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

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Mon Jun 6 02:06:13 PDT 2011


On Mon, Jun 6, 2011 at 6:04 PM, Glenn Maynard <glenn at zewt.org> wrote:
> On Mon, Jun 6, 2011 at 3:41 AM, Silvia Pfeiffer <silviapfeiffer1 at gmail.com>
> wrote:
>>
>> I don't think your example is a typical one. In my (unmeasured)
>> experience, the scrolling behaviour is much more typical.
>
> It's definitely an uncommonly complex scene to caption.  I raised it
> wondering about the quality level the format can manage in the harder
> cases.  (To be clear, this isn't something any of the popular ad hoc formats
> can do, either--this was achieved with a brittle rendering-specific hacks.)
>
> I've never seen the scrolling behavior in subtitles, though.  I think
> they're only common in live captions.

Agreed, mostly live, but also when playing back content that had live
captions. Also, we do want to support live captions here, so I think
they are relevant.


>> In fact, that example of yours is really really confusing to me. I
>> would much prefer if the text wasn't displayed on top of each other,
>> but at different locations on the screen - one to the right one to the
>> left, preferably underneath the people that speak. That is a better
>> experience. I believe that example of yours only looks that way
>> because somebody had to work around the problem that the subtitle
>> authoring format didn't allow for such explicit placement.
>
> The scene is jumping all over the place--at one point one pair is directly
> *above* the other pair in the frame.  There's no left/right speaker
> correspondance.  FWIW, I find it intuitive to read.

Even when they are above each other, you could place one on the left
at the top next to the first speaker and one on the right at the
bottom next to the other speaker.

I guess intuitions can be different. :-)


>> >> Eventually, we will want to get rid of the legacy format and just
>> >> deliver WebVTT, but they still need to display as though they came
>> >> from the original broadcast caption format for contractual reasons.
>> >
>> > I don't know what degree of sameness they expect, but as users can
>> > always
>> > override their font (implying different wrapping results, etc.), you'll
>> > never be able to guarantee that it'll look identical to the output of a
>> > more
>> > fixed format.  If captions have editing like the above, it could even
>> > result
>> > in a visible drop in quality.
>>
>> I think the opposite is true. Right now, people work around some of
>> the ways in which they really would like to render their captions
>> because the formats don't allow for example explicit placement.
>> Therefore we get poor quality captions right now. With the features
>> available, we should see better captions, not worse.
>
> Sure (most of the time), but if the contracts you refer to require that
> their content rendered with WebVTT look the same as they did in their
> original format, that won't always be possible.

Most things are actually possible - I've tried to give this a shot
with CEA-608 captions here:
http://www.w3.org/WAI/PF/HTML/wiki/Media_608_WebVTT_Conversion .
Feedback very welcome!

Cheers,
Silvia.



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