[whatwg] HTML 5 video tag questions
ian at hixie.ch
Mon Jul 27 17:53:59 PDT 2009
There were some proposals to change <video>'s fallback model to allow
markup to be used as an alternative to a video stream, so that once the
various alternative videos had been tried, the user agent would make
<video> act as a regular display:block element and no longer act as a
I haven't changed <video> to do this, for the following reasons:
* We tried this with <object> and we had years of pain. I'm not at all
convinced that we wouldn't have the same problems here again.
* We won't need fallback as soon as we resolve the common codec issue,
which is still being worked on. I don't think we should redesign the
model to address a transient problem in the platform.
* This model would either have to make <video> not dynamic -- once you
fail to load a video, you can no longer use it, because it's showing
fallback -- or would require us to introduce yet more state to keep
track of whether we should be displaying fallback or not.
* If it's not dynamic, we'd have to define what happens when you use the
API when the fallback is being shown. Especially for cases like off-
page <audio>, this would lead to a quite confusing authoring experience.
* We'd need to have an explicit way of triggering the behaviour for
<source>, given the way the media loading algorithm works.
* It's a change, and I really would like to put the brakes on the number
of non-critical changes we make.
When the element was designed, we explicitly didn't do this -- that's why
we have <source>, and is why the fallback is explicitly intended for
legacy user agents, and not user agents that don't support the given
videos. Which is to say, we didn't accidentally stumble into this design.
All in all, I'm very skeptical that this is a good idea.
What's more, any solution would almost certainly involve scripting anyway,
and once you're doing things with script, it's really trivial to do the
fallback manually, especially with all the hooks <video> provides, so the
use cases don't seem that compelling.
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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