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EPUBCheck · Images, audio and media overlays

EPUBCheck MED-005: non-standard overlay audio

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EPUBCheck MED-005 is an error message: “Media Overlay audio reference … to non-standard audio type … found.” A media overlay points to an audio file that is not a core audio type. Narration in media overlays must use MP3, AAC in an MP4 container, or Opus in an Ogg container; EPUBCheck names the file and its type.

The official message

Media Overlay audio reference %1$s to non-standard audio type %2$s found.

Default severity
Error. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.
EPUBCheck version
5.4.0

%1$s, %2$s… are filled in with the file, value or element EPUBCheck found.

Typical causes

  • Narration recorded or exported as WAV, FLAC or another format.
  • An audio file with a wrong media type in the manifest.

How to fix it

  1. Convert the narration to MP3 (audio/mpeg) or AAC in MP4 (audio/mp4).
  2. Update the src of each audio element in the SMIL file and the manifest item with the new file and media type.
  3. If the format is right and only the manifest media type is wrong, correct the media type.
  4. Rebuild the EPUB and run EPUBCheck again to confirm the message is gone.

When it's not this

If the audio URL has a #fragment, the error is MED_014.

Terms used here

Other MED messages

  • MED-004 Image file header may be corrupted.
  • MED-003 Picture "img" elements must reference core media type resources, but found resource "…" of type "…".
  • MED_007 Picture "source" elements must define a "type" attribute when they reference foreign resources; found resource "…" of type "…".
  • MED-008 The time specified in the clipBegin attribute must not be after clipEnd.
  • MED-009 The time specified in the clipBegin attribute must not be the same as clipEnd.
  • MED_010 EPUB Content Documents referenced from a Media Overlay must specify the "media-overlay" attribute.

Sources

Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EpubCC.

FAQ

What does EPUBCheck MED-005 mean?

EPUBCheck MED-005 is an error message: “Media Overlay audio reference … to non-standard audio type … found.” A media overlay points to an audio file that is not a core audio type. Narration in media overlays must use MP3, AAC in an MP4 container, or Opus in an Ogg container; EPUBCheck names the file and its type.

Is MED-005 an error?

MED-005 is reported as error by default. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.