[webvtt] Unclear definition of time range

nigelmegitt has just created a new issue for https://github.com/w3c/webvtt:

== Unclear definition of time range ==
The data model for WebVTT cues omits the begin and end times, because they are defined as extensions of [text track cues](https://www.w3.org/TR/html51/semantics-embedded-content.html#cue), whose definition is:

> **A start time**
>    The time, in seconds and fractions of a second, that describes the beginning of the range of the media data to which the cue applies. 
>
> **An end time**
>    The time, in seconds and fractions of a second, that describes the end of the range of the media data to which the cue applies. 

It is unclear in any of the definitions of the begin and end times are included in the range or excluded. They should be aligned with the TTML and SMIL definitions where the begin time is included in the range and the end time is excluded, so that if there are two adjacent cues where the first cue's end timestamp is equal to the second cue's begin timestamp then the cues' presentation does not overlap.

Please view or discuss this issue at https://github.com/w3c/webvtt/issues/415 using your GitHub account

Received on Wednesday, 29 November 2017 11:21:39 UTC