[whatwg] Scripted querying of <video> capabilities

[Dave Singer]

I think this is a good idea, but one rapidly runs into the problems 
talked about in the 'bucket' RFC, notably that there is not a 
universal language for naming codecs (4ccs etc).  But it's proved 
useful in the past.

In general, the source fallbacks are also a way to 'probe' this, 
albeit in a very different way.

I'm not sure you can always get a definitive answer to the question 
"if I gave you a file with this (extended) MIME type, could you play 
it?" and I am fairly sure that asking the implementation to enumerate 
all the types it could support would be hard.

But this kind of query is really useful on a 'portal' page -- entry 
points to sites.  A script can detect that you need to download oh, 
say, Theora, in order to see the videos in the rest of the site, and 
shows a frame or page that would help you load it. :-)
-- 
David Singer
Apple/QuickTime