Audio Decoder Background Noise Estimator for Bitrate Reduction
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Solution Overview
Problem
Current audio codecs do not effectively reduce transmission bitrate during inactive phases while maintaining noise generation quality, especially with the increasing demand for lower bitrate consumption in mobile devices and wireless transmission.
Innovation Solution
A parametric background noise estimate is continuously updated during active phases, allowing immediate noise generation in inactive phases without the need for a warm-up phase, by parameterizing the noise in the spectral domain and separating it from the useful signal, thus reducing bitrate and computational overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a warm-up phase with coded background noise representation is used after detecting inactive phase, then noise generation quality is improved, but transmission bitrate increases
Solution Approach 1:
The background noise parameters are continuously updated during active phases in advance, so that when inactive phase occurs, the decoder already has current noise parameters ready for immediate synthesis without requiring additional warm-up phase transmissions
Solution Approach 2:
Instead of transmitting actual coded background noise samples during warm-up phase, the patent uses parametric representation where only noise parameters are transmitted, creating a simplified copy that enables accurate noise regeneration with minimal bitrate
2Manufacturing precision
If conventional coded representation of background noise is transmitted during warm-up phase, then noise generation quality is improved, but device complexity increases
Solution Approach 1:
The patent transforms the noise representation from time-domain coded samples to frequency-domain parameters (spectral flatness, bandwidth, energy), enabling more efficient encoding and decoding while maintaining noise synthesis quality and reducing computational complexity
3Manufacturing precision
If parametric background noise estimate is continuously updated during active phase, then noise generation quality is improved, but computational complexity increases
Solution Approach 1:
By updating only a small set of noise parameters (spectral flatness, bandwidth, energy) rather than full noise spectra, the patent achieves continuous noise tracking with minimal computational overhead suitable for real-time processing
Solution Approach 2:
The patent updates noise parameters selectively based on detection of noise changes rather than continuously updating all parameters at full rate, reducing computational load while maintaining noise synthesis accuracy when needed
Data Source
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AI summary
An audio decoder comprises a background noise estimator that is configured to update a parametric background noise estimate during an active phase. It further comprises a background noise generator configured to synthesize an audio signal during an inactive phase.