On Wed, Dec 11, 2013 at 5:36 AM, David Singer <singer@apple.com> wrote: > > On Dec 10, 2013, at 12:56 , Glenn Adams <glenn@chromium.org> wrote: > > > * we want this to be only one of many possible implementation choice > > and > > * we want there to be a simple expression of the timed cues that is not > dependent on an implementation choice > > > > Which would require the "simple expression" to be a semantic/stylistic > superset of formats, which HTML/CSS is, but WebVTT isn’t. > > No, that’s a non-sequitur. You asked why we don’t simply assume HTML, > CSS, and Javascript and do titling using XMLHttpRequest, or the like. That > assumes an *implementation* using HTML. > Since VTT is normatively defined as a mapping to HTML/CSS and we are preparing to do this for TTML, and since TextTrackCue assumes that a rendered form of a cue implements getCueAsHTML() which returns a renderable HTML/CSS mapping, then someone already appears to be making this assumption (that *some* implementation uses HTML... not that every implementation *must* use HTML). > > The simple expression needs to express what we need in captioning, > independent of the implementation thereof. Why does it need to be a > ‘superset’ of anything? > If both VTT and TTML (via new work in TTML2) are going to define their normative rendering semantics using HTML/CSS, then either HTML/CSS needs to be a superset of their intended rendering or some rendering will be incomplete, yes?
Received on Tuesday, 10 December 2013 22:45:43 UTC