[whatwg] Scripted querying of <video> capabilities
eric.carlson at apple.com
Thu Nov 13 11:19:07 PST 2008
On Nov 13, 2008, at 10:52 AM, Jeremy Doig wrote:
> did this thread go anywhere ?
> i'm concerned about the "maybe" case - looks way too much like:
> also - when you probe for mime type, do you mean the entire "type"
> parameter (including the codecs string) ? for example, there are too
> many cases where just passing "video/mp4" would be insufficient.
> (fragmented index support ? base/main/high profile ? paff ? cabac ?)
> <source src="video.mp4" type="video/mp4; codecs="avc1.42E01E,
My interpretation is that it does, and the vagueness of many MIME
types is the reason for the "maybe" case.
> On Wed, Oct 15, 2008 at 11:14 PM, Maciej Stachowiak <mjs at apple.com>
> On Oct 15, 2008, at 1:44 AM, Ian Hickson wrote:
> On Tue, 14 Oct 2008, Robert O'Callahan wrote:
> On Tue, Oct 14, 2008 at 12:13 PM, Maciej Stachowiak <mjs at apple.com>
> While the underlying media frameworks can't necessarily answer, "if I
> give you a file with this MIME type, can you play it?", they can at
> least give a yes/no/maybe answer, which can still be quite helpful,
> since the UA will know it does not need to check some media streams at
> I agree. If the API lets us answer "maybe", there is not much need or
> temptation to lie, and we can still return information that could be
> useful to scripts.
> I have added window.navigator.canPlayType(mimeType). It returns 1,
> 0, or
> -1 to represent positive, neutral, and negative responses.
> This API would be tempting to treat as a boolean but would of course
> do completely the wrong thing. I think it would be better to either
> ensure that the positive and neutral responses are both values that
> JS would treat as true (for instance make the values true, "maybe"
> and false), or else make all of the return values something self-
> descriptive and symbolic (for instance the strings "yes", "maybe"
> and "no"). I think 1, 0, -1 are neither clear nor likely to be in
> any way beneficial for perforamnce.
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