Audio Coding for Dense Transient Detection and Constant-SNR Quantization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional audio codecs face challenges in compressing audio signals with dense transient events like applause or rain without degrading perceived quality, often requiring increased computational complexity or loss of quality.
Innovation Solution
A method that determines the perceptual entropy of audio signals to selectively apply a constant signal-to-noise ratio (SNR) quantization mode, specifically for audio signals with dense transient events, using existing entropy calculations to avoid complexity and memory footprint increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional quantization modes are used for audio signals with dense transient events, then computational complexity remains low, but perceived audio quality degrades
Solution Approach 1:
The patent implements dynamic quantization mode selection that adapts to the transient density characteristics of audio signals. The encoder dynamically switches between conventional quantization modes and the specialized constant SNR quantization mode based on real-time analysis of perceptual entropy and transient detection, allowing optimal quality for each signal segment without permanently increasing system complexity
Solution Approach 2:
The patent changes the quantization parameter strategy by enforcing constant signal-to-noise ratio across frequency bands specifically for dense transient events, rather than using conventional variable SNR approaches. This parameter change improves quality for transient-rich signals while the selective application keeps overall computational complexity manageable
2Reliability
If constant SNR quantization mode is applied to all audio signals, then perceived quality improves for transient events, but other audio signal types experience degradation
Solution Approach 1:
The patent applies the constant SNR quantization mode locally only to audio segments identified as containing dense transient events, rather than uniformly to all audio signals. Through transient detection mechanisms analyzing perceptual entropy and signal characteristics, the system selectively applies the specialized quantization where needed while preserving conventional quantization for other signal types, maintaining both improved quality for transients and compatibility with diverse audio content
Solution Approach 2:
The system dynamically adjusts quantization mode based on the characteristics of each audio segment. Transient detection algorithms continuously monitor the input signal and trigger the constant SNR mode only when dense transient events are detected, allowing the system to adapt to different signal types and maintain versatility while improving quality where needed
3Reliability
If transient detection mechanisms are added to identify dense transient events, then appropriate quantization can be applied, but computational complexity and memory footprint increase
Solution Approach 1:
The patent makes the perceptual entropy calculation mechanism serve multiple functions: it continues to provide its traditional role in quality assessment while simultaneously serving as the basis for transient event detection. By reusing existing entropy values and frequency domain representations already computed during normal encoding, the system achieves transient detection capability without adding separate dedicated detection algorithms, thus avoiding significant increases in computational complexity and memory footprint
Solution Approach 2:
The existing perceptual entropy computation infrastructure serves the additional function of transient detection. The system leverages the already-computed entropy values and spectral information from the normal encoding pipeline to identify transient events, allowing the existing components to 'self-serve' the detection function without requiring external or additional complex mechanisms
Data Source
AI summary
The present disclosure relates to methods and apparatus for audio coding. A method of encoding a portion of an audio signal comprises determining whether the portion of the audio signal is likely to contain dense transient events, and if it is determined that the portion of the audio signal is likely to contain dense transient events, quantizing the portion of the audio signal using a quantization 5 mode that applies a substantially constant signal-to-noise ratio over frequency for the portion of the audio signal. The present disclosure further relates to a method of detecting dense transient events in a portion of an audio signal.