[whatwg] Serving up Theora <video> in the real world

Philip Jägenstedt philipj at opera.com
Sat Jul 11 15:34:31 PDT 2009

On Sat, 11 Jul 2009 21:15:47 +0200, Maciej Stachowiak <mjs at apple.com>  

> On Jul 11, 2009, at 7:56 AM, Ian Fette (イアンフェッティ) wrote:
>> 2009/7/11 Robert O'Callahan <robert at ocallahan.org>
>> On Sat, Jul 11, 2009 at 9:38 PM, Philip Jägenstedt
>> <philipj at opera.com> wrote:
>> Well I disagree of course, because having canPlayType("video/ogg")
>> mean anything else than "can I demux Ogg streams" is pointless.
>> So you want "canPlayType" to mean one thing when provided a type
>> without codecs, and another thing when provided a type with codecs.
>> I don't think that's a good idea.
>> Anyway, it's too late. If you care passionately about this you
>> should have reopened this discussion months ago, not now that two
>> browsers have just shipped support for the API in the spec.
>> Disagree -- the whole point of candidate rec (which the spec is
>> driving towards) is to find out how implementable the spec is -- not
>> just from the browser side, but from a web author side as well. If a
>> feature turns out to not be implementable /  usable in practice,
>> that is certainly valid feedback at this stage.
>> (Not to say it wouldn't be better to have had this conversation
>> earlier, but I definitely don't think that the ship has sailed on
>> this, and in practice some things you only find out once it's
>> implemented and you can actually try using it.)
> At this point, I think <video> should only be changed incompatibly if
> it is discovered to be literally unimplementable (unlikely now that
> it's been implemented twice) or unusable for its desired use cases,
> and an incompatible break is the only fix. But I don't think the issue
> at hand is that serious - we're just talking about potential
> refinement. The design we have now for canPlayType is not my favorite,
> but I can't really say it's broken.

Not that I except this discussion to go anywhere, but out of curiosity I  
checked how Firefox/Safari/Chrome actually implement canPlayType:


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.

Philip Jägenstedt
Core Developer
Opera Software

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