IMSC Hypothetical Render Model

Hi all,

I reviewed "IMSC Hypothetical Render Model" working draft at

I have this question for the authors--please review and if we agree, I will
-- I need some guidance as to where to post my comment--

- Lionel

It is clear to APA that this specification relates to subtitles rendering.
Captions and other such synchronized streaming text is critical to many
accessible user experiences, and indeed WCAG is references explicitly in
the referenced specifications TTML and TTML Profiles.

Our question is: if the IMSC Hypothetical render model decides that
complexity exceeds the capability of the system to render, and returns an
error message, does this impact the accessibility of the system? Or are
such error states already handled in the parent specifications, and this
document is only a low level API without any impact on the experience of

Lionel Wolberger
COO, UserWay Inc. <>

Received on Friday, 10 December 2021 16:57:19 UTC