Re: [tvcontrol-api] Support for do-it-now stream events

Some more thoughts on TVTriggerCue:

At other places we discuss mapping of the API to signalling in the TV 
or Radio broadcast, I think it would be useful for the triggers as 
well.

Doing this will also help to see if the API works with certain 
broadcast specs.

A DSMCC stream event for instance:

name - the stream event name
type   - ? should it be context or time?
url      - I assume this is a URL where the triggers are carried. 
Stream events are identified by URL of the stream event object and a 
name. So this could be the URL of the stream event object, i.e. 
dvb://1.2.3.4/seobj
additionalData - payload of the stream event

Now the question is how can an app listen for stream events and how 
does it receive them.
Is the app required to use addTextTrack or is the user agent required 
to add a text track if it discovers stream events signalled in the 
media stream? The latter could be difficult as the user agent does not
 know the location of the stream event object in all cases, with HbbTV
 the stream event object could come from a web server. However, there 
is no method defined yet that allows to init a new TVTriggerCue.

As I said in my first comment, stream events have no start time and 
end time. They trigger an event when they arrive at the TV.
TextTracks have a oncuechange event, that could be said to be called 
when a stream event arrives. However, there is no API defined to check
 which cue caused the change. The app can only check which cues are 
active. And a cue is active when the current play position is between 
start and end of the cue.

As a conclusion I think there are at least two open issues when 
mapping the TVTrigger to stream events.

Any opinions?

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Received on Monday, 5 December 2016 15:38:09 UTC