I have all the subtitles timed correctly on my .srt. The timecodes (ex, 01:40:34,841 --> 01:40:37,319) correspond to the video no problem. However, after authoring with ifoedit, tbe subtitles are okay for about 45 minutes or so or so, then a delay starts to happen and after about an hour or an hour and a half, the timing becomes gradually off (the subtitles start appearing about a second early, then 2, 3, 4 seconds, etc) It's really strange because on the srt, there is no such problem. I use txt2sup for the conversion, but I doubt that's the problem. Anyone has an idea what the problem is?
May be that there is some problem when you try to save that .srt to .sup format. Might be also timing thing. Are u sure that subtitle file is using same fps that the movie? Try Avi2DVD or ConvertXtoDVD...