I’m wondering if it has something to do with the TimeCode in the video, or perhaps a Drop Frame / Non-Drop Frame Setting somewhere, or perhaps both. I marked all the subtitle tracks as “Non-Drop Frame” but I see in the properties Window of the Authoring software that it lists the Start and end times for both Drop Frame and non-Drop frame and that they are quite different. The last subtitle in Drop frame mode is 01:58:50:06, while in non-drop frame mode it is at 01:58.41.08, a difference of about 9 seconds. So, if by the end of the film the subtitles are 9 seconds early, perhaps I need to mark them as Drop Frame?