[theora] Indexing Ogg files for faster seeking

Chris Pearce chris at pearce.org.nz
Tue Oct 13 19:18:47 PDT 2009

On 10/14/2009 12:18 PM, Silvia Pfeiffer wrote:
> I have seen the need in professional video applications where the
> beginning of the file is mapped to a time that is not 0.

That could use useful.

>> What software out there currently reads the skeleton?
> I think lots of software skips it, which you could call "basic
> support".

Robust players should skip tracks that they don't understand.

>> I'm also concerned that any players which actually read the skeleton
>> will be crashy. I'll mock up some Oggs with indexes in the skeleton, and
>> see how players handle them.
> Make sure to include the index in a way that is backwards compatible.
> And then if some players crash, they are actual bugs.

Of the proposed index-in-skeleton suggestions, the most palatable is 
Conrad's suggestion of including separate index packets, but it looks 
like liboggplay at least assumes that all skeleton packets which don't 
have 'fishead\0' magic bytes at their start are fisbone packets. So at 
least anything that uses liboggplay *could* break. A robust skeleton 
decoder should check the magic bytes.

Chris P.

More information about the theora mailing list