Re: Conversion of 608/708 captions to WebVTT - how to map the colour green

On 25/02/2015 05:24, "Philip Jägenstedt" <philipj@opera.com> wrote:

>On Wed, Feb 25, 2015 at 12:16 PM, Glenn Adams <glenn@skynav.com> wrote:
>>
>> On Tue, Feb 24, 2015 at 9:36 PM, Philip Jägenstedt <philipj@opera.com>
>> wrote:
>>>
>>> On Sat, Feb 21, 2015 at 7:10 AM, Michael Borthwick
>>> <mb@michaelborthwick.com.au> wrote:
>>> > On 08/04/2014, at 1:08 PM, Silvia Pfeiffer wrote:
>>> >
>>> >> Note: I've made the change to "lime" and updated the related text,
>>>see
>>> >> https://dvcs.w3.org/hg/text-tracks/rev/07a843b7f31d

>>> >>
>>> >> Please let me know if there are more changes necessary.
>>> >>
>>> >> Regards,
>>> >> Silvia.
>>> >
>>> >
>>> > Dear list members,
>>> >
>>> > For those who are interested I have made the 22 minute video of my
>>>SMPTE
>>> > Australia 2013 talk regarding this issue available online with
>>> > appropriate
>>> > amendments to reflect the changes kindly made by Silvia last year to
>>>the
>>> > mapping of green into CSS lime.
>>> >
>>> >
>>> > 
>>>http://michaelborthwick.com.au/closed_captioning_online_streaming_video_

>>>dfxp_webvtt.html
>>>
>>> Thanks Michael, this was a great talk! I'm not sure why, but I found
>>> the trouble with green and conflicting standards very amusing, a very
>>> familiar kind of problem.
>>>
>>> Since WebVTT doesn't have any dedicated syntax for colors it really
>>> comes down to the CSS that goes along with the captions, and of course
>>> any mapping specs. Unfortunately, I suspect you will not be the last
>>> to spend time looking for a suitable green color.
>>
>>
>> Haven't had a chance to watch yet, but from TTML:
>>
>> <named-color>
>>   : ...
>>   | "green"                                 // #008000ff
>>   | "lime"                                  // #00ff00ff
>>   | "olive"                                 // #808000ff
>>
>>
>>>
>>>
>>> Did you ever hear back from the BBC about which the ultimate colors
>>> are? I doubt that #00FF00 is actually used on the Web, it's so bright!
>>
>>
>> Y = 0.299R + 0.587G + 0.114B
>
>Is this BBC green? Multiplying with 255 and rounding, that is rgb(76,
>150, 29), assuming it's the same RGB colorspace of course...

Teletext green is one of the 'full intensity' colours, in 4-bit RGB =
0,15,0. That would map to "lime" = #00ff00ff. For a reference see the
Colour Map in ETS 300 706.

Nigel



>
>In any case, it's a lot nicer than #00FF00, and a bit brighter than
>#008000.
>
>Philip
>

Received on Wednesday, 25 February 2015 15:06:52 UTC