[whatwg] video tag: pixel aspect ratio

[Dave Singer]

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").
-- 
David Singer
Multimedia Standards, Apple Inc.