[whatwg] Start position of media resources

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Tue Apr 7 14:53:50 PDT 2009

On Wed, Apr 8, 2009 at 12:26 AM, Ralph Giles <giles at xiph.org> wrote:
> On Tue, Apr 7, 2009 at 1:26 AM, Silvia Pfeiffer
> <silviapfeiffer1 at gmail.com> wrote:
>> For example, take a video that is a subpart of a larger video and has
>> been delivered through a media fragment URI
>> (http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-reqs/).
>> When a user watches both, the fragment and the full resource, and both
>> start at 0, he/she will assume they are different resources, when in
>> fact one is just a fragment of the other.
> There is a ui problem here, in that the 'seek bar' control typically
> displayed by web video players has finite resolution. It works great
> for short-form clips a la YouTube, but a 30 second segment of a two
> hour movie amounts to a few pixels. Displaying such a fragment in the
> context of the complete work makes a linear progress bar useless for
> seeking within the fragment itself, everything having been traded for
> showing that it's part of a much larger resource. Never mind that a
> temporal url can equally well reference a five minute section of a
> 20000 hour webcam archive.
> Showing a fragment in context is helpful, not just for the time
> offset, but cue points, related resources, and so on. The default
> controls the browser provides can't encompass all possible context
> interfaces, so perhaps the focus here should be on what is necessary
> to enable scripts (or browser vendors) to build more complicated
> interfaces when they're appropriate.

I think there is a misunderstanding here. The suggestion is not to
display the full timeline of the original resource and specially mark
the fragment, but to start and end the timeline with the in and out
times of the fragment. I mentioned "context" only in that the in and
out times imply that the media resource is a fragment of a larger
resource. Not that the full context is actually displayed in the


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