This is just a totally fascinating study of modern software. It's fascinating that you have a spec as widely adopted as JFIF/JPEG, and clearly the original engineers did a good job specifying some important meta-data. I'm sure they had all sorts of use cases where this was important.
And yet (a) very little software handles it at all, and (b) those who do get it wrong. When does Software Archeologist become a well-paid job? That would be an interesting thing to be called out of retirement to do some day. :) My guess is Photoshop was the first tool to consider this metadata and got it wrong, and everyone else is copying Photoshop. FWIW, Houdini's "mplay" image/flipbook viewer seems to ignore it too. --jono On Fri, May 20, 2016 at 1:36 AM Kevin Wheatley <[email protected]> wrote: > now I'm at work the best documentation I have is from ITU T.871 which > is ISO/IEC 10918-5: > > Units for the H (horizontal) and V (vertical) densities: > = X'00': units unspecified; H and V densities, expressed in dots per > arbitrary unit, specify only the pixel aspect ratio (width:height > pixel aspect ratio = Vdensity:Hdensity). > > which is more explicit than the JFIF 1.02 de facto standard, which was > what I read last night. JFIF 1.02 I thought could be read in an > ambiguous manner. > > This is much better, but reinforces something I mentioned to some > people yesterday; specifications should come with some form of > examples/reference implementation, especially when tying together > multiple standards or when there are variations supported due to > combining multiple proposals. > > Kevin > _______________________________________________ > Oiio-dev mailing list > [email protected] > http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org >
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