Re: Captioning for live video

On Tue, Dec 11, 2012 at 10:03 PM, Simon Pieters <simonp@opera.com> wrote:

> On Tue, 11 Dec 2012 10:24:06 +0100, Silvia Pfeiffer <
> silviapfeiffer1@gmail.com> wrote:
>
>  1. Solution in HTML
>>
>> We can realize this by introducing an "append()" function for
>> TextTrackCues
>> in HTML. Then at least real-time caption functionality can be implemented
>> in JavaScript.
>>
>> It could be something like:
>>
>> cue.append(text, duration, timestamp)
>>
>> Which would simply append the "text" to the cue's text content and
>> "duration" to the cue's end time. It could even add a timestamp in front
>> of
>> the text to capture when the word was provided.
>>
>
> Cues are mutable in the API already. You can set the .text (with
> timestamps if you want) and .endTime IDL attributes.
>

OK, so one would have to replace .text with .text + newText . That works
then.


 2. Solution in WebVTT
>>
>
> Separately from WebVTT syntax issues, currently the spec does not support
> streaming of WebVTT in <track>.
>

That's what https://www.w3.org/Bugs/Public/show_bug.cgi?id=18029 is about.
I continue to believe that similarly to how we can stream a video live to a
<video> element, we should be able to stream text to a <track> element and
synchronize it from the cue time stamps.

Apart from <track>, WebVTT is also being used in HLS and there, when used
for live communication, a better resolution than a sentence would be
necessary.

Silvia.