I have opened one of my pdfs in Acrobat and klicked on a Flash object. PDF gives me this advice:
Do you know of any converters Flash → ... which provides a format suitable for pdf embedding?
I do not know, if this helps.
In Wikipedia there are some alternatives listed:
(The English version has different content than the German version.)
... on a tangent here... when one inserts a mp4 file in FM, and publishes it as pdf - Acrobat needs Flash to play it. I wonder how that will work post 2020? ...