary
Disclosed are some examples of systems, apparatus, methods and computer program products implementing techniques for extending the range of a set of decoded parameter values for a sequence of frequency bands in an identifiable time frame of an audio signal. In some implementations, the parameter values vary in relation to a sequence of time frames of the audio signal and in relation to a sequence of frequency bands in each time frame. In some implementations, it is determined that a decoded value corresponds to a minimum of a first range of values of a first coding protocol of a set of coding protocols. The determined value is modified to be below the minimum of the first range of values to produce an extended value. A modified set of decoded values including one or more extended values can thus be provided.