[whatwg] <video>/<audio> feedback

[Silvia Pfeiffer]

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
>>>> 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.

In contrast, downloading a snippet of video compared to the full video
will make a huge difference, in particular for long-form video.

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.

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.

Thus, while comparing media fragments to HTML fragments is a simple
way to introduce the concept - and I use it, too, to explain to my
less technical peers - it doesn't really help for detailed
specifications.

Regards,
Silvia.