[w3ctag/design-reviews] Review of IMSC-HRM (Issue #788)

Wotcher TAG!

I'm requesting a 

# TAG review of IMSC-HRM

## What it is

The [IMSC Hypothetical Render Model (HRM)](https://www.w3.org/TR/imsc-hrm/) constrains the presentation processing complexity of subtitle and caption documents that conform to the [IMSC Recommendation](https://www.w3.org/TR/ttml-imsc/).

The HRM is not a new concept: it has been included in all versions and editions of the IMSC [Recommendation](https://www.w3.org/TR/ttml-imsc/) and has remained substantially unchanged.

In order to simplify future maintenance, the TTWG wishes to refactor the HRM into its own Recommendation.

## Key info

  - Explainer¹ (minimally containing user needs and example code): https://github.com/w3c/imsc-hrm/blob/main/misc/explainer.md

  - Specification URL: https://www.w3.org/TR/imsc-hrm/

  - Tests: will be located at https://github.com/w3c/imsc-hrm-tests when they have been created
  - User research: none specific to the IMSC-HRM
  - Security and Privacy self-review²: https://github.com/w3c/imsc-hrm/blob/main/misc/security-and-privacy.md (currently visible via w3c/imsc-hrm#57)
  - GitHub repo (if you prefer feedback filed there): https://github.com/w3c/imsc-hrm/

  - Primary contacts (and their relationship to the specification):
      - Nigel Megitt (@nigelmegitt), BBC (Chair, TTWG)
      - Pierre-Anthony Lemieux (@palemieux), Movielabs (Editor, IMSC-HRM)
      - Gary Katsevman (@gkatsev), Mux (Chair, TTWG)
  - Organization(s)/project(s) driving the specification: W3C TTWG
  - Key pieces of existing multi-stakeholder review or discussion of this specification: This specification has been published in IMSC Recommendations and has therefore gone through Wide Review and TAG review previously as part of those IMSC Recommendations. Usage of the IMSC-HRM to analyse real world subtitle and captions documents from a variety of sources has led to issues such as w3c/imsc-hrm#49.
  - External status/issue trackers for this specification (publicly visible, e.g. Chrome Status): None that we're aware of

## Further details:

  - [X] I have reviewed the TAG's [Web Platform Design Principles](https://www.w3.org/TR/design-principles/)
  - Relevant time constraints or deadlines: We would like to transition from WD to CR in the next 2-3 months if possible
  - The group where the work on this specification is currently being done: W3C TTWG
  - The group where standardization of this work is intended to be done (if current group is a community group or other incubation venue): same, W3C TTWG
  - Major unresolved issues with or opposition to this specification: None. 
  - This work is being funded by: TTWG members

## Also

You should also know that...

One question we are considering is whether we should update existing IMSC Recommendations to remove the existing HRM text and then either to 1) normatively reference IMSC-HRM as a conformance requirement or 2) informatively reference the IMSC-HRM as an optional conformance requirement for users to decide on. 

The goal of the IMSC-HRM is to set a maximum presentation complexity for subtitle and caption documents to maximise the likelihood that presentation processors will successfully produce an accessible experience for end users, in particular timely presentation. It is out of scope for IMSC-HRM to model or constrain readability complexity.

## Feedback

We'd prefer the TAG provide feedback as:

  🐛 open issues in our GitHub repo for **each point of feedback**



-- 
Reply to this email directly or view it on GitHub:
https://github.com/w3ctag/design-reviews/issues/788

You are receiving this because you are subscribed to this thread.

Message ID: <w3ctag/design-reviews/issues/788@github.com>