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Re: Videos - do we need both captions and transcripts?

From: David MacDonald <david100@sympatico.ca>
Date: Wed, 31 May 2017 13:48:38 -0400
Message-ID: <CAAdDpDa6JGn4o1MGnFLXE1yBZbjcTeWvF3bf4yA3a133Y2eZ0Q@mail.gmail.com>
To: John Foliot <john@foliot.ca>
Cc: "Michael A. Peters" <mpeters@domblogger.net>, w3c WAI List <w3c-wai-ig@w3.org>
> audio/video -  alt is captioned and described video — or a SCRIPT containing
all dialog and sounds and all important visual information  (best for deaf
blind)

Just for clarity, the OR in the above statement applies to the described
video OR a what Gregg refers to as a SCRIPT. The captions are always
required regardless of the presence of a script.

The term we used in WCAG is "An alternative for time-based media"

https://www.w3.org/TR/WCAG20/#alt-time-based-mediadef

​I kind of wish we used SCRIPT... shorter to refer to.​


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On Mon, Feb 6, 2017 at 12:45 PM, John Foliot <john@foliot.ca> wrote:

> Michael A. Peters wrote:
> >
> > For html5 video it might be good to have examples for adding subtitles to
> > the video itself rather than just as html5 track element because videos
> are
> > often saved for stand-alone play.
> >
> > I beliebe WebVTT subtitles can be added to mkv containers (and hence
> > WebM) directly with mkvmerge, I'm not sure what has to be done to get
> > WebVTT into MP4 containers, it may need to be converted to another
> format.
>
> Hi Michael,
>
> Both MKV and MP4 file formats are "wrapper" formats that contain the
> encoded
> media (i.e. H.264 video, or AAC audio as 2 examples), and so yes, WebVTT
> files
> can be included in the MP4 wrapper as well. Post-production video tools
> usually will allow the inclusion of other content types as part of the
> export
> work-flow (for example Adobe Premier Pro). Caption, sub-title, and similar
> support files inside of those wrapper formats are usually referred to as
> "in-band", while files referenced via the track element (child element of
> Video) are referred to as "out-of-band".
>
> In addition to the "saving for off-line use" use-case, in-band support
> materials are also pretty much the only way of ensuring that they are
> delivered over lesser bandwidth conditions (i.e. Edge or 3G for mobile),
> or to
> many lower-power handhelds which lack the computing power to manage
> multiple
> discrete downloads and syncing on the client.
>
> JF
>
>
>
>
Received on Wednesday, 31 May 2017 17:49:13 UTC

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