IRC log of htmlcue on 2015-10-28

Timestamps are in UTC.

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logging to http://www.w3.org/2015/10/28-htmlcue-irc
01:36:40 [nigel]
rrsagent, make logs public
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Present+ nigel
01:36:48 [nigel]
chair: nigel
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preent +hober
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s/preent/present/
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present +hober
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Present+ Jean-Claude_Dufourd
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Giri Mandyam, Qualcomm, joining HTMLCue breakout session
01:47:33 [giuseppe]
present+ giuseppe
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cribe: giuseppe
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scribe: giuseppe
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01:47:49 [JP_Abello]
present+ JP Abello
01:47:57 [gmandyam]
present+ Giri Mandyam
01:47:57 [giuseppe]
Nigel: in the TTWG we are looking at two formats
01:48:01 [kurosawa]
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TTML and WebVTT
01:48:10 [kurosawa]
present+ Kurosawa
01:48:25 [Yamane]
present+ Taketoshi Yamane
01:48:33 [kinjim]
present+ Kinji Matsumura
01:48:38 [akitsugu]
present+ Akitsugu Baba
01:48:39 [giuseppe]
for webvtt we have a cue, with in/out and style
01:48:44 [giuseppe]
when we look at other formats
01:48:54 [giuseppe]
we are asking ourselves how we implement them in the rbrowser
01:49:26 [giuseppe]
dash.js is trying to use texttrackcue to support other tt formats
01:49:47 [giuseppe]
but to do that you need to overload the texttrackcue interface
01:49:59 [giuseppe]
because that is not designed to handle something else then webvtt
01:51:38 [giuseppe]
the question is why do we need a specific vtt cue, can we have a more generic cue mechanism that can support more formats
01:51:48 [giuseppe]
for example can we have an html cue
01:51:54 [giuseppe]
that only have in/out and an html payload
01:52:13 [giuseppe]
that the browser can attach that html payload on in/out
01:52:30 [giuseppe]
or better attach on in, remove on out
01:53:56 [giuseppe]
the idea with texttrack is to separate matadata in different tracks
01:54:20 [giuseppe]
in ttml structure mixes different things in one format (text and style and metadata)
01:54:32 [giuseppe]
status of this is that htmlcue is an idea
01:54:41 [giuseppe]
ttwg presented the idea to the whatwg
01:54:53 [giuseppe]
the feedback was there could be some unintended consequences
01:55:14 [giuseppe]
example what happens if the html contains a script
01:55:19 [giuseppe]
or what happens to the browser context
01:55:35 [giuseppe]
so I'm interested to discuss these issues and how to appraoch the problem
01:56:45 [giuseppe]
giuseppe: is the main goal here to support ttml?
01:57:19 [giuseppe]
nigel: yes mainly, but not only
01:58:01 [giuseppe]
ttml could be one source of information for the htmlcue track
01:58:32 [giuseppe]
simon: one issue with this
01:58:43 [giuseppe]
is security, if you allow all html in the htmlcue
01:58:54 [giuseppe]
subtitles usually don't have scripting
01:59:22 [giuseppe]
the other issue is if we assume thatw e need to subset html, does it still support the use cases you want to address
01:59:38 [giuseppe]
currently with wbvtt you can use a metadata track
01:59:47 [giuseppe]
and you can use javascript and render it
02:00:04 [giuseppe]
and there you don't have the security problem
02:00:49 [giuseppe]
why can't you use the webvtt metadata track and expose ttml then render in the page?
02:01:05 [giuseppe]
giri: the problem is, the html spec allows for 250ms delay
02:01:23 [giuseppe]
... and this might be an issue for things like subtitles
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02:01:49 [giuseppe]
giuseppe: does it mean we need a high priority cue?
02:02:35 [giuseppe]
simon: are you sure this delay of 250ms apply to the cues?
02:03:31 [giuseppe]
(room checking the spec)
02:04:55 [giuseppe]
nigel: so the requirement is that accuracy has to be greater then 250ms
02:05:25 [giuseppe]
simon: the 250ms is only for the timesupdate
02:05:47 [giuseppe]
but should not apply to the cues
02:07:55 [giuseppe]
jc: cyril has done a demo using the events
02:10:45 [giuseppe]
x1: the secureity issue here i major
02:11:11 [giuseppe]
maybe is better to look at extending the current api
02:12:07 [giuseppe]
giri: what about the idea of using a sandbox
02:12:44 [giuseppe]
nigel: you could block any script and maybe threat it like an iframe
02:15:30 [giuseppe]
simon: the metadata kind is designed to support this use case
02:17:48 [giuseppe]
xxx: could there be a problem of performance, is the html is too complex?
02:19:34 [giuseppe]
jc: maybe you can do some testing and show if there is really a performance problem, and if you really need some htmlcue
02:22:01 [giuseppe]
nigel: so the proposed model is to use existing track cue with metadata kind, although is not metadata, and then render in javascript
02:24:07 [giuseppe]
xxx: there are of course some problems
02:24:21 [giuseppe]
for example the browse might need to expose the subtitles preferences
02:24:39 [giuseppe]
so that the js renderer know what to do
02:25:35 [giuseppe]
the other problem is that you cannot use the defaul player controller
02:26:01 [giuseppe]
but if you are doing this custom subtitlles handling you can probably build your custom controls as well
02:29:04 [giuseppe]
giri: what happens if kind is set to something other then the allowed values
02:29:10 [giuseppe]
simon: I think it defaul to subtitles
02:29:52 [giuseppe]
xxx: the question is still, wouldn't be better to have some easier way to support this
02:31:50 [giuseppe]
also, it it's easier for people to transalte from ttml to html then to vtt
02:32:07 [nigel]
s/xxx/andreas
02:34:13 [giuseppe]
because for webvtt you need to know both the sintax but also the renderin model that is different
02:36:18 [giuseppe]
all: discussion about if it's feasible to make a subset of html suitable for this htmlcue
02:36:40 [giuseppe]
... some people concerned that subsetting html has been done before and always failed
02:36:47 [giuseppe]
we should not try to do it again
02:37:04 [giuseppe]
nigel: isn't this very similar to sandboxing?
02:40:06 [giuseppe]
simon: one of the reason I think this si different, is because there is no way to disable fetching external resources, and I think we need that
02:40:36 [giuseppe]
nigel: why should we do that, images might be needed
02:43:01 [giuseppe]
simon: but then you might have a privacy resource
02:43:10 [giuseppe]
s/resource/issue/
02:44:02 [giuseppe]
e.g. an external resource/server could now monitor videoplayout events, monitor what you watch
02:44:15 [giuseppe]
something that was not possible before (only the internal scripting of the page could do it)
02:47:20 [giuseppe]
xxx: the image issue could be solved using data: ruls
02:47:34 [giuseppe]
s/ruls/urls/
02:52:51 [giuseppe]
action: fiel a feature request to expose user preferences about subtitles to the page
02:53:38 [giuseppe]
s/fiel/file/
02:57:33 [giuseppe]
action: work on a prototype using the metadata kind for texttrack and to try and highlight limitation and issues
03:02:10 [nigel]
rrsagent, make minutes
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I have made the request to generate http://www.w3.org/2015/10/28-htmlcue-minutes.html nigel
03:03:29 [nigel]
Meeting: HTMLCue breakout, TPAC 2015
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I have made the request to generate http://www.w3.org/2015/10/28-htmlcue-minutes.html nigel
03:04:09 [nigel]
Present+ glenn_adams, jerry_smith
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rrsagent, make minutes
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I have made the request to generate http://www.w3.org/2015/10/28-htmlcue-minutes.html nigel
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