I found the answer. Maybe you guys nknow this already:
You can’t. Many years ago YouTube had a Flash-based API which allowed direct playback of an embedded video inside a parent SWF file (the only way to do it in a PDF), but it also allowed people to bypass the advertising, so they closed it down. The current API only supports HTML embedding for web pages.
The ’embed’ URL for sites like YouTube and Vimeo is a link to their web page, not to the video file itself (legally you cannot link directly to the video stream so we’re not going to explain how it might be done). Acrobat’s video player will only accept a URL that points to the video file or to an RTMP stream connector, which is why the URL must end in a valid extension such as “.mp4”
The only options are:
Embed the entire video file into the PDF – assuming you have a copy and have the rights to publish it. Easiest to do but the file size may be a problem.
Host the video file on your own website and put the HTTP link into the annotation dialog (simple but anyone can download a copy, so it’s not secure).
Stream the file using Adobe Media Server (secure but very expensive).
.
