2013-05-30 14:19:55: Created issue '<p> fade-up and –down' nickname <p> fade-up/down owned by Pierre-Anthony Lemieux on product TTML.next, description '[The following is extracted from the liaison received from SMPTE at https://lists.w3.org/Archives/Member/w3c-archive/2012Sep/0214.html]
See Sections 6.1.4 and 6.1.5 at ST 428-7, and Section 8.2.13 at TTML.
It shall be possible to apply the tts:opacity style parameter to an individual <p> element. The parameter shall be animatable.
In order to avoid markup duplication when tts:opacity is used to create fade-up and -down effects, it shall be possible to either (a) define a given sequence of <set tts:opacity="…"> elements once and apply it to multiple <p> elements, or (b) allow that linear interpolation be applied between <set> values.
' non-public [Pierre-Anthony Lemieux]