John,
Do you have a trick for determining the start and end times, or do you calculate it with timecodes, or do you try numbers until they work?
I created a webpage called “Frames_to_Time” to convert “Framestamps” (HH:MM:SS;FF) to Normalised Times (0.0 to 1.0).
Frames_to_Time Utility
When creating some animations it helps to know what “normalised time” corresponds to a certain frame in the clip. A webpage has been created to enable users to input the frames in the format “HH:MM:SS;FF” (where “FF” is the number of the frame). This “framestamp” can be observed between the timeline and the preview screen.
It is particularly useful for example if you are creating a “subtitle” Overlay HTML filter, so you can synchronise the subtitles precisely with the video. This utlity can be found on my website (Shotcut - Elusien's Contributions) at Frames_to_Time. There is a description there of the workflow to use it.