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Re: HTML 5, SMIL, Video

From: Geoff Freed <geoff_freed@wgbh.org>
Date: Sat, 20 Feb 2010 07:19:20 -0500
To: Dick Bulterman <Dick.Bulterman@cwi.nl>, Silvia Pfeiffer <silviapfeiffer1@gmail.com>
CC: John Foliot <jfoliot@stanford.edu>, "public-html-a11y@w3.org" <public-html-a11y@w3.org>, "markku.hakkinen@gmail.com" <markku.hakkinen@gmail.com>, "symm@w3.org" <symm@w3.org>
Message-ID: <C7A53D78.A322%geoff_freed@wgbh.org>

On 2/20/10 3:27 AM, "Dick Bulterman" <Dick.Bulterman@cwi.nl> wrote:

Hi Silvia,

Responding to your recent comments:

> Is there
> anything that smilText does that is above what DFXP does?

Sure:
a) it can be used as an in-line and external formal out of the box
b) it is steamable
c) it uses a significantly simpler syntax
d) it allows a mix of absolute and relative timing
e) it provide primitives for text motion (crawling, rolling, etc)
f) it has supports conventional HTML structuring and styling
    primitives

Other than that, it was designed to be largely compatible with the
semantis of DFXP so that the breadth of DXFP could be used when
appropriate. In many ways, our thoughts were the same as yours: the
issue in not DFXP or smilText, but DFXP AND smilText. I think that the
same is true for this group.

> I don't see any advantage of this markup:
> <smilText dur="6s">
>       Hello<br/>world!
>       <tev next="2s"/>
>       How are you today?
>       <clear begin="4s"/>
>       I gotta go now!
> </smilText>
>
> over this markup:
> 1
> 00:00:00,000 --> 00:00:04,000
> Hello world!
>
> 2
> 00:00:02,000 --> 00:00:04,000
> How are you today?
>
> 3
> 00:00:4,000 --> 00:00:06,000
> I gotta go now!
>
> If anything, the SRT markup is more readable.

Here is my summary of the advantages in this example for smilText
a) it is an XML format
b) it can be plugged directly into HTML with no new syntax
c) it has an architecture that allows structuring, styling, motion and
other forms of manipulation (roles, etc) to be added easily
d) it is less dense than SRT (in this example, more than 10%)
e) it is less prone to error in hand-editing
f) because the ordering of content can be realive, the contents can
be generated on-the-fly, with inserts possible
g) the 'begin' attribute can also be used for event-based scheduling
of text objects; since these also can have ID's, it can also hurl events
to an outside context -- this has the nice ability for users to control
the flow and tempo of content delivery. (A longer term benefit.)

It has also already gone thru W3C standardization (there is a test
suites, there have been multiple implementation tests, it has passed the
entire process), but I don't think that you consider this important.

In short: everything that you need to add to SRT to make it useful is
already in smilText. And everything that SRT can do (and much more) can
be done by smilText.

Of course, these are only advantages if you want them to be. You can
always come up with a stream of arguments why extensibility is not
important because nobody uses it now, why XML is not important, why
whatever is not important. If I look at the a11y needs, coupled with the
needs to support generalized incidential timed text within a document,
then the choice is not very difficult: I'd go for a mix of smilText and
DFXP.

I'd be interested to hear what others think on this issue.
(If everyone's mind is already made up -- which is sort of the
impression that I get -- then it is a shame to waste our collective time
on this.)

GF:  Dick makes a good case for both formats.  For all the reason's I've stated previously, I'd be fine with that.


-d/

(Since joining the a11y list is not a trivial process, I'd one again
appreciate it if someone would foward this message -- thanks!)
Received on Saturday, 20 February 2010 12:20:07 GMT

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