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Re: In-file style sheets for VTT, discussion

From: Thierry MICHEL <tmichel@w3.org>
Date: Wed, 11 Mar 2015 13:46:12 +0100
Message-ID: <55003914.6010603@w3.org>
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
CC: Public TTWG List <public-tt@w3.org>, "public-texttracks@w3.org" <public-texttracks@w3.org>, David Singer <singer@apple.com>


On 11/03/2015 12:09, Silvia Pfeiffer wrote:
> 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.

OK.

>>>   > 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
>>
>> 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.

Yes cues by classes work in Chrome.
But cues by ID, as specified in the WebVTT spec, currently don't work in 
any browser I am aware of.
Received on Wednesday, 11 March 2015 12:46:16 UTC

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