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

[Silvia Pfeiffer]

On Tue, Jul 6, 2010 at 2:45 PM, Marques Johansson <marques at displague.com> wrote:
> On Wed, Jun 30, 2010 at 8:11 AM, Silvia Pfeiffer <silviapfeiffer1 at gmail.com>
> wrote:
>>
>> Hi all,
>>
>> The W3C WG for media fragments has published a Last Call Working Draft
>> at http://www.w3.org/TR/media-frags/ .
>>
>> The idea of the spec is to enable addressing sub-parts of audio-visual
>> resources through URIs, such as http://example.com/video.ogv?t=10,40
>> to address seconds 10-40 out of video.ogv. This is relevant for use in
>> the <audio> and <video> elements and can help focus the playback to a
>> specific subpart.
>
>
> When dealing with timed content - shouldn't there be a relative URI meaning
> from the current time to the designated time.  I'm thinking of something
> like:
> http://example.com/video.ogv#t=,40
> Which would be used to continue a piece a playing media up to the 40 second
> point and then stop.
> This could prevent a fetch by the UA to the start of the media fragment
> which could be especially useful if the media is marked as no-cache.
> I'm thinking an article could outline links on a page each of which would
> cause a related video to continue playing up to the point specified in the
> link and then stop - giving the reader a chance to catch up.
> This also brings up the matter of link targets.  Shouldn't I be able to do
> something like this:
> <video name="presentation"></video>
> <a href="#,50" target="presentation">Next Slide</a>
>

Wouldn't they all have a start time, too? E.g. the start time of a
slide to the end time of the slide?

When you write a Web page, there is no such thing as "now" on the page
- all you can reasonably assume when loading a media resource is to
start at 0, so I cannot see your links work in the way that you're
asking for. You can of course always do what you want with JavaScript
though.

Cheers,
Silvia.