[imsc] Pull Request: Clarify requirement that regions are contained within root container

palemieux has just submitted a new pull request for https://github.com/w3c/imsc:

== Clarify requirement that regions are contained within root container ==
Closes #239

See https://github.com/w3c/imsc/pull/240

Received on Tuesday, 30 May 2017 17:30:53 UTC