Incorrect youtube srt subs timing information

[gradha]

Running a command like youtube-dl --skip-download --write-sub "https://www.youtube.com/watch?v=_tYG-COpn5w" yields an .srt file with many timings using the same time for end position as start position. In contrast, downloading the same subs with software like http://google2srt.sourceforge.net works fine. Here's a extract of the diff for these two versions:

--- bad.srt 2014-02-25 10:09:02.000000000 +0100
+++ good.srt    2014-02-25 10:12:48.000000000 +0100
@@ -1,345 +1,345 @@
 1
-00:00:04,581 --> 00:00:04,581
+00:00:04,581 --> 00:00:05,894
 Hello, I'm Sunmi

 2
-00:00:05,894 --> 00:00:05,894
+00:00:05,894 --> 00:00:06,621


 3
-00:00:06,622 --> 00:00:09,302
+00:00:06,621 --> 00:00:09,301
 I'm back with my new song after 7 months

 4
-00:00:09,302 --> 00:00:09,302
+00:00:09,301 --> 00:00:15,420


 5
-00:00:15,421 --> 00:00:15,421
+00:00:15,420 --> 00:00:17,637
 This time, my concept is vampire

[jaimeMF]

We are just downloading the srt file from Youtube, from their description it seems that google2srt converts to srt from other format (which, I guess, has the right timing). That may be the reason.

[xubuntu4iran]

Maybe an algorithm applied:
bad:
1
time1 time2
2
time3 time4
3
time5 ...
good:
1
time1 time3
2
time3 time5-0.001
3
time5-0.001 ...