Re: video: various width/height attributes

On Tue, 2 Dec 2008, Jim Jewett wrote:
> 
> At first, I was thinking that simply listing them all in one place (so I 
> wouldn't have to wonder if I had missed one) would help, and that one of 
> the two definitions should be chosen for the "adjusted X" attributes.
> 
> When I look now, I can't find the "adjusted X" attributes at all, so I 
> *hope* this means you already streamlined the wording.

Yeah, they went away with pixelRatio.


> If I understand correctly now, "width" and "height" are the attributes 
> from the document.  They can be modified by a script.  They indicate the 
> actual size on the screen.
> 
> "videoWidth" and "videoHeight" represent the ideal size on the screen. 
> They are how big the video thinks it should be.  These numbers are 
> immutable, as they represent a known transformation based on data from 
> the video itself.  They are also called "intrinsic width" and "intrinsic 
> height".

I believe that's right.


> (Why two names that must both be defined for the same concent?)

videoWidth and videoHeight are DOM attributes; opaque names whose values 
come from other thigns, in this case "intrinsic width" and "instrinsic 
height", which are CSS terms that need to be defined for the rendering to 
be well-defined.


> But I'm not sure how well "intrinsic width" and "intrinsic height" are 
> really defined, because they are "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.."
> 
> Is there some way to figure out which adjustments need to be made in 
> general, or is this a per-codec judgment call of some sort?

My understanding is that it depends on complicated per-codec things.


Is the text ok as-is? I'm happy to try to clarify it more if that would 
help.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
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Received on Friday, 20 February 2009 10:45:16 UTC