W3C home > Mailing lists > Public > public-media-capture@w3.org > August 2014

Re: [Bug 26526] Fix aspect ratio constraint

From: Harald Alvestrand <harald@alvestrand.no>
Date: Wed, 13 Aug 2014 08:49:32 +0200
Message-ID: <53EB0A7C.3030903@alvestrand.no>
To: public-media-capture@w3.org
On 08/12/2014 06:17 PM, Jan-Ivar Bruaroey wrote:
> On 8/11/14 6:17 PM, Martin Thomson wrote:
>> On 11 August 2014 14:34, Jan-Ivar Bruaroey <jib@mozilla.com> wrote:
>>> Actually, the spec already says: "The exact aspect ratio (width in 
>>> pixels
>>> divided by height in pixels), represented as a double rounded to the 
>>> tenth
>>> decimal place" [1]
>>>
>>> So we effectively have our epsilon already: .0000000001
>>>
>>> So no action required it seems.
>> Oh, that's good, there's an epsilon; but it's bad.  1.777777778 isn't
>> the same as 16/9 based on that.  Nor is 1.7777777777.  Add a single
>> digit to either and it would match.  I may have counted wrong. I'm
>> sure that others will too.
>
> Feel free to propose a different epsilon I suppose.
>
> I presume this would have nothing to do with inaccuracies inherent in 
> floating-point math then (or we could have picked an epsilon much 
> closer to everyone's worst machine epsilon), but instead from a desire 
> to accommodate people handwriting rounded decimal numbers for aspect. 
> Just so we're clear on the properties we seek.

I'll repeat my suggestion of an epsilon of 1/1000.

>
> .: Jan-Ivar :.
>
>
Received on Wednesday, 13 August 2014 06:50:04 UTC

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