[whatwg] HTML 5 video tag questions

Tab Atkins Jr. jackalmage at gmail.com
Mon Jul 13 12:28:45 PDT 2009

On Mon, Jul 13, 2009 at 2:15 PM, Philip Jägenstedt<philipj at opera.com> wrote:
> On Mon, 13 Jul 2009 20:38:11 +0200, Tab Atkins Jr. <jackalmage at gmail.com>
> wrote:
>> On Mon, Jul 13, 2009 at 1:33 PM, Boris Zbarsky<bzbarsky at mit.edu> wrote:
>>> Philip Jägenstedt wrote:
>>>> It would have to be part of the resource selection algorithm. Since that
>>>> waits for new source elements indefinitely, when exactly would you
>>>> decide to
>>>> switch to fallback content? Bad solutions include special-casing static
>>>> markup and/or (falsely) assuming that scripts will not insert more
>>>> source
>>>> elements at some point. If fallback content is defined simply as the
>>>> content
>>>> of the video element I also can't figure out any other solutions.
>>> A <source> that says "use the content"?
>>> -Boris
>> Ie inserting <source fallback> or <source contents>.  If both @src and
>> @fallback are specified on a <source>, it is treated like a <source
>> src><source fallback>; that is, it first tries the @src attribute, and
>> if that doesn't work, then it goes to the fallback content.
> That would require the parser to inspect an attribute to determine if the
> element is a void element (one that does not have a closing tag) or not,
> which I've been told is not very nice. Are there any other such cases?

Hm?  I'm not sure what you mean here.  It would work like this:

  <source src="foo">
  <source src="bar">
  <source fallback>
  <p>I'm some fallback content!</p>

You'll see the <p> if the browser doesn't support <video>, or if the
resource selection algorithm hits that third source and hasn't found
anything it can play yet.  It wouldn't change whether the <source> is
a void element or not.

(You could also just put @fallback on the second <source> and drop the
third <source> entirely for the same effect.)

> This is why I suggested <video><source
> src="cant.play.ogg"><new-fallback-element>Ooops!</new-fallback-element></video>
> I still think the use of this is questionable though.

I'm not sure why you think the usecase is questionable.  It seems
pretty clear - it'd be nice to have a non-script way of showing
content (specifically, alternate video players) when the browser
supports <video> but can't play any of the provided sources.


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