Simple answer is - you can't. Embed codes are HTML, you need the raw video stream URI, and comply with all the authentication routines that the host applies to stop people stealing it.
The detailed answer is that while it's possible at a technical level to integrate a custom Flex playback widget with the YouTube API, it really doesn't work properly because of the way YouTube have configured their security settings.
The most reliable (and simplest) solution is to host the streaming video on an Adobe Media Server instance (delivering it via RTMP) as that's handled natively by the video tools in Acrobat Pro; but it's certainly not cheap.
Dave, thank you for the prompt response.
Bumping an old thread but...
So this is a definite no to streaming youtube videos within a pdf? Annoying but fair enough - just wish adobe were clear that this just isn't possible.
I'm trying desperately to put together a book that I can use to share images and video without a large file size to pcs. Any pointers on what format I could try? Some sort of HTML package? (I'm a music teacher not anything IT...) flash? I've no idea where to start!
No where does it say in the Adobe documentation or in PDF documentation that streaming YouTube videos are supported in interactive PDF.
Since you originally wrote your message two workflows have emerged which you should explore: Fixed Layout EPUB and the Publish Online feature of InDesign CC 2015. Start by reading about them in the Help files.