What is Time-based media?

Question

I see that one of the web accessibility guidelines is 'Time-based Media'. What is that?

Answer

Time-based media is content that must be made accessible when held against criterion 1.2 of the WCAG 2.0 guidelines found here: https://www.w3.org/TR/UNDERSTANDING-WCAG20/media-equiv.html Content is considered time-based media if it's:
  • Audio-only
  • Video-only
  • A combination audio/video
  • Audio and or video combined with an interaction.
This terminology encompasses a broad number of third-party software platforms and content libraries, such as:
  • YouTube
  • Video.js
  • SoundCloud
  • Spotify
Put broadly, time-based media is anything that's embedded on a website that: moves, makes noise, displays content synchronized with another element of the site, or displays content that changes without user input. Certain accessibility considerations need to be made when building content so that everyone has access to content regardless of their level of ability.