[whatwg] media resources: addressing media fragments through URIs spec

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Thu Jul 1 02:46:00 PDT 2010

BTW: I will try and make a screencast of that firefox plugin, which
should clarify things further. Stay tuned...

On Thu, Jul 1, 2010 at 7:44 PM, Silvia Pfeiffer
<silviapfeiffer1 at gmail.com> wrote:
> Hi Jonas,
> On Thu, Jul 1, 2010 at 4:41 AM, Jonas Sicking <jonas at sicking.cc> wrote:
>> Hi Silvia,
>> Back in may last year I brought [1] up the fact that there are two use
>> cases for temporal media fragments:
>> 1. Skipping to a particular point in a longer resource, such as
>> wanting to start a video at a particular point while still allowing
>> seeking in the entire resource. This is currently supported by for
>> example YouTube [2]. It is also the model used for web pages where
>> including a fragment identifier only scrolls to a particular point,
>> while allowing the user to scroll to any point both before and after
>> the identified fragment.
>> 2. Only displaying part of a video. For example out of a longer video
>> from a discussion panel, only displaying the part where a specific
>> topic is discussed.
>> While there seemed to be agreement [3][4] that these are in fact two
>> separate use cases, it seems like the media fragments draft is only
>> attempting to address one. Additionally, it only addresses the one
>> that has the least precedence as far as current technologies on the
>> web goes.
>> Was this an intentional omission? Is it planned to solve use case 1
>> above in a future revision?
>> [1] http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-May/019596.html
>> [2] http://www.youtube.com/watch?v=fyQrKvc7_NU#t=201
>> [3] http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-May/019718.html
>> [4] http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-May/019721.html
> I think you may have misunderstood the specification. Use case 1 is
> indeed the main use case being addressed in the specification. There
> is a Firefox plugin implementation[1] of the specification that shows
> exactly use case 1 in a video element - a URI with a fragment such as
> video.ogv#t=40,50 is being included in a <video> element and the
> effect is that the video is displayed from 40s to 50s, but the
> transport bar (or controls) are still those of the complete resource,
> so you can still seek to any position.
> To be sure, this is just a recommendation of how it is supposed to be
> implemented (see
> http://www.w3.org/TR/media-frags/#media-fragment-display). The group
> only defined what URIs look like that point to such a segment - it
> cannot prescribe what an application (such as a HTML document) does
> with the URI. I would propose that this discussion should be had about
> HTML5 and a sentence be added to the HTML5 spec on how UAs are
> expected to deal with such segments.
> Further, if you are indeed only interested in a subpart of the
> original media resource and want to completely blend out all context
> (i.e. all other bits of the media resource), you should be using the
> URI query addressing method instead of the URI fragment, e.g.
> video.ogv?t=40,50. This URI is supposed to create a new resource that
> consist only of the segment - it will only do so, of course, if your
> server supports this functionality.
> All of this is described in more detail in the spec [2]. If that is
> unclear or anything is confusing, please do point it out so it can be
> fixed.
> Best Regards,
> Silvia.
> [1] http://www.w3.org/2008/WebVideo/Fragments/code/plugin/ (expect some bugs)
> [2] http://www.w3.org/TR/media-frags/

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