On Jul 11, 2009, at 3:34 PM, Philip Jägenstedt wrote:
Not that I except this discussion to go anywhere, but out of
curiosity I checked how Firefox/Safari/Chrome actually implement
canPlayType:
http://wiki.whatwg.org/wiki/Video_type_parameters#Browser_Support
Firefox is conservative and honest (except maybe for "audio/wav;
codecs=0", what could you do with the RIFF DATA chunk?) Safari gets
maybe/probably backwards compared to what the spec suggests. Chrome
seems to ignore the codecs parameter, claiming "probably" even for
bogus codecs. Authors obviously can't trust the distinction between
"maybe" and "probably" to any extent.
Thanks for doing the research. We'd appreciate bug reports on any
Safari/WebKit behavior that seems incorrect, and I'll certainly ask
the Apple folks who work on this to study the matter. Our life is a
little harder than Mozilla's since we use a separate media framework
and support an open-ended set of codecs. But still, we'd like to get
this right.
I think you are probably right that the "maybe"/"probably" distinction
is not currently reliable and likely not relied on in practice. What
we do seem to have is some reliance on the answer being one of "maybe"
or "probably" as indication of a positive result. I don't know the
extent of such reliance but I suspect it will be worse before we can
design, implement and ship a thorough redesign.
One possibility is to consider canPlayType a lost cause as far as
having a really great API, and add a cleaner and better defined API in
parallel. But I'm not sure the improvement would be worth the cost.
Depends on the specifics.
- Maciej
