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Re: [me-media-timed-events] DataCue or a more specific API for DASH and emsg events

From: Silvia Pfeiffer via GitHub <sysbot+gh@w3.org>
Date: Fri, 15 Jun 2018 22:34:33 +0000
To: public-web-and-tv@w3.org
Message-ID: <issue_comment.created-397758932-1529102072-sysbot+gh@w3.org>
None of this is new IP - all of it has been discussed many times over in the TextTrack CG, WHATWG and the HTML WG. A change to specs and implementations isn't going to take place here anyway.

What we can get to here is a feeling for what preferences people have in this community before taking it to the right community to address it.

@boblund has nicely listed the alternatives. Here are the problems with each:

1) TextTrackCue.text
* does not exist in the HTML5 spec any longer
* will most likely not come back in the HTML spec
* needs an extra way to specify the data type, e.g. .dataType attribute

2) VTTCue.text
* exists in HTML5 API, is supported by browsers
* WebVTT can bring metadata into HTML pages via `<track>` element now
* needs an extra way to specify the data type, e.g. .dataType attribute

3) DataCue.data
* exists in spec, but is not implemented in browsers
* needs an extra way to specify the data type, e.g. .dataType attribute
* seems sensible in the long run to allow this as a generic framework for associating structured data with a time interval

4) a dedicated EmsgEventCue
* needs a completely new spec and implementation
* seems overkill for anything that doesn't have a huge use in practice

So, your decision may depend on how long you are prepared to wait for it to become usable in a Web browser.

I suggested (2) as an interim measure, but it's not the best and most generic solution. It will, however, work now and it has the advantage that you can also carry emsg events in a WebVTT file and associate it with a video element via the `<track>` element in HTML right now. 

Whether your preference is on (3) or (4) going forward should depend on the size of your "market" - how many users and use cases do you see? I personally would prefer to start with (3).

So, give your opinions here and then you'll need to take it straight to the HTML WG or the WHATWG for specification and implementer buy-in. If you want to pass it by any further forums for further buy-in, go ahead also.

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Received on Friday, 15 June 2018 22:34:37 UTC

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