The best way to make video accessible is by offering open captions that everyone can see and a descriptive audio track for the visually impaired. However, closed captions or even a linked transcript can be helpful if open captioning is not an option.
For videos offered on the Web it's important to choose a format that's popular and widely supported in browsers. Formats change frequently: it is best to research video plug-in statistics for current browsers before selecting a final format for delivery.
TechTV Now Supports Captions
We're happy to hear that TechTV has recently launched its player with support for captioning. This means anyone at MIT can add captions to the video content they're sharing on TechTV. Free tools for creating captions are listed below. Or, you may opt to have TechTV outsource your captioning. For more information, send mail to firstname.lastname@example.org.
ATIC's Guidelines for Captioning Video
Adapted from DCMP Captioning Guidelines for Educational Media at http://www.dcmp.org/captioningkey/index.html
- Place captions on the bottom two lines of the screen as long as it does not interfere with existing visuals. If there are visuals appearing on the bottom of the screen, then place captions at the top of the screen.
- Make captions two lines or less.
- Make caption length 32 characters or less per line.
- Left-align the captions.
- Divide longer sentences at a logical point where speech normally pauses.
- Use font type Helvetica medium or similar type.
- Use a translucent box so that text will be clearer, especially on light backgrounds.
- Use sans serif characters with a drop or rim shadow, and space proportionally.
- Caption higher education media at a presentation rate of approximately 120-130 words per minute. Caption theatrical presentations at a near-verbatim rate. No caption should remain on-screen less than two seconds or exceed 235 wpm.
- Editing is performed only when a caption exceeds the presentation rate limit. Edit to maintain original meaning, content, essential vocabulary, and meet presentation rate requirements. For more details on editing, see http://www.dcmp.org/captioningkey/presentation_rate.html
- Grammatical rules for captioning punctuation, quotations and spelling are found at http://www.dcmp.org/captioningkey/lang_mechanics.html
- Special considerations for captioning sounds, speaker identification, numbers and music are listed at http://www.dcmp.org/captioningkey/special_considerations.html
- Comprehensive list of captioning tools, comments, and their tutorials by Bill Creswell.
- An excellent overview of accessibility guidelines for video
- Captioning YouTube Video and Providing Accessible Controls (from Ohio State)
- Creating Video and Multimedia Products That Are Accessible to People with Sensory Impairments
- Using accessible video and audio to enhance e-learning for disabled students
- NCAM's Free Captioning Tool: Media Access Generator (MAGpie)