[vlc-devel] Large ogg packets

Rémi Denis-Courmont rem at videolan.org
Fri Dec 26 10:33:54 CET 2008

Le jeudi 25 décembre 2008, ogg.k.ogg.k at googlemail.com a écrit :
> the Ogg related code that builds/extracts headers in extra data
> stores 2 bytes' worth of the packet size, so this means large ogg
> packets will be mishandled (eg, a 64 KB packet will be seen as
> a 0 bytes packet when 'decoded').
> Is there a particular reason why this is so, or just because 64 KB
> ought to be enough for everybody ? :)
> Id there any gotcha I should know about before I try to change this ?

This is a convention between all codec, demux, mux, etc. plugins which 
uses the extra data for the affected codec(s) (at least Vorbis, I don't 
know Speex and Theora). You need to change any code path that 
recognizes them.

Note that the "raw" mux copies the extra data at the beginning of the 
file, so it makes sense to use some kind of file format. I don't know 
if this works in _any_ circumstances for Xiph payloads. I assume Gildas 
created the current VLC convention for Ogg packets.

In any case, the extra data MUST be serialized (NO pointers).

Rémi Denis-Courmont

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