[ogg-dev] non-decreasing granulepos

xiphmont at xiph.org xiphmont at xiph.org
Tue Feb 19 02:40:51 PST 2008

On Feb 19, 2008 5:31 AM, Conrad Parker <conrad at metadecks.org> wrote:

>   * The seeking algorithm suggested in the (troublesome) email quoted at
> http://wiki.xiph.org/index.php/GranulePosAndSeeking is "find the
> earliest page with a granulepos less than but closest to 'x'" should
> be able to handle equal granulepos (if the earliest of a sequence of
> pages with equal granulepos is taken to be the first of those in the
> stream).

Correct.  Actually, the algo I had in mind was 'granulepos with a
mapped time less than but closest to', but that requires the
no-continued packets fix.

>   * The draft mapping for Ogg Dirac uses successive equal granulepos,
> as the packets occur in coded order, not display order:
> http://wiki.xiph.org/index.php/OggDirac#Granulepos
> This is consistent with the definition of granulepos as the "count of
> decodable frames".


> I suggest we clarify that the granulepos of successive pages is
> allowed to be equal, as this is non-obvious from the available
> documentation.
> Thoughts?

Full agreement.


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