Recovery of Missing Speech Packets Using the Short-Time Energy and Zero Crossing

Measurements

Nurgun Erdol, IEEE, Claude Castelluccia, and Ali Zilouchia

n, Senior Member, IEEE

Hung, Kuo-En NTHU/CS, Visual Communication Lab.

Outline

• Introduction

• Waveform Substitution Based on the STE and the Zero-Crossing Information

• Experimental Results

• Analysis and Evaluation of the Reconstruction methods

• Conclusions

Introduction

• Short-time energy (STE)

• Zero-crossing Rate (STZR)

• Zero-crossing Locations (STZL)

Introduction (cont’d)

Waveform Substitution

2/)1(,...,,2/,0,11

isn Segment

1,...,1,0,by k packet in samplesSpeech

1

0

2 MnMMnnxM

n

Pllx

M

tkk

k

Waveform Substitution (Method A)

Method A (cont’d)

packet previous theof samplelast on the basedsign initial thesets:sgn[]

sin()factor adjacent on the changessign impose:)1(

1),(in support unit with r windowrectangula a is:

)()(

)()()(

10 ,)(

)sin(

)1()1(sgn)(

kpacket in STZL therepresent :,...,1 ,

1

01

i

iii

k

cr

ii

ii

i

Z

i

ikc

i

nnw

nne

nxnenx

Pnknnw

nn

nn

Pxnx

Zin

Waveform Substitution (Method B)

Method B (cont’d)

)()(

)()()(

))(sin()( 0

nne

nxnenx

nnZnx

k

cr

c

Waveform Substitution (cont’d)

zz

kkr

zzz

zZkr

kkr

kr

nPnnn

xPexPx

Pnnnn

nnPxnenx

PxePxx

nnnn

nnPxnenx

2;2

)0()( and )0()(

1),sin()1)](1(sgn[)()(

)1()1( and )1()1(

0),sin()]1(sgn[)()(

110

11

11

11

101

01

Experimental Results

• Parameters(a) Packet loss rate

(b) Packet length

(c) STE window length

(d) Interpolation technique

Experimental Results (cont’d)

Experimental Results (cont’d)

Experimental Results (cont’d)

Experimental Results (cont’d)

Experimental Results (cont’d)

Experimental Results (cont’d)

Experimental Results (cont’d)

dBeYeXeXMSNR

dBinyinxinxI

nSNR

N

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i

jw

I

i

l

i

iii

22/

0

22/

0

1

2

1

2

])()([)(log10

)]()([)(1

log10)(

Experimental Results (cont’d)

:Method A

: Method B

: Zero-stuffing

Experimental Results (cont’d)

Experimental Results (cont’d)

Conclusions

• STE and STZL’s of a speech segment in a packet are sufficient parameters for reconstruction.

• Method A can be used until the packet loss rate get up to 40%

• Provide a smooth transition in energy