[ttml2] Add missing @extent attribute to isd:isd.

skynavga has just created a new issue for https://github.com/w3c/ttml2:

== Add missing @extent attribute to isd:isd. ==
Both `ttp:displayAspectRatio` and `ttp:pixelAspectRatio` are defined for use on `isd:isd`; however, an `extent` attribute was neglected to be define (but is already implemented and used in TTX/TTPE). In order to support the use of `rw` and `rh` units in ISDs, as well as complete the triangle for (SAR/DAR/PAR), we need to define an `extent` attribute to take two pixel based length expressions for use on `isd:isd`.

Please view or discuss this issue at https://github.com/w3c/ttml2/issues/919 using your GitHub account

Received on Saturday, 21 July 2018 09:46:38 UTC