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Re: video size when aspect ratio is not 1

From: Philip Jägenstedt <philipj@opera.com>
Date: Thu, 03 Sep 2009 14:04:37 +0200
To: "Ian Hickson" <ian@hixie.ch>, "Simon Pieters" <simonp@opera.com>
Cc: "public-html@w3.org" <public-html@w3.org>
Message-ID: <op.uzojtzxdatwj1d@sisko.linkoping.osa>
On Thu, 03 Sep 2009 13:47:41 +0200, Ian Hickson <ian@hixie.ch> wrote:

> On Mon, 31 Aug 2009, Simon Pieters wrote:
>> On Sun, 30 Aug 2009 23:39:51 +0200, Ian Hickson <ian@hixie.ch> wrote:
>> > On Fri, 21 Aug 2009, Simon Pieters wrote:
>> > >
>> > > The spec should say how a video is to be sized when the video's
>> > > aspect ratio is not 1. It should say to adjust the width of the
>> > > video when aspect ratio is greater than 1, and adjust the height
>> > > when it is less than 1 (i.e. the video should always be scaled up).
>> >
>> > Done.
>>
>> Your change fixed something other than what I had in mind.
>>
>> The following paragraph:
>>
>> "The intrinsic width and intrinsic height of the media resource are the
>> dimensions of the resource in CSS pixels after taking into account the
>> resource's dimensions, aspect ratio, clean aperture, resolution, and so
>> forth, as defined for the format used by the resource."
>>
>> ...doesn't say whether to scale up or down when taking into account
>> aspect ratio.
>
> Wouldn't that be up to the video format?

No, video formats only give the size in pixels and the pixel aspect ratio  
(or alternatively frame aspect ratio). The only constraint is that the  
aspect ratio be correct, which forces us to choose how to achieve that.  
Assuming one dimension remains unchanged:

1. always scale up
2. always scale down
3. always scale x-dimension
4. always scale y-dimension

We're suggesting #1. From the rest I've only seen #3 used in actual media  
players.

-- 
Philip Jägenstedt
Core Developer
Opera Software
Received on Thursday, 3 September 2009 12:05:24 UTC

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