TTML2 and Japanese features

Dear Timed Text experts,

Please find attached a white paper that we have written at Netflix. This
document is a technical description of the work that we have done to
support Japanese subtitles, intended for discussion at TPAC. The primary
purpose of the document is to describe the features that we consider
essential for the success of IMSC1.1, and how TTML2 tools are used by
Netflix to enable those features.

Looking forward to your comments,
Cyril