At 8:29 +1000 8/04/09, Silvia Pfeiffer wrote:
> My mental analogy was HTML, where an acnhor takes you to that part of the
page as a convenience, but nothing stops you from navigating away. And in
the case where the UA optimizes for showing that section (by suitable
handshakes/translations with the server), again, it could present a UI which
offers other times -- at the expense of more handshakes.
Yes, I understand that analogy. But because video can be a very long
resource, media fragment URIs cannot be restriced to client-side
offsetting. Think e.g. about wanting the last 2 minutes out of a 5
hour discussion downloaded to your mobile phone.
The media fragment WG decided that fragment addressing should be done
with "#" and be able to just deliver the actual fragment. (BTW: this
is in contrast to the temporal URIs that were specified for Annodex,
where chopping happened in the UA for "#" and on the server for "?").
But there is a huge difference between
a) the UA MUST optimize for the chosen fragment, and may/should offer
the rest of the resource to the user (at the possible expense of more
network traffic)
and
b) the UA MUST only offer the chosen fragment to the user, and
optimize network traffic and downloads for just that section, and
MUST NOT allow navigation outside the indicated range
Unfortunately, it does make a difference to the page author which of
these is talked about (and, lacking anything else, (a) is probably
what is expected).
--
David Singer
Multimedia Standards, Apple Inc.
