Media9 is becoming obsolete Dec 2020 due to Adobe dropping Flash support. Is there any replacement out there that does not rely on Flash that will allow the inclusion of video and audio in latex documents?
Official Adobe documents on embedded multimedia support (MP4/h.264 video, MP3 audio) in PDF, such as https://helpx.adobe.com/acrobat/using/adding-multimedia-pdfs.html, are still Flash-centric. Thus, it seems Adobe have not yet decided on the future of multimedia in PDF beyond Flash EOL. Maybe, they are working on it, but nothing has been disclosed to the public yet.