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From: Steve Green
Date: Wed, May 27 2020 4:13AM
Subject: Unsynchronised audio and video content
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Perhaps I'm over-thinking this, but I would welcome some opinions. For the purposes of this discussion, our client is only interested in what WCAG requires, not what we think it should require, or what it was intended to require or what would be the best user experience. We are only interested in what it actually says.

There are five WCAG success criteria relating to the provision of alternatives for audio and video content, three of which only apply to synchronised media, which is defined as "audio or video synchronized with another format".

I am encountering a lot of videos that contain both audio and video, but they are not synchronised. Success criteria 1.2.2, 1.2.4 and 1.2.5 therefore do not apply, leaving only 1.2.1 and 1.2.3. Both of these require an alternative for the audio track, but as far as I can tell, WCAG only allows text alternatives for audio content in unsynchronised media, which means that captions cannot be used as an alternative.

Does anyone have an alternative interpretation of WCAG that would allow the provision of captions as an alternative for the audio content of unsynchronised media?

Regards,
Steve Green
Managing Director
Test Partners Ltd
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From: Patrick H. Lauke
Date: Wed, May 27 2020 6:01AM
Subject: Re: Unsynchronised audio and video content
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On 27/05/2020 11:13, Steve Green wrote:

> I am encountering a lot of videos that contain both audio and video, but they are not synchronised.

A file that has both audio and video together is "synchronised media",
where the audio and the video are synchronised. Or am I missing what you
mean? (I don't believe WCAG makes any more subtle distinction about
whether the audio component and video component of an a/v file need to
make sense even if they weren't in time or not here...the mere fact that
playing the video you get both the audio and the video happening at the
same time is sufficient to class that as "synchronised media").

But, assuming that what you meant is that you have pages that have both
audio-only files and video-only files. In that case, the reason why WCAG
doesn't allow captions for the audio-only files is that the assumption
here is there's no "place" for those captions to show ... i.e. if it's
an audio-only file, it would have a play/pause button, maybe a scrub
bar, but no actual large "player" area where captions would then show.
If you do somehow provide some captions (e.g. using some extra container
with automatically injected captions), then those would probably count
as a "transcript" of sorts and pass the requirement for audio-only.

P
--
Patrick H. Lauke

https://www.splintered.co.uk/ | https://github.com/patrickhlauke
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From: Steve Green
Date: Wed, May 27 2020 6:16AM
Subject: Re: Unsynchronised audio and video content
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My interpretation of WCAG's definition of "synchronised media" is that the audio and video do need to be synchronised, such as when you have a talking head i.e. the relative timing of the audio and video is important. I don't believe that merely having audio and video present at the same time is sufficient to constitute "synchronised media" if their relative timing does not matter. It would simply be "multimedia". The word "synchronised" has a very specific meaning and I don't think we can simply ignore it.

In the videos I am currently dealing with, the audio track contains all the important information. The video content is entirely decorative fluff except for a medical disclaimer that is displayed for a few seconds.

Steve

From: Patrick H. Lauke
Date: Wed, May 27 2020 6:38AM
Subject: Re: Unsynchronised audio and video content
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On 27/05/2020 13:16, Steve Green wrote:
> My interpretation of WCAG's definition of "synchronised media" is that the audio and video do need to be synchronised, such as when you have a talking head i.e. the relative timing of the audio and video is important. I don't believe that merely having audio and video present at the same time is sufficient to constitute "synchronised media" if their relative timing does not matter. It would simply be "multimedia". The word "synchronised" has a very specific meaning and I don't think we can simply ignore it.
>

https://www.w3.org/TR/WCAG21/#dfn-synchronized-media
synchronized media: audio or video synchronized with another format for
presenting information...

I'm fairly sure a video with an audio track counts as "synchronized
media", irrespective of whether the exact timing / synchronisation
between the two is important or not. I can't find any clarification
anywhere that would suggest otherwise.

See also understanding documents like
https://www.w3.org/WAI/WCAG21/Understanding/captions-prerecorded.html
https://www.w3.org/WAI/WCAG21/Understanding/audio-description-or-media-alternative-prerecorded.html
https://www.w3.org/WAI/WCAG21/Understanding/captions-live.html etc which
don't really make a specific distinction here between what does and
doesn't count as "synchronised" audio+video.

P
--
Patrick H. Lauke

https://www.splintered.co.uk/ | https://github.com/patrickhlauke
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twitter: @patrick_h_lauke | skype: patrick_h_lauke

From: Tim Harshbarger
Date: Wed, May 27 2020 6:47AM
Subject: Re: Unsynchronised audio and video content
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I would also considered them synchronized if the video and audio are part of
the same file. If they are separate and not synchronized, I think the
success criteria for video-only and audio-only media would apply.

Thanks!
Tim
Tim Harshbarger
Senior Accessibility Consultant
Deque Systems

From: Steve Green
Date: Wed, May 27 2020 6:59AM
Subject: Re: Unsynchronised audio and video content
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Without wanting to put words in their mouths, it seems that Tim and Patrick regard audio and video media as being synchronised if a single user action causes them both to either start or stop at the same time, regardless of whether their relative timing is important.

That's certainly a nice simple interpretation that is easy to apply. I really struggle to accept that logic, but I am currently outnumbered. Any other opinions one way or the other?

Steve

From: glen walker
Date: Wed, May 27 2020 12:13PM
Subject: Re: Unsynchronised audio and video content
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> In the videos I am currently dealing with, the audio track contains all
the important information. The video content is entirely decorative fluff
except for a medical disclaimer that is displayed for a few seconds.

My take is that if you can't play the audio separately from the video, then
they're synchronized. Whether the video is just fluff, if the timing of
the video plays along with the audio, it's synchronized.

From: Steve Green
Date: Wed, May 27 2020 1:18PM
Subject: Re: Unsynchronised audio and video content
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Hmm, three against one. It's starting to look as if I'm going to have to concede defeat on this one.

Steve

From: Sailesh Panchang
Date: Wed, May 27 2020 1:23PM
Subject: Re: Unsynchronised audio and video content
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>The video content is entirely decorative fluff except for a medical disclaimer that is >displayed for a few seconds.
Yes I can relate to that: like a person who is talking and the
visuals generelly cover the environment being talked about simply as a
background. The audio is not really narrating the visuals nor is in
sync with the visual and I would not regard it as synchronized media.
The exact same audio content can be ported (not my expertise) with a
background video content of a hospital / medical setting of another
location.
What is needed is the disclaimer to be portrayed on screen as text or
as a transcript. Also some short text equivalent that conveys what
setting / environment the audio is recorded in. It does not have to be
an exhaustive screen by screen portrayal of the video content. And
of course the captions or transcript for the audio content.

Timing is certainly significant for synchronized media. If the audio
and visual content are not in sync in a time-based media, then that
media would not be very usable even by non-PWD regardless of
accessibility of that media.
So a movie clip would be synchronized media where the audio content
has to be in sync with the visual content on a screen by screen
basis.
Three relevant Definitions from WCAG 2.0/2.1:
Synchronized media:
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
Alternative for time-based media
document including correctly sequenced text descriptions of time-based
visual and auditory information and providing a means for achieving
the outcomes of any time-based interaction
Note: A screenplay used to create the synchronized media content would
meet this definition only if it was corrected to accurately represent
the final synchronized media after editing.
Captions: synchronized visual and/or text alternative for both speech
and non-speech audio information needed to understand the media
content

Thanks,
Sailesh


On 5/27/20, glen walker < = EMAIL ADDRESS REMOVED = > wrote:
> > In the videos I am currently dealing with, the audio track contains all
> the important information. The video content is entirely decorative fluff
> except for a medical disclaimer that is displayed for a few seconds.
>
> My take is that if you can't play the audio separately from the video, then
> they're synchronized. Whether the video is just fluff, if the timing of
> the video plays along with the audio, it's synchronized.
> > > > >


--
Sailesh Panchang
Principal Accessibility Consultant
Deque Systems Inc
381 Elden Street, Suite 2000, Herndon, VA 20170
Mobile: 571-344-1765