[imsc] Replay liaison from ARIB to W3C TTWG (Re: W3C TTWG liaison to ARIB requesting review of IMSC 1.0.1)

Dear Mr. Nigel Megitt,
Chair, W3C Timed Text Working Group

ARIB would like to thank the W3C Timed Text Working Group to inform us
of your latest development of IMSC Recommendation. As the result of
reviewing the working draft of IMSC-1.0.1 and exchanging opinions with
IPTV Forum Japan, following comments are offered.

- It is understood that the purpose of the activeArea attribute is to
specify an area where nothing disturbs presentation of an element with
this attribute. However, it is unclear for us how to do it because
behavioral model of this attribute is not defined. The draft notes the
case in which video cropping involves cropping of captions. But
considering a case that the other object(s) are trying to overlap the
object with this attribute, a relation between the attribute and z-index
of CSS should come to an issue.

- The fillLineGap attribute is intended to widen background color
filling of letters to line gap. Fig.1 of the draft looks filling the 
background in a color of descent in the upper line to the center of 
leading, and the other half of leading is filled in a color of ascent 
in the next line. We are not sure this is the typical case for 
determination of the color in leading. It is suggested to describe 
color determination algorithm, or to describe it is 
implementation-dependent.

If you have any questions to our comments, please feel free to contact
us. We would like to keep in touch with you on the topics

Sincerely,
Shinya TAKEUCHI
Chair, ARIB Data Coding Technology working group


----- Original Message -----
> To: Shinya Takeuchi, ARIB, W3C Timed Text Liaison contact
> 
> 
> Dear Shinya Takeuchi,
> 
> The W3C Timed Text Working Group has recently published a new working 
draft of the TTML Text and Image Profiles for Internet Media Subtitles 
and Captions 1.0.1, currently known as IMSC 1.0.1 [1]; note that the 
version number may be subject to change before final publication as a 
Recommendation. This specification contains two optional features 
additional to the IMSC 1 Recommendation [2]:
> 
>   1.  activeArea allows the document author to indicate which area 
contains active editorial content in the presentation.
>   2.  fillLineGap allows the document author to specify that the 
background areas of adjacent lines meet without an intervening gap.
> 
> The TTWG invites you to review this draft, and requests comments to be 
received by 7th May 2017. These comments will be used to fulfil the W3C 
Process [3] requirement for Wide Review of drafts prior to publication 
as Candidate Recommendation.
> 
> If you wish to make comments regarding this document, please send them 
to <mailto:public-tt@w3.org> public-tt@w3.org<mailto:public-tt@w3.org?
subject=[imsc]> with [imsc] at the start of your email's subject. All 
comments are welcome, however the scope of review will be focused on the 
two new features described above.
> 
> [1] IMSC 1.0.1 latest version https://www.w3.org/TR/ttml-imsc1.0.1/
> [2] IMSC 1 Recommendation https://www.w3.org/TR/ttml-imsc1/
> [3] W3C Process https://www.w3.org/2017/Process-20170301/
> 
> Kind regards,
> 
> Nigel Megitt, co-Chair, W3C Timed Text Working Group
> 
>

Received on Friday, 5 May 2017 17:25:40 UTC