AFAIK, right now only iBooks has any support for audio and video in Epub.
You should test it out on your iPad.
This is my first ebook...how to I test it out on my iPad?
Also, Sigil does not know about the HTML5 tags and strips them out as soon as you open the ePub.
Sigil does a lot of stuff without anyone asking it to. I quickly abandoned it in favour of a simple text editor for my e-diting.
Hey guys, I'm having a similar problem, I place an anchored mp4 video in my file and it doesn't appear on iBooks at all. I've tried encoding through Media Encoder to the H.262 standard and nothing, I've tried placing it outside text boxes, I've tried different formats-nothing. Any suggestions?
The problem with CS5.5 is that there is a bug which was never fixed.
From my InDesign Magazine article Oct./Nov. 2011 #44:
"Anything you set in the Media panel will be lost when you export to EPUB, which makes some tasks much more difficult. For example, to include a poster image,
you must add a reference to the poster image in the <video> tag, add the poster image file to EPUB images folder, and edit the manifest in the content.opf file
to include the video file. For information on editing EPUB files, see Gabriel Powell’s article “Editing eBooks” in InDesignMagazine #32 and Elizabeth Castro’s eBook "EPUB: Straight to the Point". www.elizabethcastro.com/epub
The problem is fixed, and it works fine in InDesign CS6.