[whatwg] WebVTT feedback (was Re: Video feedback)

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Sat Aug 6 20:43:28 PDT 2011

On Mon, Jun 27, 2011 at 6:07 PM, Silvia Pfeiffer
<silviapfeiffer1 at gmail.com> wrote:
> On Mon, Jun 27, 2011 at 5:34 PM, Anne van Kesteren <annevk at opera.com> wrote:
>> On Mon, 27 Jun 2011 09:32:04 +0200, Silvia Pfeiffer
>> <silviapfeiffer1 at gmail.com> wrote:
>>> Note that where his implementation differs from the spec, he has made
>>> a note. There are only two such notes. I'd like to see these
>>> addressed, too.
>> Could you please post these to the list so that we not all have to read
>> those documents?
> Good point. :-) (Just search for "differs"). Here they are - with some
> additional descriptions:
> 1. [text track cue] size:
> "this document differs from specs in that way that [text track cue] is
> as width (for horizontal, height for vertical) as the widest (for
> horizontal, highest for vertical) [text track cue line] within"
> What Ronny says there is that in his implementation the default
> display size of the cue (i.e. the dark box that the cue is displayed
> in) is only as wide as the longest line in the cue (or high where
> we're dealing with vertical direction). Currently, the spec puts as a
> default S:100%.
> I personally also prefer this smaller default cue width because it
> covers less content of the video.
> 2. Cue voice tag:
> "this differs from specs in the way that opened <v> voice tags should
> be closed with </v>"
> Ronny's point is that the <v> element is expected to be closed,
> because it makes it easier to parse. So, instead of:
> 00:01:07.395 --> 00:01:10.246
> <v John Do>Hey!
> <v Jane Doe>Hello!
> he expects:
> 00:01:07.395 --> 00:01:10.246
> <v John Do>Hey!</v>
> <v Jane Doe>Hello!</v>
> I think the same is true for his implementation of the <c> class tags.
> Cheers,
> Silvia.

Adding one more to the list of things I've come across with the WebVTT spec.

I am right now trying to figure out how vertical  growing left cues
(i.e. cues with a cue rendering setting of "D:vertical") are rendered.

If nothing else is set on the cue, my expectation would be that the
cue would be rendered on the right side of the video viewport, since
it's growing to the left.

As I follow through the algorithm at
, I find that the default settings are:
* the text track cue line position default is "auto",
* the snap-to-lines flag is "true" by default,
* block flow is left to right
and in step 9 we get:
"If the text track cue writing direction is vertical growing left, and
the text track cue snap-to-lines flag is set, let x-position be zero".

I think this is incorrect and should be "..., let x-position be 100"
so as to allow the text boxes to flow onto the video viewport from the
right boundary, rather than off its left border.

Note that step 9 for vertical growing right is correct:
"If the text track cue writing direction is vertical growing right,
and the text track cue snap-to-lines flag is set, let x-position be
and the text should grow from the left boundary of the video viewport
to the right.


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