- From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Date: Sun, 8 Sep 2013 09:27:58 +1000
- To: Glenn Adams <glenn@skynav.com>
- Cc: Cyril Concolato <cyril.concolato@telecom-paristech.fr>, public-html <public-html@w3.org>
On Sun, Sep 8, 2013 at 3:43 AM, Glenn Adams <glenn@skynav.com> wrote: > > On Fri, Sep 6, 2013 at 11:24 PM, Silvia Pfeiffer <silviapfeiffer1@gmail.com> > wrote: >> >> On Fri, Sep 6, 2013 at 2:43 AM, Glenn Adams <glenn@skynav.com> wrote: >> > >> > >> > On Thu, Sep 5, 2013 at 8:19 AM, Silvia Pfeiffer >> > <silviapfeiffer1@gmail.com> >> > wrote: >> >> >> >> > Could we compared example codes? >> >> >> >> I can give you an example: if you have TTML in-band in MP4, it's >> >> caption content, a browser has no parser and renderer for it, but can >> >> in theory extract the cues from the MP4 encapsulation - >> >> >> >> - the WHATWG spec would either not expose them to JS at all, or expect >> >> them to be exposed as VTTCue objects with @kind=metadata >> > >> > >> > This would not work, since VTTCue interprets cues of kind metadata as >> > WebVTT >> > metadata text [1], which is most definitely incompatible with TTML that >> > has >> > been serialized into intermediate synchronic document instances, each of >> > which is effectively an XML document. >> > >> > [1] >> > >> > https://dvcs.w3.org/hg/ttml/raw-file/tip/ttml2/spec/ttml2.html#extension-designations >> >> So this is what we have to resolve. Why do you think VTTCue of >> @kind=metadata can't contain TTML intermediate synchronic document >> instances (i.e. a XML document) ? > > > 1. Because WebVTT metadata text is incompatible with representing a > serialized TTML document entity unless one applies a transfer encoding > first, such as BASE64. I don't follow. Can you give an example of a serialized TTML document entity ? I thought it was XML and not binary? > 2. Because TTML is not related to VTT, and pretending that TTML is WebVTT > metadata text just confuses authors and implementers. Agreed - some renaming would be necessary. VTTCue could be called TextCue. > 3. Because TTML content will not be @kind=metadata, but rather captions, > subtitles, descriptions, etc. In other words, a renderable @kind. If it's not parsed & rendered by the browser, according to the logic expressed in this thread, it is exposed as @kind=metadata with the semantic use expressed in @inBandMetadataTrackDispatchType . Silvia.
Received on Saturday, 7 September 2013 23:28:46 UTC