DTX Noise Synthesis Adaptation for Seamless Audio Transitions
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Solution Overview
Problem
Current methods for discontinuous transmission in scalable broadband speech codecs, such as ITU-T G.729.1 and 3GPP AMR-WB, fail to smoothly transition between narrow-band and broadband data rates during speech pauses, leading to disruptive changes in the synthesized noise signal, affecting the overall quality of the received audio.
Innovation Solution
The method involves determining the percentage of broadband active speech frames during active voice phases to adjust the noise information data rate accordingly, allowing for a quasi-continuous transition from narrow-band to broadband or vice versa during a DTX phase, using specific proportional factors to ensure a seamless signal quality adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If discontinuous transmission (DTX) is used to reduce data transmission rate during speech pauses, then data transmission efficiency is improved, but the transition between narrow-band and broadband data rates causes disruptive effects on the received audio signal
Solution Approach 1:
The patent applies dynamics by making the data rate adaptive rather than static. The system dynamically switches between narrow-band and broadband data rates based on the speech activity detection results and the determined percentage value, allowing the transmission system to adapt its characteristics to the current communication conditions while maintaining signal quality during transitions
Solution Approach 2:
The patent changes the data rate parameter based on the percentage of speech frames determined during the pause. By adjusting the data rate parameter according to the speech activity pattern detected before the pause, the system ensures smooth transitions between narrow-band and broadband modes, preventing disruptive effects on the received signal while maintaining transmission efficiency during pauses
2Reliability
If broadband data rate is used to improve audio quality, then audio impression is improved, but data transmission rate increases
Solution Approach 1:
The patent applies partial action by using broadband data rate only when necessary - specifically during speech pauses when the determined percentage indicates a need for higher quality noise synthesis. During active speech transmission, the system uses standard data rates, thus achieving improved audio quality where needed without continuously consuming excessive bandwidth
Data Source
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AI summary
A basic idea of the invention is to ascertain information on the course of the bit rate switching during an active speech phase. According to the invention, during the speech phase, information on the percentage proportion of broadband active speech frames in comparison to narrowband active speech frames is compiled on the part of the decoder. A high percentage proportion of broadband active speech frames indicates that a broadband use is preferred on the part of the codec and therefore a need exists for synthesizing noise information in broadband form during a DTX phase.