[imsc] Add note to tts:position that negative offsets are not allowed

palemieux has just created a new issue for https://github.com/w3c/imsc:

== Add note to tts:position that negative offsets are not allowed ==
... since regions must be within the root container region

Please view or discuss this issue at https://github.com/w3c/imsc/issues/367 using your GitHub account

Received on Thursday, 5 April 2018 21:05:25 UTC