Pitch Period Estimation for VoIP Packet Loss Concealment
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Solution Overview
Problem
Existing methods for packet loss concealment in voice over Internet Protocol (VoIP) systems suffer from inaccurate estimation of pitch period, leading to errors in compensating lost voice frames, resulting in discontinuous phase and amplitude, especially during gradual voice changes.
Innovation Solution
A method and device that estimate the pitch period by selecting candidate periods with frequencies lower than or equal to the lowest possible pitch period, and tune the pitch period by sliding windows to improve matching values, enhancing correlation between recovered and subsequent data frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If autocorrelation analysis method is used to estimate pitch period, then the pitch period can be obtained for pitch waveform substitution, but the estimation accuracy is poor leading to frequency multiplication errors and phase discontinuity
Solution Approach 1:
The patent applies dynamics by making the pitch period estimation adaptive rather than static. It uses autocorrelation analysis dynamically adjusted with pitch period tuning and frequency multiplication elimination, allowing the system to adapt to varying voice characteristics and maintain accuracy across different speech conditions, thereby improving both measurement precision and phase continuity reliability
Solution Approach 2:
The patent changes parameters by introducing pitch period tuning mechanisms that adjust the estimated pitch period based on correlation values and frequency constraints. It modifies the autocorrelation function parameters and applies frequency multiplication elimination to correct estimation errors, directly improving pitch period estimation accuracy and preventing phase discontinuity
2Device complexity
If only history data before lost frame is used for compensation, then the processing is simple, but the correlation with subsequent data frames is weak causing amplitude discontinuity during gradual voice changes
Solution Approach 1:
The patent applies preliminary action by preparing multiple candidate pitch periods and tuning the pitch period estimation before actual packet loss compensation occurs. It pre-calculates correlation values and adjusts pitch period parameters in advance, so when loss compensation is needed, the system can quickly apply accurate parameters without complex real-time processing, maintaining both simplicity and amplitude continuity
Solution Approach 2:
The patent implements feedback by using correlation analysis between compensated frames and subsequent received frames to validate and adjust pitch period estimates. It continuously monitors the quality of compensation and refines pitch period parameters based on observed performance, improving amplitude continuity while managing processing complexity through iterative optimization
Data Source
AI summary
A method, device and system to implement hiding the loss packet are provided. The provided method, device and system recover the lost frame according to the data before and after the lost frame and enhances the correlation of the recovered lost frame data and the data after the lost frame. A method and device for estimating pitch period are also provided which select a pitch period from the initial pitch period and the pitch periods corresponding to the frequencies which are one or more times higher than the frequencies corresponding to the initial pitch period as the final estimated pitch period, may improve frequency multiplication when estimating the pitch period; in addition, by tuning of the pitch period by matching the waves, the error of estimating pitch period may be reduced and the quality of the audio data may be improved.