Hello, I’ve been experimenting new export files and can’t seem to figure out how to get fallbacks for media placed with the [audio] and [video] shortcode to work in ePub and ePub 3.0. As an example, this test page -https://osu.pb.unizin.org/csstesting/chapter/chapter-1/ - has fuctioning fallbacks for the H5P object and iFrame (Youtube video), but not the embedded video or audio files.
All of the fallbacks work fine in the PDF file. This only seems to be happening with ePubs. The error code I’m getting is:
_ERROR(MED-002): /var/www/osu/wordpress/wp-content/uploads/sites/89/pressbooks/exports/Test-Book-1521479769.3.epub/OEBPS/chapter-001-chapter-1.xhtml(43,11): Audio element doesn’t provide fallback.
Is this something I am doing wrong and need to rectify or something that needs fixed in the export script?
I generated some new files and noticed that the epub2 does actually include the fallbacks. Perhaps I accidentally opened the epub3 file twice earlier. The media placeholders in the epub3 do not play anything and the files are not there when I unzip the epub, so the issue actually seems to be that the files that should be embedded are not being bundled during export.
The only thing that jumped out to me when I was attempting to re-embed was the Attachment Display Settings dropdown, which is set to embed for all of these. Don’t know if that would make any difference.