add times in timelines

I have to write film scripts. The chapters of a film script will take time (minutes, seconds). The outline-mode in Scrivener 3 is helpful. But what I am missing is the possibility to see how long all chapters of my film script are. In the metadata there is field “date”, but this is not helpful for me - I would need a field “duration in minutes and seconds” plus a possibility to see the addition of all my chapters in a script. That would be very helpful to control how long all my entries are. Or is there a workaround for this? Thanks a lot!

I use Aeon Timelines to keep track of that, when working in Scrivener. Picked it up cheap after a NaNowrimo one year.
There was a request for thoughts about integrating it with Scrivener a couple of years back, but I don’t know if anything came of that.

Custom metadata?

Of course I could use a metadata-field “text” to notice minutes and seconds (= duration of scenes). But there is obviously no possibility to summate these entries. For example: If I plan scenes in minutes and seconds, it would be very helpful how long all scenes are. If have a broadcasting time of (e.g.) 30 minutes, it would be very nice to see, how long all my scenes are. Of course, I could use an external calculator. A bit inconvinient.

Thanks a lot. I use Aeon as well, but it would much more comfortable to have this function in Scrivener.