FYI: [transition] REC Request for IMSC 1.3 - IMSC Text Profile 1.3

This may be of interest for some of us…

> This specification defines a text-only profile of [ttml2 <https://www.w3.org/TR/ttml-imsc1.3/#bib-ttml2>] intended for subtitle and caption delivery applications worldwide.
> It improves over the Text Profile specified at at [ttml-imsc1.2 <https://www.w3.org/TR/ttml-imsc1.3/#bib-ttml-imsc1.2>], with the improvements summarized at L. Summary of substantive changes <https://www.w3.org/TR/ttml-imsc1.3/#substantive-changes-summary>.

- https://www.w3.org/TR/ttml-imsc1.3/

Ivan

> Begin forwarded message:
> 
> From: noreply@w3.org
> Subject: [transition] REC Request for IMSC 1.3 - IMSC Text Profile 1.3
> Date: 30 March 2026 at 08:46:44 GMT+2
> To: public-transition-announce@w3.org
> Resent-From: chairs@w3.org
> Reply-To: public-transition-announce@w3.org
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> 
> REC Request for IMSC 1.3 - IMSC Text Profile 1.3
> from https://github.com/w3c/transitions/issues/788
> 
> # Document title, URLs, estimated publication date
> https://www.w3.org/TR/ttml-imsc1.3/
> IMSC Text Profile 1.3
> no estimation, as soon as following AC review and else
> 
> # Abstract
> https://www.w3.org/TR/ttml-imsc1.3/#abstract
> 
> # Status
> https://www.w3.org/TR/ttml-imsc1.3/#sotd
> 
> # Will new features be allowed to be incorporated in the Recommendation?
> [no](https://github.com/w3c/imsc/blob/c8fa54f64dbd426bd950c4e33128bce11e0243e2/imsc1/spec/ttml-ww-profiles.html#L231)
> 
> # Link to group's decision to request transition
> https://lists.w3.org/Archives/Public/public-tt/2026Mar/0006.html ([CfC](https://lists.w3.org/Archives/Public/public-tt/2026Feb/0020.html) and [meeting minutes to CfC](https://www.w3.org/2026/02/26-tt-minutes.html#204e))
> 
> # Changes
> https://www.w3.org/TR/ttml-imsc1.3/#substantive-changes-summary
> 
> # Requirements satisfied
> Yes (as minor updated from [IMSC 1.2 REC](https://www.w3.org/TR/2020/REC-ttml-imsc1.2-20200804/) with one new TTML feature enabled)
> 
> # Dependencies met (or not)
> yes
> 
> # Wide Review
> * [wide review tracker for 1st CRS](https://github.com/w3c/imsc/issues/608)
>  * a11y https://github.com/w3c/a11y-request/issues/116 ([one needs resolution](https://github.com/w3c/imsc/issues/626) filed and [agreed with change by joint call](https://github.com/w3c/a11y-tracking/issues/252#issuecomment-4113292301))
>  * TAG https://github.com/w3ctag/design-reviews/issues/1122
>  * i18n https://github.com/w3c/i18n-request/issues/268
>  * privacy https://github.com/w3cping/privacy-request/issues/167
>  * security https://github.com/w3c/security-request/issues/95
> * from [1st CRS](https://www.w3.org/TR/2025/CR-ttml-imsc1.3-20251218/), several CRD [published](https://www.w3.org/standards/history/ttml-imsc1.3/) with informative changes ([diff](https://services.w3.org/htmldiff?doc1=https%3A%2F%2Fwww.w3.org%2FTR%2F2025%2FCR-ttml-imsc1.3-20251218%2F&doc2=https%3A%2F%2Fwww.w3.org%2FTR%2F2026%2FCRD-ttml-imsc1.3-20260226%2F), [merged PRs after CRS publication 2025-12-18](https://github.com/w3c/imsc/pulls?q=is%3Apr+is%3Aclosed+sort%3Aupdated-desc+merged%3A%3E2025-12-18))
>  * editorial (metadata, respec syntax) https://github.com/w3c/imsc/pull/630, https://github.com/w3c/imsc/pull/629, https://github.com/w3c/imsc/pull/627, https://github.com/w3c/imsc/pull/623, https://github.com/w3c/imsc/pull/631
>  * added informative note for a11y-needs-resolution https://github.com/w3c/imsc/pull/628, https://github.com/w3c/imsc/pull/637
>  * updated [informative overview](https://www.w3.org/TR/2026/CRD-ttml-imsc1.3-20260226/#introduction) and [sample IMSC document](https://www.w3.org/TR/2026/CRD-ttml-imsc1.3-20260226/#sample-instance https://github.com/w3c/imsc/pull/632/
>  * alphabetically reorder items (by subsection heading) in [8. Additional Provisions](https://www.w3.org/TR/2026/CRD-ttml-imsc1.3-20260226/#common-constraints) https://github.com/w3c/imsc/pull/636
>  * improved ja entry of Table 2. Supplementary Character Sets in [Appendix B. Common Character Sets](https://www.w3.org/TR/2026/CRD-ttml-imsc1.3-20260226/#recommended-unicode-code-points-per-language) https://github.com/w3c/imsc/pull/614 ([definition does not intend to limit the set of characters that a Processor renders](https://www.w3.org/TR/2026/CRD-ttml-imsc1.3-20260226/#h-note-50))
> 
> # Issues addressed
> [closed issue labelled as imsc1.3 and closed after previous REC (IMSC 1.2) publication](https://github.com/w3c/imsc/issues?q=is%3Aissue%20state%3Aclosed%20closed%3A%3E2020-08-04%20label%3Aimsc1.3)
> 
> # Formal Objections
> no objections during specification development
> 
> # Implementation
> https://www.w3.org/wiki/TimedText/IMSC1_3_Implementation_Report
> 
> # Patent disclosures
> https://www.w3.org/groups/wg/timed-text/ipr/#current-disclosures
> 
> NOTE: For more information, see [Organize a Technical Report Transition](https://www.w3.org/Guide/transitions?profile=newREC).
> 
> /cc @w3c/w3c-group-34314-chairs @palemieux
> 
> 
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> This email was generated automatically using https://github.com/w3c/transition-issues-bot
> 


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Ivan Herman, W3C 
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