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Re: IMSCvNEXT + CSS styling was: TTML2 wide review comment: styling

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Sun, 1 Oct 2017 15:36:17 -0700
Message-ID: <CAHp8n2kkhkLJyN+aYpzppS13jO1XMtS7abv6qnHBpBk=ra+j2g@mail.gmail.com>
To: Pierre-Anthony Lemieux <pal@sandflow.com>
Cc: David Ronca <dronca@netflix.com>, David Singer <singer@apple.com>, Timed Text Working Group <public-tt@w3.org>
Hi Pierre, all,

With respect, in my experience, working with the CSS group to make any
missing CSS features available is more constructive than going ahead
and defining it separately.

For example, text-wrap: balance
(https://www.w3.org/TR/css-text-4/#text-wrap) is actually created to
allow WebVTT to balance the different lines in a multi-line caption
cue, which is something the caption community has asked use for. This
may well be what you are after for multiRowAlign. But even if it's
not, please work with the CSS group to make the features happen.

Kind Regards,

On Sun, Oct 1, 2017 at 3:24 PM, Pierre-Anthony Lemieux <pal@sandflow.com> wrote:
> Hi David and David et al.,
> My experience with implementing imscJS [1] has been that the mapping
> from IMSC1 to CSS was mostly straightforward and accurate, with the
> exception of two features that are not available natively in CSS but
> were deemed critical to captions: linePadding and multiRowAlign.
> [1] https://github.com/sandflow/imscJS
> In my mind, IMSCvNEXT should follow a similar pattern: mapping to
> HTML/CSS should be straightforward and accurate, with the exception of
> features that are essential to current subtitling/captioning
> practices, but not yet available in CSS. For such features, a fallback
> should be specified, and UA vendors should be encourages to support
> the feature in the future.
> Best,
> -- Pierre
> On Sat, Sep 30, 2017 at 6:01 PM, David Ronca <dronca@netflix.com> wrote:
>>> Please consider adopting CSS as-is, without embellishment or improvement.
>> CSS is beyond the scope of TTML2, and would be a requirement for TTMLvNext.
>> Once of the deliverables for IMSCvNext will be a node.js  TTML->CSS
>> transform implementation that will preserve as much of the TTML styling as
>> possible.  This will simplify IMSCvNext rendering for HTML clients.
>> On Sat, Sep 30, 2017 at 5:49 PM, David Singer <singer@apple.com> wrote:
>>> The styling model used in TTML2 is not CSS and is not processable by a
>>> processor/rendering-engine designed to support HTML/CSS.  This leads to
>>> complex ‘come from’ process deep in rendering engines, where the behavior
>>> has to be dependent on whether the text ‘came from’ an HTML/CSS context or a
>>> TTML context.
>>> Please consider adopting CSS as-is, without embellishment or improvement.
>>> David Singer
>>> Manager, Software Standards, Apple Inc.
Received on Sunday, 1 October 2017 22:37:03 UTC

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