[whatwg] video tag: pixel aspect ratio
eric.carlson at apple.com
Wed Oct 15 14:48:31 PDT 2008
On Oct 15, 2008, at 1:04 PM, Ralph Giles wrote:
> On Wed, Oct 15, 2008 at 12:31 PM, Sander van Zoest <sander at vanzoest.com
> > wrote:
>> Following that logic, why add the attribute at all?
> Well, I like the pixelaspect attribute because incorrect aspect ratios
> drive me up the wall. Because the video and its embedding page are
> often served from different locations, it's nice to have a way to fix
> it the doesn't require editing the video file.
I agree that incorrectly encoded videos are annoying, but I don't
think we should have this attribute at all because I don't think it
passes the "will it be commonly used" smell test.
I am also afraid that it will difficult to use correctly, since you
frequently have to use clean aperture in conjunction with pixel aspect
ratio to get the correct display size. For example (you probably know
this, but for the benefit of others following the discussion) DV NTSC
video is 720x480, has Rec.601 aspect ratio (10:11), and should be
displayed at 640x480. Multiplying 720x480 by 10:11 doesn't give
640x480 however, you have to crop to clean aperture (704x480) first.
We *definitely* don't want to expose CLASP.
I don't think it should be included in the first version of the spec.
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