1. 2001/05/24Chin-Kai Wu, CS, NTHU1 Improved frame erasure concealment for CELP-based coders Juan Carlos De Martin, Takahiro Unno, Vishu Viswanathan DSPS R&D, Texas Instruments Dallas, Texas Acoustics, Speech, and Signal Processing, 2000. ICASSP '00. Proceedings. 2000 IEEE International Conference on, Volume: 3, 2000

2. 2001/05/24Chin-Kai Wu, CS, NTHU2 Outline Introduction G.729 Decoder Concealment in G.729 Repetition-based Concealment Muting of Excitation Signal Jittering of Pitch Delay LPC Bandwidth Expansion Interpolative Concealment Experiment Result

3. 2001/05/24Chin-Kai Wu, CS, NTHU3 Introduction G.729 Decoder

4. 2001/05/24Chin-Kai Wu, CS, NTHU4 Introduction (Cont’d) Concealment in G.729 Replaces the missing excitation signal with one of similar characteristics, while gradually decaying its energy Specific steps Repetition of the synthesis filter parameters Attenuation of adaptive and fixed-codebook gains Attenuation of the memory of the gain predictor Generation of the replacement excitation

5. 2001/05/24Chin-Kai Wu, CS, NTHU5 Repetition-based Concealment Proposed Decoder Pitch Delay Jitter Generator GeGe LPC Bandwidth Expander

6. 2001/05/24Chin-Kai Wu, CS, NTHU6 Muting of Excitation Signal G.729 Proposed Muting Factor Muting Counter

7. 2001/05/24Chin-Kai Wu, CS, NTHU7 Muting of Excitation Signal (Cont’d)

8. 2001/05/24Chin-Kai Wu, CS, NTHU8 Jittering of Pitch Delay G.729 Previous pitch delay increased by one Accumulate the estimation error Proposed Repeat pitch delay in the bad frames Random jittering of 3% is added

9. 2001/05/24Chin-Kai Wu, CS, NTHU9 LPC Bandwidth Expansion G.729Repeat LPC parameters in the last good frame Proposed Bad frame applied to last good frame Good frame applied to received good frame

10. 2001/05/24Chin-Kai Wu, CS, NTHU10 Interpolative Concealment

11. 2001/05/24Chin-Kai Wu, CS, NTHU11 Interpolative Concealment (Cont’d) Adaptive Codebook Parameter Gain was interpolative between past and future parameters Median smoothing was applied to codebook index. Voice classification is the same manner as in G.729 Fixed Codebook The same as G.729

12. 2001/05/24Chin-Kai Wu, CS, NTHU12 Experiment Result Repetition-based Concealment Proposed method does not work well on large packet Improvement is clearer for female speakers than male speakers

13. 2001/05/24Chin-Kai Wu, CS, NTHU13 Experiment Result (Cont’d) Interpolative Concealment