Re: WebVTT Text Positioning

> Is the conversion spec not clear enough on this?

Not really.  Trying to reconcile what you had previously said, "*Line
height is set by CSS automatically based on font size"**.  *

with c/s 1.4:

   - *The line height is defined as 5.33% of the video height, because
   CEA-608 requires 15 character rows to be rendered on 80% of the video
   rendering area’s height.*
   - *The font size is defined from the line height by dividing it by 1.3;
   this is to make sure there is enough space for the characters in a line.*

*
*
and c/s 1.5:

*The actual height and width of the caption window depends, however, on the
actual font size. *


So, according to 1.4, font size is line height /1.3, and line height is
defined as 5.33% of video.  This makes sense, and suggests that the
renderer will select the appropriate line height and font size based on
video window size.  However, your comment and 1.5 seem to suggest the
inverse, that the dimensions depend on font size.

Is there is an obvious point that I am missing?

Thanks,
D


On Tue, Jun 25, 2013 at 8:09 PM, Silvia Pfeiffer
<silviapfeiffer1@gmail.com>wrote:

> Is the conversion spec not clear enough on this?
> https://dvcs.w3.org/hg/text-tracks/raw-file/default/608toVTT/608toVTT.html
>
> Silvia.
>
> On Tue, Jun 25, 2013 at 11:01 PM, David Ronca <dronca@netflix.com> wrote:
> > For 608 captions, the line height should be (display_height - safe_area)
>  /
> > 15.  The font size should be such that a monospaced letter will fill one
> > cell.  How does WebVTT handle this?
> >
> > Thanks,
> > David
> >
> >
> >
> > On Tue, Jun 25, 2013 at 6:03 PM, Silvia Pfeiffer <
> silviapfeiffer1@gmail.com>
> > wrote:
> >>
> >> On Wed, Jun 26, 2013 at 10:42 AM, David Ronca <dronca@netflix.com>
> wrote:
> >> > If I want to position CEA608 text at row 10, column 10 the cue might
> >> > look
> >> > like this:
> >> >
> >> > Cue-8 00:00:52.000 --> 00:00:54.000 position:35% line:58* align:left
> >> > size:25% Tis a test
> >> >
> >> > There are 10 characters so the size is 10* cell width (2.5%).
> Wondering
> >> > if I
> >> > also need to specify the height, which would be one row (5.33%), but I
> >> > see
> >> > no way to do this with the WebVTT spec. Is line height baked into the
> >> > implementation?
> >>
> >> Line height is set by CSS automatically based on font size, and there
> >> is no cue setting for it because there shouldn't be a need to change
> >> it. However, you can always set line-height through CSS.
> >>
> >> Silvia.
> >
> >
>