Re: "WebVTT file using only nested cues"

On Feb 28, 2012, at 6:53 , Glenn Maynard wrote:

> On Tue, Feb 28, 2012 at 12:15 AM, Simon Pieters <simonp@opera.com> wrote:
> "Furthermore, if the element's track URL identifies a WebVTT resource, and the element's kind attribute is in the chapters state, then the WebVTT file must be both a WebVTT file using chapter title text and a WebVTT file using only nested cues. [WEBVTT]"
> 
> http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#the-track-element
> 
> Shouldn't this requirement be in WebVTT, not <video>, so it's a WebVTT requirement?  Currently, WebVTT itself doesn't make this restriction; it's an additional restriction imposed on WebVTT when it happens to be used by <video>.  Other consumers of the file format (eg. WebM) might not make that restriction, potentially creating incompatibilities.  (I suppose incompatibilities are only theoretical, since this seems like one of those odd authoring requirements where the behavior has to be defined even if it isn't followed.  WebVTT itself seems the natural place for this, though.)


It might be kinda odd.  One would have to say in the VTT spec. "When the VTT file is externally identified as a Chapter Track, then …", and in the HTML spec. say that the kind attribute being in the chapters state (what odd language!) identifies it as a chapter track.

(Thank you for the link to what a nested cue is used for).


David Singer
Multimedia and Software Standards, Apple Inc.