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Re: ISSUE-309 (Image profile fails WCAG 1.2): Image profile needs to permit text equivalent [TTML IMSC 1.0]

From: Nigel Megitt <nigel.megitt@bbc.co.uk>
Date: Thu, 22 May 2014 09:23:41 +0000
To: Michael Dolan <mdolan@newtbt.com>, "'Timed Text Working Group'" <public-tt@w3.org>
Message-ID: <CFA3724F.1E19E%nigel.megitt@bbc.co.uk>
Let's stick to the problem at hand – we're not working on CFF but on IMSC. If W3C is to make a recommendation that doesn't meet its own accessibility guidelines there has to be some explanation or context to describe how the impact on the user is mitigated. If there's work from CFF that you can bring in to back this up please do share it.

In terms of stand-along TTML documents, there's currently no hard requirement in IMSC that conformant documents are not standalone, so we have to cover the requirements when they are standalone.

However, Mike, you've clearly said you don't object to enabling text in the image profile. If there are no other objections then we can simply resolve to do that and close the issue with a decision to implement the change.


On 21/05/2014 20:01, "Michael Dolan" <mdolan@newtbt.com<mailto:mdolan@newtbt.com>> wrote:

“Overlooked” and a “pity” in W3C perhaps, but not in CFF where it was studied and rejected as it created more problems than it solved.  Alternative full tracks/documents are a much cleaner solution in full media files (e.g. MP4).

Maybe W3C has different requirements for stand-alone TTML documents?

No objection to enabling it, but we could do with less judgment about other industry work.


From: John Birch [mailto:John.Birch@screensystems.tv]
Sent: Wednesday, May 21, 2014 2:02 AM
To: Timed Text Working Group
Cc: Glenn Adams
Subject: RE: ISSUE-309 (Image profile fails WCAG 1.2): Image profile needs to permit text equivalent [TTML IMSC 1.0]

This is actually a very old ‘requirement’… (it’s a great pity it is consistently over-looked ☹

http://www.w3.org/2005/03/21/DFXPLastCallResponses.html - specifically Al Gilman’s comments


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From: Glenn Adams [mailto:glenn@skynav.com]
Sent: 21 May 2014 09:41
To: Timed Text Working Group
Subject: Re: ISSUE-309 (Image profile fails WCAG 1.2): Image profile needs to permit text equivalent [TTML IMSC 1.0]

I had previously reported this same comment on the CFF-TT image profile.

On Wed, May 21, 2014 at 5:32 PM, Timed Text Working Group Issue Tracker <sysbot+tracker@w3.org<mailto:sysbot+tracker@w3.org>> wrote:
ISSUE-309 (Image profile fails WCAG 1.2): Image profile needs to permit text equivalent [TTML IMSC 1.0]


Raised by: Nigel Megitt
On product: TTML IMSC 1.0

IMSC1 Image profile [1] defined in §6 does not permit a text equivalent. If this profile is used to provide captions as an alternative to audio then it will fail the WCAG2 guideline 1.2 [2]. From a practical perspective this would mean that users who can neither see nor hear well can not use tools to translate the content into e.g. Braille.

[1] http://www.w3.org/TR/ttml-imsc1/#image-profile-constraints

[2] http://www.w3.org/TR/2008/REC-WCAG20-20081211/#media-equiv

Some potential ways to solve this:
1. Permit text to be included within the image profile that describes the images.
2. Require or recommend that when image profile captions are provided there should be a text profile caption track available simultaneously.

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Received on Thursday, 22 May 2014 09:24:13 UTC

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