Re: Timed tracks

On Fri, 07 May 2010 05:53:20 +0800, Tab Atkins Jr. <jackalmage@gmail.com>  
wrote:

> On Thu, May 6, 2010 at 2:25 PM, John Foliot <jfoliot@stanford.edu> wrote:
>> Tab Atkins Jr. wrote:
>>>
>>> SRT is the closest-to-ideal existing format,
>>
>> Tab, with all due respect, what documented facts is this bold assertion
>> based upon? <em>URLs would be most appreciated here, as the Media  
>> Sub-Group
>> are assembling a needs requirement document at this time.</em>
>
> All of the use-cases of actual caption use on the web, collected on
> the WHATWG wiki at
> http://wiki.whatwg.org/wiki/Use_cases_for_timed_tracks_rendered_over_video_by_the_UA.
>  Additionally, API-level access use-cases for captions on the web have
> been collected at
> http://wiki.whatwg.org/wiki/Use_cases_for_API-level_access_to_timed_tracks.
>
>
>> As co-chair of the Media Sub-Group at the W3C Accessibility Task Force  
>> for
>> HTML5, active participants (including, significantly, engineers from the
>> related browser manufacturers) have been discussing Time Text formats  
>> for
>> some time now, and a recent survey (2010-03-08 to 2010-03-11) of the  
>> larger
>> a11y Task Force showed almost equal support for the minimal SRT format  
>> as
>> well as a more robust format, likely DFXP/TTML and/or a profile of that.
>> - http://www.w3.org/2002/09/wbs/44061/media-text-format/results
>>
>> The general consensus (and others are free to correct me) was that SRT  
>> was
>> at best a minimal time-stamp format that could be used, but that it did  
>> not
>> meet the 'robustness' test for all aspect of accessibility. Suggesting  
>> that
>> it is the "closest-to-ideal" is pure folly and opinion at this time, and
>> does not accurately reflect the opinion of those who are working  
>> closely at
>> this subject (again, including engineers from Microsoft, Apple, Opera  
>> and
>> Mozilla directly involved with <video> implementation in the browsers).  
>> In
>> fact, Maciej himself suggested (in his survey response): "I don't think  
>> it's
>> necessary to require a specific format for the initial proposal. It  
>> seems
>> like requiring any one format will just make it more controversial."
>
> Indeed, plain SRT is pretty minimal, and doesn't address many of the
> documented use-cases.  But it's very simple to both author and parse,
> and the extensions needed to make it handle all the aforementioned
> use-cases are pretty minimal.  It's also pretty common, apparently
> especially so amongst amateur subbers, which implies that it probably
> addresses the needs and desires of average authors pretty well.
>
> It may be that we end up needing to support multiple formats, such as
> perhaps a profile of TTML.  But I'd like to avoid that if at all
> possible, and from what I understand implementors would too.

I am one of those browser vendor representatives that voted in the linked  
survey, supporting SRT only. From what I have read of the TTML spec, I do  
not want to support it in Opera, mainly because it fails to make use of  
CSS for styling.

>> Continue to expect significant and vocal opposition to this newly
>> re-invented Time-stamp wheel, which apparently sprang to life earlier  
>> this
>> week from the editor of the WHAT WG, as a complete and total surprise to
>> Media Captioning experts and Accessibility specialists of all stripes  
>> within
>> the W3C (such as Geoff, who's years of involvement within NCAM/WGBH -  
>> the
>> 'inventors' of captioning for television "video media" - carries  
>> significant
>> weight, research and experience when it comes to understanding both user
>> requirements, as well as an understanding of implementation issues).
>
> No, the use-cases have been collected for a while, in hand with
> significant effort from Silvia Pfeiffer.  No need to invent a fiction
> of Hixie creating these things out of whole cloth.

Like Silvia, I have also been taking part in this discussion. I don't  
think WebSRT is going to be immediately perfect, but the general direction  
is one I approve of. If there are use cases it cannot serve, now is the  
time to raise them. It may very well turn out that we need a second  
complex format, but that doesn't negate the usefulness of WebSRT.

(Hixie has participated very little in these discussions, so it's hard to  
frame this as his creation alone.)

-- 
Philip Jägenstedt
Core Developer
Opera Software

Received on Friday, 7 May 2010 04:35:43 UTC