[FFmpeg-devel] [PATCH] Fix for ogg timestamps when packets span multiple ogg pages

Michael Niedermayer michaelni
Sun Nov 9 09:49:00 CET 2008

On Sun, Nov 09, 2008 at 02:48:01AM -0500, David Conrad wrote:
> On Nov 6, 2008, at 5:51 PM, David Conrad wrote:
>> Hi,
>> The problem with the current code comes from how an ogg page with only a 
>> partial packet uses the special granulepos of -1. The granulepos needs to 
>> be saved from the last page that completed a packet until the next page 
>> that completes a packet, where it is the timestamp of the first complete 
>> packet.
> After looking at ogg granule_position some more, there's another problem in 
> that Dirac and ogm both assume that the timestamp is the beginning of the 
> associated packet, wheras Xiph codecs define the granule as the time after 
> the associated packet is fully decoded (I'm assuming, I've only found 
> Vorbis and Theora to do so explicitly.)

older versions of theora also use the ogm variant IIRC
also see the (non working AFAIK) hack in theora_gptopts() about that

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I hate to see young programmers poisoned by the kind of thinking
Ulrich Drepper puts forward since it is simply too narrow -- Roman Shaposhnik
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