Understanding Captioning Requirements

Captions are mandated primarily for deaf and hard-of-hearing viewers, but captions can be a benefit in these instances:

  • For non-native speakers;
  • When vocabulary or dialect is unfamiliar; and
  • When audio is not clear or is unavailable.

In some cases, up to 80% of viewers using captions are not considered deaf or hard of hearing, including instances when a person cannot listen to audio because of their work or study environment.

Video player

The video player should allow users to:

  • Control the video (e.g. pause, rewind, etc.) via the keyboard only*;
  • Control the volume with the keyboard only*;
  • Control when the video begins (ideal), or if it begins automatically, provide the viewer a mechanism to pause the video at the beginning of the page;
  • Turn on captions or audio descriptions with the mouse only; and
  • Turn on captions or audio descriptions with the keyboard only.

*All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes, except where the underlying function requires input that depends on the path of the user's movement and not just the endpoints. This does not forbid and should not discourage providing mouse input or other input methods in addition to keyboard operation.


Video captions should:

  • Appear at the same time as the sound they are captioning;
  • Ensure all important audio information has been captured;
  • Appear on the screen for enough time for them to be read;
  • Ensure the contrast between background and caption text color is sufficient;
  • Have no periods without captions; and
  • Attribute speech to a particular speaker.

See "DCMP Closed Captioning Standards" (3Play Media) for recommendations and guidelines.


Video transcripts should:

  • Identify the name of the speaker;
  • Ensure that all speech content is included;
  • Include relevant information about the speech;
  • Include relevant non-speech audio;
  • Include any textual or graphical information shown in the video;
  • Be provided in an accessible format;
  • Indicate the end of the transcript if on the same page as the video; and
  • Provide a mechanism to return to the video if on another page.

Did you know?

  • In the United States, about 55 million people have a disability (src: 2010 U.S. Census).
  • About 1 in 5 Americans have some kind of disability (src: 2010 U.S. Census).
  • The percentage of people affected by disabilities is growing as our population ages.
  • Two popular, free screen readers are VoiceOver (Mac OS and iOS) and NVDA (Win).
  • Good accessibility practices can improve the search ranking of your website.
  • Form fields without labels can cause problems for some assistive technology users.
  • Low color contrast makes content difficult to see, especially for users with low vision.
  • Documents linked on a website need to be accessible too (e.g., PDF and Word files).
  • Audio content, like podcasts, need transcripts for deaf or hard of hearing users.
  • Online videos should be captioned for deaf or hard of hearing users.
  • Using HTML tags correctly is very important for accessibility.
  • Descriptive link text helps make a website more accessible. Avoid using "Click here" or "Read more."
  • A "screen reader" is an application that reads content aloud to a user.
  • There is no "alt tag" in HTML. "Alt" is an attribute used with the img tag.
  • HTML uses the alt attribute to provide a text description of an image.
  • Alt text should describe an image, if the purpose of the image is to convey information.
  • If an image is a link, the alt text for the image should explain where the link goes.
  • If an image is only being used for decoration, the alt text should be null (i.e., alt="").
  • If a table has headers, using header tags (<th>) will make the table more accessible.
  • An accessible website is one that can be navigated and understood by everyone.