[whatwg] video tag: pixel aspect ratio
singer at apple.com
Mon Nov 17 16:36:52 PST 2008
At 23:32 +0100 17/11/08, Philip Jägenstedt wrote:
>I should point out that the pixelratio attribute isn't only for authors,
>it's also useful when the media framework used doesn't recognize the
>(pixel) aspect ratio even when it's correctly set. From reading the
>mplayer man page I see that AVI files can have aspect ratio set in the
>OpenDML vprp header, but I doubt e.g. DirectShow supports this (I could
>be wrong though).
I have a feeling that this is but one of a class
of statements "that the media file could have,
and maybe should have, made" but that it did not.
I wonder if picking them off piece-meal, one by
one is right.
Particularly, obviously, "missing" annotations
come to mind (and this is much more likely than
missing video attributes), where you might indeed
want to author one file in say XML that contains
a whole load of metadata and associate it with
several <source> elements, all of which are
versions (different compressions, bitrates etc.)
of the same conceptual content.
If we're not doing it for this rather more
obvious use, and we're not doing it generally,
why are we doing it for pixelratio?
Another obvious over-ride, which I think also
comes up more often, is when the source doesn't
tag its color space correctly ("It was designed
for traditional Mac gamma and it's now put on the
web and viewed on Windows systems").
Multimedia Standards, Apple Inc.
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