After demuxing a dvd it plays like slowmotion.

[brainstorm]

Hi

I want to add subtitles to a dvd movie.
But when i demux it with ifoedit end render it in dvdlab, movie plays like some kind of slowmotion and sound is not synchronize with video very well.
Source vob files of movie without demux plays normal.
I tried about 5 demux tools but result is tha same, but only on this movie, all other dvds with custom subs play normal.
Is it possible to add subs without demuxing or what to do?

Thanks