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Jhing-Fa Wang, Fellow, IEEE, Jia-Ching Wang, Jar-Ferr Wang, and Jian-Jia Wang

A Voicing-Driven Packet Loss Recovery Algorithm for Analysis-by-Synthesis Predictive Speech Coders over Internet. Jhing-Fa Wang, Fellow, IEEE, Jia-Ching Wang, Jar-Ferr Wang, and Jian-Jia Wang IEEE Transaction on Multimedia, VOL. 3, NO. 1, March 2001. Outline. Introduction

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Jhing-Fa Wang, Fellow, IEEE, Jia-Ching Wang, Jar-Ferr Wang, and Jian-Jia Wang

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  1. A Voicing-Driven Packet Loss Recovery Algorithm for Analysis-by-Synthesis Predictive Speech Coders over Internet Jhing-Fa Wang, Fellow, IEEE, Jia-Ching Wang, Jar-Ferr Wang, and Jian-Jia Wang IEEE Transaction on Multimedia, VOL. 3, NO. 1, March 2001 Chin-Kai Wu, CS, NTHU

  2. Outline • Introduction • Analysis-by-Synthesis Predictive Coders • Voicing-Driven Packet Loss Recovery Algorithm • Multiresolution Excitation Generation • Pulse Tracking Procedure • Experimental Results • Conclusion Chin-Kai Wu, CS, NTHU

  3. Analysis-by-Synthesis Predictive Coders Codebook Index LPC parameter Gain aperiodic Total Excitation periodic Chin-Kai Wu, CS, NTHU

  4. Voicing-Driven Packet Loss Recovery Algorithm nearest half previous frame Chin-Kai Wu, CS, NTHU

  5. Multiresolution Excitation Generation • Reason to use wavelet transform • Good time-frequency localization • Multiresolution characteristics • Revealing some characteristics that other signal analysis techniques miss Two-stage two-band Wavelet analysis filter banks cj: scaling coefficient dj: wavelet coefficient h(n): Lowpass filter coefficient g(n): Highpass filter coefficient Chin-Kai Wu, CS, NTHU

  6. voiced unvoiced Multiresolution Excitation Generation (Cont’d) Chin-Kai Wu, CS, NTHU

  7. Multiresolution Excitation Generation (Cont’d) Chin-Kai Wu, CS, NTHU

  8. Pulse Tracking Procedure • Pulse Position Tracking Algorithm • Pulse Amplitude Estimation Algorithm Chin-Kai Wu, CS, NTHU

  9. Pulse Position Tracking Algorithm (Step 1) • Find the maximum absolute value within the frame and denote its position as P (peak position) tracking • Set all sample with opposite sign to zero Chin-Kai Wu, CS, NTHU

  10. Pulse Position Tracking Algorithm (Step 2) • Construct a clipper by defining the clipping level from the maximum absolute value • Set samples below the clipping level to zero Chin-Kai Wu, CS, NTHU

  11. Pulse Position Tracking Algorithm (Step 3) • Record peak position P and set a clearing region to reset all the samples within the region to zero Chin-Kai Wu, CS, NTHU

  12. Pulse Position Tracking Algorithm (Step 4) • Repeat Step 1 to 3 to recorder all the recorded peaks according to the positions and denote them as {p1, p2, …, pNp} Chin-Kai Wu, CS, NTHU

  13. Pulse Position Tracking Algorithm (Result) Chin-Kai Wu, CS, NTHU

  14. Slope of where Pulse Amplitude Estimation Algorithm (Step 1) • Compute the trend slope associated with the envelope of the speech peaks Np: Number of peaks Chin-Kai Wu, CS, NTHU

  15. Pulse Amplitude Estimation Algorithm (Step 2) • Estimate the pulse position of the missing frame. Let be the set of estimated pulses, where Chin-Kai Wu, CS, NTHU

  16. Pulse Amplitude Estimation Algorithm (Step 3) • Estimate the envelope of the speech peaks in the missing frame • Track the amplitude of each excitation pulse Chin-Kai Wu, CS, NTHU

  17. Pulse Amplitude Estimation Algorithm (Result) Chin-Kai Wu, CS, NTHU

  18. Experimental Results Chin-Kai Wu, CS, NTHU

  19. Experimental Results (Cont’d) Chin-Kai Wu, CS, NTHU

  20. Conclusion • Packet loss degrades the speech quality of the analysis-by-synthesis coders seriously since the loss parameters not only affect the current speech frame but also produce error propagation problem • The proposed recovery algorithm estimates the excitation information in the missing frame more accurately due to the selection of different excitation generation models Chin-Kai Wu, CS, NTHU

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