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Re: [WebVTT] It's not easy being green

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Wed, 18 Mar 2015 07:12:39 +1100
Message-ID: <CAHp8n2m1Xyu1Mj9zhsEsGkecfA6nqt_uA_4dMXr73ekAF=CAVg@mail.gmail.com>
To: Pierre-Anthony Lemieux <pal@sandflow.com>
Cc: Public TTWG List <public-tt@w3.org>, Michael Dolan <mdolan@newtbt.com>, David Singer <singer@apple.com>
I've just posted a summary of what took place there for WebVTT for the
advantage of this list.

I don't know about the situation of TTML specs, so that discussion should
probably still be had.

Best Regards,
Silvia.
On 18 Mar 2015 07:03, "Pierre-Anthony Lemieux" <pal@sandflow.com> wrote:

> > I think we already discussed this…
>
> The discussion took place on the CG list, and not on the WG list,
> unless I am mistaken.
>
> Best,
>
> -- Pierre
>
> On Tue, Mar 17, 2015 at 12:11 PM, David Singer <singer@apple.com> wrote:
> > I think we already discussed this…
> >
> > see thread starting <
> https://lists.w3.org/Archives/Public/public-texttracks/2014Mar/0031.html>
> >
> >> On Mar 16, 2015, at 17:03 , Michael Dolan <mdolan@newtbt.com> wrote:
> >>
> >> I received an email from someone studying SMPTE-TT and WebVTT who wrote
> and presented a paper about 18 months ago titled, “'It's not easy being
> green - a closed captioning for web case study'”.  Among other things, he
> observed that we map CEA 608 “green” to SVG/CSS3 “green”.
> >>
> >> FYI, the SVG/CSS3 RGB value of “green” is 008000, not 00FF00 you might
> expect (which is the color “lime”):
> >> http://www.w3.org/TR/css3-color/#html4
> >> Note in contrast that “red” and “blue” are both full brightness.
> >>
> >> Of the various 608 mapping documents….SDP-US uses only RGB values (no
> color names) and explicitly defines “green” to be 00FF00.  However both
> SMPTE-TT (RP2052-10) and WebVTT say to map 608 “green” to TTML “green”
> which is minimally inconsistent with SDP-US. The same would be true for 708
> mappings, of course.
> >>
> >> Of historical note, CSS1 says the color palette came from the “Windows
> VGA palette”, which seems to have come from the CGA text color palette:
> >> http://en.wikipedia.org/wiki/Color_Graphics_Adapter
> >> (although the above  defines the brighter green as “light green”).
> >>
> >> We could assume it is supposed to be maximum brightness like “red” and
> “blue” (i.e. 00FF00), but on the off chance that “green” text overlay is
> actually handled differently in the billion TV’s out there I’ll ask a
> couple of set manufacturers….
> >>
> >> Regards,
> >>
> >>                 Mike
> >>
> >> -------------------------
> >> Michael A DOLAN
> >> TBT, Inc. PO Box 190
> >> Del Mar, CA 92014
> >> (m) +1-858-882-7497
> >
> > David Singer
> > Manager, Software Standards, Apple Inc.
> >
> >
>
>
Received on Tuesday, 17 March 2015 20:13:06 UTC

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