RE: Best practice for mp3s in ePubs?

Hi Jeff,

 

In the text you’ve cited, audio resources are marked as allowed to be remotely hosted above the line you’ve highlighted. It’s generally not a good idea to do that, though, as you’re more likely to have playback problems. It requires an active internet connection and a reading system that will retrieve remote resources. Not all do.

 

Using HTML’s native <audio> element is almost always a much better solution than rolling your own player via javascript. Aside from the potential pitfalls in making a custom player accessible, it also requires a reading system that supports javascript. Again, not all do.

 

In terms of making the player more accessible, you can add a name using aria-label. I believe that would also allow voice control software to pick out the player to activate, but I’m not able to test how well it works.

 

Here are a couple of pages from the DAISY knowledge base on these topics:

https://kb.daisy.org/publishing/docs/html/audio.html

https://kb.daisy.org/publishing/docs/epub/remote-resources.html

 

Matt

 

From: Wysebee Inc. <zxu@wysebee.com> 
Sent: May 12, 2025 3:34 PM
To: Ciporen, Laura <laura.ciporen@mheducation.com>
Cc: public-publishingcg@w3.org
Subject: Re: Best practice for mp3s in ePubs?

 

Hi Laura

 

Here is the spec https://www.w3.org/TR/epub-33/#sec-resource-locations



 

For naming of audio player to let voice control say "Play X" would require custom playback button with proper a11y label.

 

Hope it could help.

 

Cheers,

Jeff

 

On 2025-05-12 15:13, Ciporen, Laura wrote:

Thank you so much for your reply, Jeff.

Do you have a link to the specific spec that you are referring to? 

We aren’t running into problems with epubchecker, we are just not sure whether the concerns over requiring internet access override the concerns about file size or vice versa. Or, I suppose, if there is no real best practice on this and it’s just up to the creators of ePubs to decide for themselves which concern is most important. And we’re also wondering if there are specs around naming instances of the audio player. 

For example:

1. You have 10 different vocabulary words on a page and each one has an audio file where you can listen to how to pronounce the word.
2. Someone using voice control should be able to say “Play X” to have the correct audio play. But the play buttons aren’t going to visibly say anything besides “play” so I’m looking for whether there are best practices that would allow the voice control user to easily know what to say to play a specific audio file.

-Laura

 

 

 <http://www.mheducation.com/> 

Laura Ciporen, CPACC

Digital Content Accessibility Manager

McGraw-Hill | Higher Education

1325 Avenue of the Americas, 8th Floor, New York, NY 10019

P: 646-766-2269 

 <mailto:laura.ciporen@mheducation.com> laura.ciporen@mheducation.com

 <http://mheducation.com/> mheducation.com

 

      <https://www.accessibilityassociation.org/cpacccertification> 

 

From: Wysebee Inc.  <mailto:zxu@wysebee.com> <zxu@wysebee.com> 
Sent: Monday, May 12, 2025 2:04 PM
To: Ciporen, Laura  <mailto:laura.ciporen@mheducation.com> <laura.ciporen@mheducation.com>
Cc: public-publishingcg@w3.org <mailto:public-publishingcg@w3.org> 
Subject: Re: Best practice for mp3s in ePubs?

 

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Hi Laura

 

1. I believe based on current spec the mp3 files needed to be embedded in epub file.

2. I have not found any existing standard code for a default player. A very basic player should be the html mp3 player. I can help with creating some example (please feel free to reach out if need any help with creating example and testing)

3. I think basically need to pass epubcheck - the epub validation tool.

4. Might need a bit more details on the use case.

 

Cheers,

Jeff

 

On 2025-05-12 13:23, Ciporen, Laura wrote:

Hello, all.

I am wondering if there is an accepted best practice for including mp3s in ePubs? 

1. Which is best? 

1. Streaming (which requires users to be online) 
2. Packaging the files with the ePub (which greatly increases the file size)

2. Is there standard code for default players for mp3s in ePubs?

1. For a short player for tiny clips which would only have a single play/pause button.
2. Different code for a more complex player for longer audio which might also have ff, rewind, scrubbing, etc.

3. If not, are there particular controls that need to be included or avoided?
4. Either way, if there are multiple audio files on the same page (or in the ePub as a whole) is there a best practice for identifying each distinctly (primarily to support voice control users being able to easily indicate which audio they want to play).
5. Are there any other best practice considerations about including mp3s in ePubs?

1. (Besides the fact that there should be a text version of the content unless the entire point of an audio is to test someone’s ability to interpret the audio.)

Thank you ever so much!

-Laura

 

 <http://www.mheducation.com/> 

Laura Ciporen, CPACC

Digital Content Accessibility Manager

McGraw-Hill | Higher Education

1325 Avenue of the Americas, 8th Floor, New York, NY 10019

P: 646-766-2269 

 <mailto:laura.ciporen@mheducation.com> laura.ciporen@mheducation.com

 <http://mheducation.com/> mheducation.com

 

      <https://www.accessibilityassociation.org/cpacccertification> 

 

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