confusion in 1.2.3 Audio Description or Media Alternative (Prerecorded)

Dear all,



I am going through Understanding 1.2.3 Audio Description or Media
Alternative (Prerecorded) at
https://www.w3.org/TR/UNDERSTANDING-WCAG20/media-equiv-audio-desc.html this
morning. Under the header Intent of this Success Criterion I found the
following sentence

One approach is to provide audio description of the video content. The
audio description augments the audio portion of the presentation with the
information needed when the video portion is not available.



The last wording * video portion is not available* is really confusing me.
I am in the opinion that it should be *Video portion does not convey the
important information* or similar wording.

Am I missing something here? Can someone help me understand this better.



Thanks & Regards

Rakesh Paladugula




-- 
Thanks & Regards
Rakesh Paladugula | Deque Systems Inc
Mobile: 91 9948243336| E-mail: rakesh.paladugula@deque.com
Twitter Handle: prakesh369 <http://www.twitter.com/prakesh369>
Website: Maxability.co.in <http://www.maxability.co.in>