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Re: In-file style sheets for VTT, discussion

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Wed, 11 Mar 2015 22:09:03 +1100
Message-ID: <CAHp8n2=Tex-QL_RZembBu7S7vi03xOSnGGRwaKCLu4XKotyHvw@mail.gmail.com>
To: Thierry MICHEL <tmichel@w3.org>
Cc: Public TTWG List <public-tt@w3.org>, "public-texttracks@w3.org" <public-texttracks@w3.org>, David Singer <singer@apple.com>
On Wed, Mar 11, 2015 at 9:41 PM, Thierry MICHEL <tmichel@w3.org> wrote:
>
>
> On 11/03/2015 09:47, Silvia Pfeiffer wrote:
>>
>>
>> On 11 Mar 2015 18:31, "Thierry MICHEL" <tmichel@w3.org
>> <mailto:tmichel@w3.org>> wrote:
>
>
>>  > To allow this, adding CSS styling within WebVTT file would satisfy
>> that need. Web browsers could also parse WebVTT file styling.
>>  >
>>
>> Yes, that's a good summary of the motivation for this feature.
>>
>>  > Also providing a CSS styling within WebVTT file resolves some
>> accessibilities issues, if the users needs to change the default styling
>> (bigger fonts, diffrent colors, etc...)
>>  >
>>
>> Not really, because such styling would be supplied power user through
>> browser settings so they would overrule CSS styling.
>
>
> Yes I agree that browser settings would work in an HTML browser Player. But
> that does not work in a non HTML Media Player.


Wouldn't a media player also have default settings specific for the
user? This styling is for the author to provide, so I don't see how
that can satisfy all the different accessibility use cases.


> The issue is do we want to have a text track format that only palys in Web
> Browsers, or do we want also to adress playing WebVTT files in regular Media
> player.
>
> Currently SRT can be played in regular Media player. I would hope that
> WebVTT does the same with its improved capabilities.

Agreed.

>>
>>  > CSS stylings in the WebVTT file can be done as follows:
>>  >
>>  > 1-In the Header:
>>  >
>>  > 1.1- Import a CSS style sheet:
>>  >     Style:
>>  >       @import(cea608.css)
>>  >     ##
>>  >
>>  > 1.2- In a  CSS style declaration section:
>>  >     WEBVTT
>>  >       Style:
>>  >       ::cue(v[voice=Bob]) {color:green;}
>>  >       ::cue(c.question) {font-style:italic;}
>>  >     ##
>>  >
>>
>> There's a bit more detail in the bug that David referenced. Again: if
>> there are technical concerns, I would encourage discussion to continue
>> in the bug, so it status together as much as possible.
>
>
> Yes I know it is recorded in the bug tracker, but maybe the TTWG wants also
> to discuss this.

I would absolutely encourage this. We just don't want to have repeat
technical arguments. The bug tracker is accessible to everybody, so
should not restrict anyone in the TTWG from contributing there.


>>  > 2- Inline styling (throughout the WebVTT file not just in the header
>> of a WebVTT file). Possibly even scoped for individual cues -
>>
>> This use case was rejected by Apple, so as to avoid having to keep track
>> of such temporary changes during the duration of the video and enable
>> direct access ability, in particular in in-band or hls used of WebVTT.
>
>
> OK, I also agree that this feature isn't a must.
>>
>>
>> I think that's fair, since we have this:
>>
>>  > Note: Currently there is support per-cue styling via cue IDs (but not
>> yet implemented).
>>  >     <style>  ::cue(#myid) {font-style : italic;}  </style>
>>
>> It's implemented in chrome and safari, just not in Firefox or IE.
>
>
>
> Wel I tried it on Chrome Version 38.0.2125.111 m
> The following code does not work
> in the HTML page:
>  ::cue(#c11)       {color:yellow;}
>
> in the WebVTT file:
> c11
> 00:00:51.000 --> 00:00:55.000
> This cue has a unique id.
> Using CSS, its font color should be yellow.
>
> I also tried it on Safari on my Ipad, does not work either.
>
> You can try it with my demo online
> https://www.w3.org/2015/Talks/0212-WebVTT/#(25)

I think you might be right. Here's another test of this:
http://www.jwplayer.com/html5/webvtt/ .
It seems that ::cue works, but not for addressing cues by ID.
It's possible to do this via classes though.

Cheers,
Silvia.

>
> But maybe I am missing something ...
>
> Cheers,
> Thierry
>
>
Received on Wednesday, 11 March 2015 11:09:50 UTC

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