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

Re: [Bug 26526] Fix aspect ratio constraint

From: Jan-Ivar Bruaroey <jib@mozilla.com>
Date: Tue, 12 Aug 2014 12:17:30 -0400
Message-ID: <53EA3E1A.4010805@mozilla.com>
To: Martin Thomson <martin.thomson@gmail.com>
CC: Silvia Pfeiffer <silviapfeiffer1@gmail.com>, Eric Rescorla <ekr@rtfm.com>, "public-media-capture@w3.org" <public-media-capture@w3.org>, "bugzilla@jessica.w3.org" <bugzilla@jessica.w3.org>
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.

.: Jan-Ivar :.
Received on Tuesday, 12 August 2014 16:17:59 UTC

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