[Theora-dev] aspect ratio ?

[Ralph Giles]

<1089811034.25780.7.camel at x30> <1089813740.25780.13.camel at x30>
Message-ID: <20040714150022.GA386 at ghostscript.com>

On Wed, Jul 14, 2004 at 04:02:20PM +0200, j at thing.net wrote:

> 13. Read a 24-bit unsigned integer as PARN.
> 14. Read a 24-bit unsigned integer as PARD. Together with PARN,
>     these specify the aspect ratio of the pixels within a frame, defined as
>     the ratio of the physical width of a pixel to its physical height. This
>     is given by the ratio PARN : PARD. Either of these fields MAY be
>     zero, in which case the pixel aspect ratio defaults to 1 : 1.

FWIW, I'd rather a value of 0 or */0 indicate 'unknown', as in:

Either of these fields MAY be zero, indicating that the pixel aspect ratio
is 'unknown' and the decoder MAY default to 1:1 or attempt to guess based
on other information available to it.

Perhaps the second MAY should be a SHOULD?

-r