I'm trying to figure out what goes on behind the scenes when one creates an Interactive PDF from InDesign 2021. For instance, the following was true when creating Interactive PDFs from CS5:
"When you export an interactive PDF from InDesign CS5, included media is written to the Rich Media Annotation Layer, which means the content is played back via the embedded Flash Player within Acrobat Pro 9 or Adobe Reader 9 or higher."
Now that Flash is dead and can't be played back in Acrobat Pro DC, I'm assuming rich media is no longer played back with the Flash Player, as there is no embedded Flash Player. So what is Acrobat Pro DC using to play back rich media now? Is Rich Media still written to the Rich Media Annotation Layer of the PDF when InDesign exports using Interactive PDF?
Well, I'd ask that in one of the Acrobat forums.
A lot has changed with Acrobat Pro since the days when InDesign CS5 was made available.
InDesign: Beginning with InDesign 2020 all Flash related stuff was removed.
( ACP )
There is no way I can possibly recommend using any kind of multimedia in PDF anymore. There are just too many gotchas beginning with the fact that there are scores of substandard PDF readers.
Don't worry...I'm not interested in creating an Interactive PDF. I'm trying to understand how they work, and specifically, how they differ now (if at all) than in the days of CS5.
Maybe you might get what you are seeking from the PDF Association:
"We are an international collaboration of member organizations and individuals actively learning from and supporting each other in the development and use of PDF technology.
We invite developers of PDF solutions; companies that work with PDF in the document and enterprise content management (ECM) context and users who want to advance their implementations of PDF technology, to join, learn from and contribute to our efforts."