This is the message I am getting: 'The HTML5 widget wasn’t added because it contains a media file that isn’t in a supported format'.Video files are ok, audio files are in .mp3 format. What can be the problem? any idea?
iBooks Author requires .m4a files for audio and .mp4 for video. Does it work when you change this format?
Thank you very much. I have made the file names without any spaces and this helped.
Im having the same problem.
Have you tried removing spaces or other non-aphanumeric characters from the filenames?