W3C home > Mailing lists > Public > wai-xtech@w3.org > December 2009

Video and... Re: <device> advice

From: Charles McCathieNevile <chaals@opera.com>
Date: Wed, 23 Dec 2009 13:36:15 +0100
Cc: wai-xtech@w3.org
To: "Ian Hickson" <ian@hixie.ch>
Message-ID: <op.u5d5apbgwxe0ny@widsith.local>
On Thu, 17 Dec 2009 05:09:41 +0100, Ian Hickson <ian@hixie.ch> wrote:

>> On Tue, 15 Dec 2009 22:47:45 +0100, Ian Hickson <ian@hixie.ch> wrote:
>> > ... I've been looking specifically at how to expose
>> > Webcams to Web pages:
> I've checked in the most recent changes to the draft above into the
> html-device draft mentioned here:
>    http://lists.w3.org/Archives/Public/public-html/2009Dec/0355.html
> ...that is:
>    http://dev.w3.org/html5/html-device/

Thank you.

It is not clear how to *send* the data - the example I am looking at seems
to play locally, and unless you have something to serve content like Opera
Unite I don't see where you plan to put the Stream so someone else can
look at it. Video chat with myself isn't so compelling. Am I missing
something, or is the draft still missing something?

A few thoughts. Note that the answers to these may well be found in making
the video and audio elements support accessibility (and the questions are
relevant there) even if this element never goes anywhere.

1. I don't see that you need to solve the codec problem independently of
the general value of solving it for the video element. I.e. if there is a
baseline format that all user agents support then that makes life much
simpler for everyone, but this use case is about two individuals who
(presumably) have some kind of relationship - whether that's for a
personal chat, or a paid webcam service. It would seem that there is far
less problem in selecting an appropriate channel in this case than when a
content producer wishes to broadcast.

2. It is not clear how I would add (e.g.) captions and similar
accessibility accommodations into the stream, such as a second video using
a signed interpreter. Some use cases:

2.1 A group of people are meeting, via audio. As a combination aide
memoire, record, means to avoid clogging the audio channel with
interruptions, and accommodation for a deaf member of the group, they also
run an associated live text channel. These two resources are perceived as
more or less synchronised by the participants (who therefore also add
running commentary relying on the synchronisation to provide context). Yet
it is unclear how to record this text chat with the stream in the current

2.2 A University offers courses in "semi-presence" mode, with students
attending some classes and following others by video. A masters program in
this mode has attracted students from around the globe, including deaf
students from 3 countries. All the lectures are automatically recorded in
video, and to meet its students' needs the university provides a sign
language interpreting service, making a related video available for each
of the three sign languages used by the students. How do you offer these
tracks together as an (apparently) integrated stream?

(I'll leave this here, having written it a while ago and not had time to  
give it more thought since).



Charles McCathieNevile  Opera Software, Standards Group
       je parle français -- hablo español -- jeg lærer norsk
http://my.opera.com/chaals       Try Opera: http://www.opera.com
Received on Wednesday, 23 December 2009 12:36:55 UTC

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