RE: Meaning of "synchronized media"

Robin,
The short answer would be providing captioning for hearing impaired where audio is supplied and textual description of information provided in video format for visually impaired.

From: Robin Hillman [mailto:robinhillman@tactica.ca]
Sent: Friday, February 5, 2016 9:14 AM
To: w3c-wai-ig@w3.org
Subject: Meaning of "synchronized media"

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: https://www.w3.org/TR/UNDERSTANDING-WCAG20/media-equiv-audio-desc-only.html


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?

Thanks!
-Robin Hillman