Subtitles in the same second are considered to overlap

[thomas.petazzoni@…]

If I create a subtitle file with two successive subtitles, with the ending time
of the first one in the same second as the starting time of the second subtitle,
MPlayer seems to considered them as overlapping. As a result, it undisplays the
first subtitle after 7 seconds, unless the -overlapsub option is selected.

For example, use this subtitle file on any video:
1
00:00:00,570 --> 00:00:15,251
Blablablablabla subtitle 1

2
00:00:15,252 --> 00:00:17,000
Pouet Meuh Chouette

The first subtitle should be displayed during 15 seconds, but it disappear after
7 seconds. The -overlapsub option disabled this behaviour, and the first
subtitle is correctly displayed during 15 seconds.

However, if you change the starting time of the second subtitle to be
00:00:16,252, then the first subtitle is properly displayed during 15 seconds,
even without the -overlapsub option.

I think that two subtitles should be considered as overlaping if they really
overlap, not if they are in the same second.

I'm using 1.0rc1-4.1.2 on Debian unstable.