Audio description requirements question

I have a question regarding the audio description requirements for
pre-recorded video that I am hoping to seek clarity on.



1.    WCAG 2 1.2.3 requires audio description or media descriptions for
Level A

2.    WCAG 2 1.2.5 requires audio description Level AA and indicates that
audio description should be provided within the pauses of the multimedia.

3.    WCAG 2 1.2.7 requires extended audio descriptions for multimedia
where there is not sufficient pauses – Level AAA –  guidance documents also
indicate media description



If a multimedia presentation does not have sufficient pauses to allow for
audio description, does it still meet Level AA if a media description is
provided?  The non-normative guidance in SC 1.2.7
http://www.w3.org/TR/UNDERSTANDING-WCAG20/media-equiv-extended-ad.htmlseems
indicates
that 1.2.7 only applies to when audio description can be inserted in the
pauses.



Additionally, and somewhat related, guidance from SC 1.2.5 in the
non-normative document at
http://www.w3.org/TR/UNDERSTANDING-WCAG20/media-equiv-audio-desc-only.htmlindicates
that if audio description and a media alternative are provided
then extended audio description is not needed for Level AAA as it is
already met by providing both of these.



Ø   This is an additional requirement if both 1.2.3 and 1.2.5 were met by
providing an audio description only. If 1.2.3 was met, however, by
providing a text description, and the 1.2.5 requirement for an audio
description was met, then 1.2.8 does not add new requirements.



Best Regards,



Jonathan