At 23:46 +1000 8/05/09, Silvia Pfeiffer wrote:
On Fri, May 8, 2009 at 9:43 AM, David Singer <[email protected]> wrote:
At 8:45 +1000 8/05/09, Silvia Pfeiffer wrote:
On Fri, May 8, 2009 at 5:04 AM, David Singer <[email protected]> wrote:
At 8:39 +0200 5/05/09, KÞi"tof Îelechovski wrote:
If the author wants to show only a sample of a resource and not the
full
resource, I think she does it on purpose. It is not clear why it is
vital
for the viewer to have an _obvious_ way to view the whole resource
instead;
if it were the case, the author would provide for this.
IMHO,
Chris
It depends critically on what you think the semantics of the fragment
are.
In HTML (the best analogy I can think of), the web page is not trimmed
or
edited in any way -- you are merely directed to one section of it.
There are critical differences between HTML and video, such that this
analogy has never worked well.
could you elaborate?
At the risk of repeating myself ...
HTML is text and therefore whether you download a snippet only or the
full page and then do an offset does not make much of a difference.
Even for a long page.
you might try loading, say, the one-page version
of the HTML5 spec. from the WhatWG site...it
takes quite a while. Happily Ian also provides a
multi-page, but this is not always the case.
In contrast, downloading a snippet of video compared to the full video
will make a huge difference, in particular for long-form video.
there are short and long pages and videos.
But we're talking about a point of principal
here, which should be informed by practical, for
sure, but not dominated by it.
The reason I want clarity is that this has
ramifications. For example, if a UA is asked to
play a video with a fragment indication
#time="10s-20s", and then a script seeks to 5s,
does the user see the video at the 5s point of
the total resource, or 15s? I think it has to be
5s.
So, the difference is that in HTML the user agent will always have the
context available within its download buffer, while for video this may
not be the case.
I'm sorry, I am lost. We could quite easily
extend HTTP to allow for anchor-based retrieval
of HTML (i.e. convert a 'please start at anchor
X' into a pair of byte-range responses, for the
global material, and then the document from that
anchor onwards).
This admittedly technical difference also has an influence on the user
interface.
If you have all the context available in the user agent, it is easy to
just grab a scroll-bar and jump around in the full content manually to
look for things. This is not possible in the video case without many
further download actions, which will each incur a network delay. This
difference opens the door to enable user agents with a choice in
display to either provide the full context, or just the fragment
focus.
But we can optimize for the fragment without disallowing the seeking.
--
David Singer
Multimedia Standards, Apple Inc.
