In the previous version of VLC I had installed, I was able to adjust the subtitle timing (by subtracting time in tenths of seconds from what appeared in the SRT or SUB file) so that it would match the dialogue precisely.
In this new version, I can't get the subtitles time adjustment to work at all. No matter what figure I enter, there is no resulting change in when the subtitles start when viewing the film with subtitles on. Also, it's not possible to enter negative values -- in the old version I had (8.6 I think) you could do that, so that if the SRT file had the subtitles starting too late at 1:22 when the dialog really started at 0:54, you could adjust it to start at 0:54 by entering a figure to make it start 26 seconds earlier (by entering "-260" -- it was a bit counterintuitive since it was in tenths of seconds, not seconds, but I guess that's needed for fine tuning and difficult to program decimal points). In the current version, 9.9, it seems to be in full seconds -- there's no indication otherwise. And like I said, no possibility of entering any figure lower than zero -- which I suppose means subtitles can be adjusted to start later than they normally would but not earlier.
I'm not finding any good documentation on how this works in the current version.