R0037 is only about choices for a named user (such as in a browser).
Change from: The user must be able to specify the rendering of character edge types of: none, raised, depressed, uniform or drop shadowed edges.
Change to: The user should be able to specify the rendering of character edge types of: none, raised, depressed, uniform or drop shadowed edges.
Add in Future Needs (http://dvcs.w3.org/hg/ttml/raw-file/tip/ttml10-sdp-us/Overview.html#future_needs):
The character edge functions for raised, depressed and drop shadowed edges are expected to be considered for inclusion in a future version of TTML.
See Issue-191 (http://www.w3.org/AudioVideo/TT/tracker/issues/191) and Action-115 (http://www.w3.org/AudioVideo/TT/tracker/actions/115).
Thanks
Monica
Monica J Martin
Senior Program Manager
Microsoft Open Technologies, Inc.
A subsidiary of Microsoft Corporation