Re: Meaning of "synchronized media"

Synchronized media refers to the situation where there are multiple media types that are shown in a time-dependent manner.

An audio file on a web page is not synchronized media, and nor is a video file that doesn’t have audio. But if you play these together and the timing of one depends on the other in order to understand the content, then these are “synchronized media”.  Similarly, if you had an audio file and a synchronized sequence of images that appears at the same time, that would constitute synchronized media.  In many cases like this last example, the image sequence might be converted into a proper video file format, probably including the audio in that file as well, but this doesn’t have to happen. The term synchronized media establishes that the success criteria aren’t just referring to video with audio needing captions and audio descriptions, there are other cases where these are needed to provide access.


Andrew Kirkpatrick
Group Product Manager, Accessibility

From: Robin Hillman <<>>
Date: Friday, February 5, 2016 at 09:14
To: "<>" <<>>
Subject: Meaning of "synchronized media"
Resent-From: <<>>
Resent-Date: Friday, February 5, 2016 at 09:14

Hello --
I have a question about the meaning of "synchronized media", because the terms used seem very specific. This is related to SC 1.2.5 in WCAG 2.0:

It defines synchronized media as:
"audio or video synchronized with another format for presenting information and/or with time-based interactive components, unless the media is a media alternative for text that is clearly labeled as such"

My confusion is around "audio or video synchronized with another format" -- what is "another format"? What would some examples of synchronized media be? Does this necessarily include something like a movie?

So does this mean that all videos (I mean, audio & video, like what you would see on youtube) would require described audio in order to meet this SC?

-Robin Hillman

Received on Friday, 5 February 2016 14:43:05 UTC