Fixed-Layout EPUB with Media Overlay: Audio Not Playing

[ricky0web]

Hello. I am attempting to create a fixed-layout EPUB with Media Overlay support. However, it is not functioning as expected. Below is a description of the work I have done and the issues I am encountering.

Implemented Steps:

Used InDesign to add images for each dialogue over a single-page comic.
Exported the EPUB using InDesign.
Created an audio folder and stored mp3 files in it.
Prepared a SMIL file, linking XHTML file IDs with mp3 files and specifying the start and end times for each dialogue's audio.
Specified each item in the <manifest> tag of the OPF file.
Zipped all files using 7zip and changed the extension to .epub.
Confirmed Issues:

Opened the EPUB file in Adobe Digital Editions, but the audio did not play.
Opened the EPUB file in Thorium Reader, but the audio did not play.
Attempted Solutions:

Entered alt="alternative text" and found that Thorium Reader played the phrase "alternative text" for each dialogue.
Note:
I have uploaded the created files and the EPUB file to GitHub.
https://github.com/ricky0web/mediaoverlay_fix

[DNSB]

I would suggest looking at several working epub3 files with audio (see A Christmas Carol audiobook for example). Overall, your method of using InDesign and then trying to manually add files is simply asking for errors.

Running epubcheck on your epub came up with multiple errors, most of which were due to having files manually deleted from the epub but a couple were more severe such as the missing media-overlay attribute:

OEBPS/content.opf	17	1090	Col: 97: ERROR(MED_010): EPUB Content Documents referenced from a Media Overlay must specify the "media-overlay" attribute.
OEBPS/toc.xhtml	9	245	Col: 9: ERROR(RSC-005): Error while parsing file: element "ol" incomplete; missing required element "li"