[whatwg] HTML5 video element - default to fallback in cases where UA can't play format
kornel at geekhood.net
Thu Dec 3 05:31:41 PST 2009
>> Can someone explain to me how this works, given Aryeh's response
>> above? Surely if the iPhone can determine its capacity to be able
>> to play a video file, other UAs could do likewise and fall back on
>> the content accordingly as UAs with zero <video> support do?
> I know nothing about the iPhone, but any UA can know if it can play
> a resource or not simply by trying and adjusting the UI as
> appropriate. One *could* use the same hooks to display fallback
> content in those cases, but it is a very bad idea. Apart from the
> things Aryeh mention, because of how the resource selection
> algorithm works, you can never know if there will be a playable
> resource later, so there's no point where it's appropriate to show
> the fallback content. The only remaining option is flip-flopping
> between replaced content (video) and fallback content, which don't
> want (especially considering that the fallback content is likely to
> contain <object> for Flash or some other legacy fallback).
How about making end of selection algorithm explicit?
Something like video.imDoneWithSourcesEitherPlayOrShowFallback()
method, which upon failure permanently locks <video> in fallback state
(to avoid flip-flopping).
or a special source that, if selected, triggers fallback:
<source fallback> (or <source src="#fallback">?)
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