I recently used Chronos to change frame rate but not speed adjust an hour long clip, converting the frame rate from 29.97p to 25p, which as we all know is a difficult conversion to make.
Chronos did an exceptionally good job, albeit inconstant in places with occasional artifacts, but on the whole, most of it was passable.
However, It’s not preserving the speed of the video which it is stating it is doing, rather, it’s slightly shortening it over the span of 1 hour so that by the end of that conversion clip, my cut points for lip sync clips were 27 frames early.
I was thinking of trying that with some videos I have but decided to retain the original frame rate due to the 29.97 trickyness.
I did try it increasing frame rate though on a 29.97 fps DVD containing a background screen seemingly playing at 25 fps - so the background screen annoyingly judders. In the end I did manage to improve things by increasing the frame rate in VEAI to 4 x 29.97 i.e. 119.88 fps - the extra frames created by VEAI somewhat smoothed the background juddery video screen. I’m next going to see what happens when I reduce from there back to 25 fps tonight - maybe it’s worthwhile doing your conversion indirectly in a similar way, just to see if it helps?
Incidentally, I notice that your 27 frames is exactly 25% of the difference between a 1 hour video at 29.97 and 30.00 fps… hmmm…