1-4-5
Blizzard Challenge 2018 NITech  A!.
1,211

68- C2(- C51 C"7 @1 C?*1 C+8,1
1

%&4"$ (NITech)2  3);/1AB$2018'<#:=9> 2018'9012/

¢ c83@ (TTS) "!& $%!&&& L6
.IA:u ec^%EK\#%9X]
bU7:u H>;R=+/M4'l DNN, LSTM, WaveNet, Char2Wav, Deep Voice, TacotronOu¢ TTS"Z);R&%%2T[dJNBG_5au Blizzard Challenge [Black et al. ’05]
l 10&",` ;R&ITTS"DPl (*S:VF(WZ)<dTTS"Z)u¢ NITech TTS"u2005?QYMc83@"C-2

Blizzard Challenge 2015−2018¢ u%92%9C=

3ETTS 4;¢ "?B *-A<1'
&Fl 2015, (!): 21G
l 2016,: 51G
l 2017, 2018,: 71Gu H)"$#>+(l @GDI@7
I0HB:u H)"58A +(l /.I"I6):u"I'm king of the jungle," roared Lion.
"I'm going to eat you all up."
"No!" cried the jungle animals.

Character1
Character2Descriptive part
3

NITech 2015−2018 TTS¢ NITech 2015 TTS

I-DF ;.?#
u 0;=,BE91H
u*4G2/'¢ NITech 2016 TTS

I-DF ;.?# @)7>
u 75A6,BE91H /'u GV%
!.? ,DNNIJ" /'u¢ NITech 2017 TTS& +A6 ,BE91H /'u <C"$8(: BE91H /'u GV%
!.? ,MDNIJ" /'u¢ NITech 2018 TTS#3'" /'u WaveNet#/'u4

NITech 2018 TTS system

5

NITech 2018 TTS system6!)F.#&¢ UJ8E_=u[2,R!)BW) DCVL!)4M⇒ >S) !)F.&0L #&¢ >S)

!)G?

/6Y<N$)!): _O%"'G?
u $)!)#&
HMM   IZ4Mu $)!)
PQ]^-+* ;8!)3?
u¢ !)F.#&Bi-directional gated recurrent unit (GRU)u .5`6Y(H6,XYKA\u 15`6Y@!)F. 9 (0 or 1)u>S)!)F.&0L7T
7

NITech 2018 TTS system

8

NITech 2018 TTS system

9

WaveNet-based vocoder¢ !,/%61#/Z[KCX@H JBMFu JBMFI
9FZ= :W45⇒ (/)+#/ A2u¢ WaveNet#/ [van den Oord et al.; ’16], [Tamamori et al.; ’17]

JB PG'+5.MF7Tu 3];\ Z=JB'+5u OU
X>5NM⇒ / -X>5A2u¢ &+")%</-X>5[Yoshimura et al.; ’18]
0Y SVKDREX>5
u Z=Q85
$!+*-A2 [Tokuda et al.; ’94]
u

^:W

Z=JB

MF?L
10

2O:( (1/3)¢ M0DF/1A&B-;@:(I41A&

1258&

MN=5J

12<*MFCC + Δ + ΔΔMN#

3>6 left-to-right !

CE#!

% GMM-HMM!#1A&.9H7L)

90%TTS1A&

924&

¢ &8+#:(+,=5J251<*CE=5JDNN#;GBi-directional gated recurrent unit,
33'K3P128 PReLU

1A

#"

Adam, $

? 20%11

+K6" (2/3)¢ >?F6"%9232 kHz

IJ;.E638#STRAIGHT L,2'5%92L
328# H%41$ + Δ + ΔΔ

C&2925C&

HMM7D

5<0 left-to-right MSD-HSMM¢ IJ6"%9232 kHz

IJ;.E638#STRAIGHT L,2'5%92L3):)/(L328# H%41$AB;.E

16858#DNN7D

Single-mixture density network,3- G-L8000L *@ SGD, = 60%LGV! *@12.?2' (3/3)¢ WaveNet&2'%#% +6132 kHz<,*8μ-law
γ=0.1, β=0.1

 &% "&
WaveNet $3;
WaveNet:)7/<-9$ #Dilation 1, 2, 4, ..., 512 35@
dilation, residual, skip256!%$=>$80984(=>7/<Adam13 Usborne Publishing  14NaturalnessMOSID

Similarity
MOSIDIntelligibility
WER
ID

4.8

A

4.5

A

11I

4.0

K

3.9

K

14E, O

3.7

J

3.6

J

15

D, G

3.5

I

3.5

I

16K

3.0

L, M

3.417

N

2.9

B

3.2

LB

18J

2.8

D

3.0

M

20

F
...

...

...

A: 
B, C, D, E: TTS
I: NITech TTS
Red line: NITech TTSTTS

15
Overall impression
MOS
ID

Pleasantness
MOS
ID

Speech pause
MOS
ID

Stress
MOS
ID

48

A

48

A

48

A

48

A

38

K

37

K

K

J, I

33

J, I

K, J
I

3634

36
3235

J

29

B

28L, B

31

D, G

33

I

28

L

26

M

30

E

30

D, G...

...
Emotion
MOS
ID...

...
Intonation
MOS
ID

Listening effort
MOSID

48

A48

A49

A

37

K

38

K37

K35

J

35

J, I

34

J33

I

31

B

33

I

28

D30

M

28

D...

...

...

16

NITech 2017  2018 TTS1;¢ WaveNet*#72+96?!+&
u 4></.
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u 49
$3+"l 049 $3 WaveNet)5 :u2017201817¢ Blizzard Challenge 2018

NITech TTS$5)! 0)
u WaveNet$0)
u /C9,ADK?7l B;3#E@J(3#6=3LH4
u NITech 2017  2018 TTS:Gl B;3#E@J(3.%l WaveNet$
>1&+*u¢ '2FI$ !$8<E!
u End-to-end"$0)
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