Duration in filelist starts with -2?

[OnceJune]

Hi, thanks for sharing the code.
When I tried to run lightspeech on my own dataset, I found in sample file list, the sum duration always starts from -2:

LightSpeech/filelists/valid_filelist.txt

Line 1 in d9290f7

printing in the only sense with which we are at present concerned differs from most if not from all the arts and crafts represented in the exhibition|-2 1 4 14 16 22 35 56 66 78 84 87 97 106 114 117 126 140 150 158 166 171 174 179 182 187 195 203 209 218 227 234 239 248 252 255 261 268 271 274 282 286 290 296 308 329 334 341 377 384 390 399 413 431 433 439 441 444 452 457 472 481 487 490 500 507 516 525 529 532 535 542 566 571 576 584 592 596 605 610 614 617 619 630 633 647 656 662 670 679 683 690 693 696 705 709 712 718 723 727 742 745 748 757 762 770 777 781 787 796 805 811 829|3 3 10 2 6 13 21 10 12 6 3 10 9 8 3 9 14 10 8 8 5 3 5 3 5 8 8 6 9 9 7 5 9 4 3 6 7 3 3 8 4 4 6 12 21 5 7 36 7 6 9 14 18 2 6 2 3 8 5 15 9 6 3 10 7 9 9 4 3 3 7 24 5 5 8 8 4 9 5 4 3 2 11 3 14 9 6 8 9 4 7 3 3 9 4 3 6 5 4 15 3 3 9 5 8 7 4 6 9 9 6 18|P R IH1 N T IH0 NG pau IH1 N DH IY0 OW1 N L IY0 S EH1 N S W IH1 DH pau W IH1 CH W IY1 AA1 R AE1 T P R EH1 Z AH0 N T K AH0 N S ER1 N D pau D IH1 F ER0 Z pau F R AH1 M M OW1 S T IH1 F N AA1 T F R AH1 M AO1 L DH IY0 AA1 R T S AH0 N D K R AE1 F T S R EH2 P R IH0 Z EH1 N T IH0 D IH1 N DH IY0 EH2 K S AH0 B IH1 SH AH0 N|LJ001-0001.wav

While when I check the guide in README:
https://github.com/ivanvovk/DurIAN#6-how-to-align-your-own-data
Found that the given file list have sum durations starts from 0:
https://github.com/ivanvovk/DurIAN/blob/a708e9c5bb89895ddf08ca1a13bc8fd683b1e23f/filelists/valid_filelist.txt#L1
So my question is, how did the -2 comes from? I now completed with MFA and tried to build file list, should I add a -2 at the very beginning?
Thanks in advance.

[OnceJune]

And why bit depth is 9?

LightSpeech/configs/default.yaml

Line 30 in d9290f7

bits : 9 # bit depth of signal