EpubCCEPUBCheck OPF-036: video type may not play
Updated:
EPUBCheck OPF-036 is a usage message: “Video type "…" might not be supported by reading systems.” A video uses a media type that reading apps may not support. This is a usage note (shown with -u), and EPUBCheck suggests video/mp4, video/h264 or video/webm instead.
The official message
Video type "%1$s" might not be supported by reading systems
EPUBCheck's suggestion: Use "video/mp4", "video/h264" or "video/webm" instead.
- Default severity
- Usage. Informative only and hidden by default: it appears when EPUBCheck runs with -u (--usage). It does not make the EPUB invalid.
- EPUBCheck version
- 5.4.0
%1$s, %2$s… are filled in with the file, value or element EPUBCheck found.
Typical causes
- Video exported in a less common container or codec, such as Ogg or QuickTime.
- Video copied from a website in whatever format the site used.
- A manifest media type that does not describe the real file.
How to fix it
- Check which formats the reading apps you target can play.
- Re-encode the video as MP4 (H.264) or WebM if you need it to play widely.
- Update the manifest item's media-type and the source element's type attribute to the new format.
When it's not this
If the video is placed directly in the spine, the rules for spine items and fallbacks (OPF-043) apply as well.
Terms used here
Other OPF messages
OPF-035Media type "text/html" is not appropriate for XHTML/OPS.OPF-037Found deprecated media-type "…".OPF-034The spine contains multiple references to the manifest item with id "…".OPF-033The spine contains no linear resources.OPF-032Guide references "…" which is not a valid "OPS Content Document".OPF-040Fallback item with id "…" could not be found.
Sources
Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EpubCC.