[foms] Question to WebVTT implementers

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Sat Nov 18 23:27:41 UTC 2017

Hi all,

as part of moving WebVTT forward at the W3C, we're going through a
number of issues registered in the last call.

One of these is particularly difficult to resolve and would need some
input from implementers in browsers and elsewhere. If you are one of
those, please speak up.

In the Rendering section you'll find the following paragraph:

"Let edge margin be a user-agent-defined horizontal length, expressed
as a percentage of the width of the video’s rendering area, which will
be used to define a margin at the left and right edges of the video
into which this cue will not be placed. In situations with overscan,
this margin should be sufficient to place the cue within the
title-safe area. In the absence of overscan, this value should be
picked for aesthetics (to avoid text being aligned precisely on the
left or right edge of the video, which can be ugly)."

The request is to make this concrete when there is no overscan, i.e.
not to leave it to the individual implementer to choose an "edge
margin" for aesthetics.

My question is: is anybody using a value that is larger than 0 in the
absence of overscan and if you do, what is it?

It would really help us move forward to get some feedback on this question.


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