Mp4s don’t appear in exported swfs in indd 2018
The mp4s did work in indd 2017 and they do still in epub preview. I made identical indd files in 2017 and 2018 and placed several MP4s in both. they all worked in 2017 but in 2018 when activated by a click, button, or controller the poster disappears and the mp4 doesn’t play.
This happened at school some students were working on the classroom 2017 macs and others their own 2018 windows and mac laptops the test I ran was on windows 10
Please update to InDesign’s latest update, Id 13.1 for the fix of the problem.