[ttml2] Pull Request: Add @ttm:alt as shorthand for ttm:item name="altText" (#490).

skynavga has just submitted a new pull request for https://github.com/w3c/ttml2:

== Add @ttm:alt as shorthand for ttm:item name="altText" (#490). ==
Closes #490.

See https://github.com/w3c/ttml2/pull/506

Received on Saturday, 23 December 2017 22:26:12 UTC