How to adjust subtitle position on screen

[dodo]

I use DVsubmaker to get .sub file from avi files and use SubtitleWorkshop to edit it and conver to .srt or .ssa files. I know how to adjust the position of subtitles for .ssa file, but don't know how to do it for .srt files. Any idea?
Also, what is the reason for the subtitle to flick? By the way, I just want to show date and time, I filled the gap between each line. For example
first line of subtitle start at frame 1 end at frame 30
second line of subtitle start frame 30 end at frame 60
However, the resulting subtitle still flick!
Thank you for your opioin!

[Baldrick]

you adjust srt settings in the video player or filter like vobsub / directvobsub or authoring tool you are using.