[whatwg] <video> element feedback

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Thu Mar 22 13:53:48 PDT 2007

Sorry to jump into this conversation at such a late point, but I only
just joined the mailing list.

About 8 years ago, we had the idea of using fragment offsets to start
playing from offsets of media files. However, in discussions with the
URI standardisation team at W3C it turned out that fragment offsets
are only being seen by the UA that sends them, so they will never
reach the web server. This makes it impossible to use them for "play
from this offset" since obviously the offsetting should be done by the
server and avoid downloading the bunch of data that comes before the
offset point.

The only solution was to use the query "?" identifier for defining offsets.

This has been done and specified in
http://annodex.net/TR/draft-pfeiffer-temporal-fragments-03.txt, though
we never took it through full standardisation.

An implementation of that feature can be seen at
http://media.annodex.net/cmmlwiki/ where the videos are marked-up with
sections and the sections are referred to through URIs such as

Another example is used by the metavid guys: e.g.
which provides a section out of the video.

Both of the above given examples use Ogg Theora as the video, though
the files are being served through a server plugin (in both cases it
is mod_annodex) that provides for the offset functionality without
breaking the file format.


On 3/23/07, Nicholas Shanks <contact at nickshanks.com> wrote:
> On 22 Mar 2007, at 19:23, Sander Tekelenburg wrote:
> > At 18:31 +0000 UTC, on 2007-03-21, Nicholas Shanks wrote:
> >
> >> On 21 Mar 2007, at 12:43, Sander Tekelenburg wrote:
> >>
> >>> I'd like to see the spec to
> >>> require UAs support implicit anchors, so that one can link to a
> >>> specific startpoint: <URL:http://domain.example/movie.ogg#21:08>,
> >>> to mean
> >>> "fetch the
> >>> movie and start playing it at 21 minutes 8 seconds into the
> >>> movie".   [...]
> >>
> >> Well besides the fact that fragment ids cannot start with a number
> >
> > We're not talking about IDs, just fragment identifiers. My point
> > was that
> > with video, you could use fragment identifiers *without* the need
> > for the
> > author to provide IDs.
> I see your point, but i would like for fragment identifiers within a
> video to be equal to fragment IDs in text fallback content. Therefore
> they have to be constrained to the same limits.
> > the client doing the request should be smart enough to know to
> > escape the colon
> Wikipedia section IDs have lots of escaping, but it's all done by the
> wiki server, not the UA. I don't know if this is because UAs can't be
> trusted to get it right or not.
> - Nicholas.

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