[whatwg] <video>/<audio> feedback
singer at apple.com
Fri May 8 09:25:43 PDT 2009
At 23:46 +1000 8/05/09, Silvia Pfeiffer wrote:
>On Fri, May 8, 2009 at 9:43 AM, David Singer <singer at apple.com> wrote:
>> At 8:45 +1000 8/05/09, Silvia Pfeiffer wrote:
>>> On Fri, May 8, 2009 at 5:04 AM, David Singer <singer at apple.com> 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
>>>>> resource, I think she does it on purpose. It is not clear why it is
>>>>> for the viewer to have an _obvious_ way to view the whole resource
>>>>> if it were the case, the author would provide for this.
>>>> It depends critically on what you think the semantics of the fragment
>>>> In HTML (the best analogy I can think of), the web page is not trimmed
>>>> 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
>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
>This admittedly technical difference also has an influence on the user
>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
But we can optimize for the fragment without disallowing the seeking.
Multimedia Standards, Apple Inc.
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