I'm certain that I successfully achieved this a couple of years ago, but I'll be darned if I can replicate it now, and I wonder if something in the underlying PDF engine of Preview.app has changed in the interim. Here's the situation:
I'm creating a PDF (originated in InDesign, 2018 version) that includes embedded video media. In Acrobat the video shows its designated poster image (defined by a file rather than by a frame of the video) which is basically a big 'Play' symbol, and clicking on that plays the video as expected. However, when the PDF is viewed in another PDF reader like Preview.app (I'm on a Mac) the user is invited to click, but clicking has no effect (which is expected behaviour, but not very good UX).
Previously, I solved this by placing an alternative 'faux poster' image directly over the video, explaining that video would only play inside Adobe Acrobat. Once exported and viewed in Acrobat, Acrobat would place the media (video) element on top of all other content, so the user would see the 'click here' image. In Preview.app, on the other hand, video content was not recognised as being anything special and so the 'faux poster' image remained at the top of the content stack and the user was informed that they would need Acrobat if they wanted to watch the video. Much nicer user experience.
Now things seems be different; Preview.app doesn't play the video, but it does put the video element to the top of the stack, thereby hiding the 'You need Acrobat' panel. Result is bad UX again.
Does anybody have a way to achieve what I'm trying to achieve (Acrobat invites the user to click and then plays the video, whilst Preview.app just shows them a 'You need Acrobat' image)?