Accessibility considerations for instructional video
March 5, 2015

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Today I watched one provided by Sonic Foundry (maker of Mediasite) that was worth the entire watch. However, if you don’t have 61 minutes or don’t want to give Sonic Foundry your contact info, I’m providing my notes (organized in themes – not in order presented in the video).

Link to the full webinar


Greg Kraus, University IT Accessibility Coordinator, North Carolina State University
Tol Khesin, VP Marketing, 3Play Media

What do we mean by video accessibility?

Video needs to be accessible for all types of disabilities:

  • visual
  • cognitive
  • physical
  • auditory

We all think of closed captioning, but you also have to consider whether the video player itself is accessible. Make sure the video player can:

1. navigate the video player with keyboard keys, and also
2. see where you are on the interface, if you’re navigating with keyboard keys

AblePlayer is a good, fully accessible player:

Video search: make sure your video player has this. The ability search the text of the cc or transcript in order to find and jump to where specific words are mentioned. increases video’s usability.

Disabilities are on the rise

Disproportionate to population growth. Why?

  • medical advances: premature babies now often survive, but with disabilities
  • decades of war: soldiers more likely to survive, but with disabilities


  • closed captioning vs. transcript: cc are time-coded
  • closed captioning vs. subtitles: cc assume the user can’t hear anything, so describe everything audible that conveys any type of information; subtitles usually just translate into a different language
  • closed captioning vs. open captioning: open captions are burned into the video so can’t be turned off.
  • post-production captions vs real-time captions (real-time captions are created in real time)
  • audio descriptions

Audio descriptions

Difficult, an art. Attempts to insert descriptive audio right in with the rest of the audio track. Not always the best solution; you may just need to provide a properly formatted Word doc to visually impaired viewers so they can follow along (e.g., with math equations, may be impossible to insert audio descriptions meaningfully within the audio track)

Captioning costs

  • 1 hour of video will be ~$150 to have a professional caption it
    (professionals are faster; 3:1 for an amateur captioner, versus 5:1 for a professional captioner)
  • a single semester-long course can cost $8K to have captioned
  • how to plan for captioning? reactive and proactive captioning. (reactive for students who have a demonstrated need. proactive for students where there are high-enrollment courses)

How to associate a caption file with a video

~50 different captioning formats. SRT is most common and is used by YouTube. Currently, speech recognition (like what YouTube uses to produce automatic captions) produces about 60% accuracy. 1 out of 3 words is wrong (“spectacularly wrong”)

Most common method: create a “sidecar” file. submit both the video file and the sidecar file to the media server or player, and the video player renders the captions on top of the video

You may have to manually encode the captions with the video. (didn’t describe well the difference between these 2 options)

It’s also possible to burn the captions into the video – this is least popular because it is more difficult/complicated

Accessibility laws, regulations

(min 28 – 34 of the webinar) = really interesting stories of development of accessibility laws, ending with CVAA, which holds that whoever is the holder of the copyright for a video is also responsible for the cc

4 criteria for cc quality

July 2014, FCC came up with standards for cc quality. 4 criteria:

  1. Caption quality. Needs to be 99% flawless (post-production captioning)
  2. Captions need to coincide/sync flawlessly with the content
  3. Captioning must be beginning to end (i.e., run the entire length of the video)
  4. On-screen caption placement: where captions occlude important info that appears on the screen, they need to be relocated outside the lower third

Additional benefits of transcripts & captioning

  • 80% of people who use captions don’t have any sort of hearing disability!! (BBC Office of Communications study findings)
  • transcripts increase SEO (7.3% increase in video views when you include cc)
  • 50% of students used transcripts as study guides (39:40)

Last question

The one question I had that this video did not answer was: do we need to provide both a transcript AND closed captioning for video?

According to WebAIM:

“In order to be fully accessible to the maximum number of users, web multimedia should include both synchronized captions AND a descriptive transcript.”