[theora] Indexing Ogg files for faster seeking

Chris Pearce chris at pearce.org.nz
Tue Oct 13 15:24:39 PDT 2009

On 10/14/2009 9:49 AM, j at v2v.cc wrote:
>> 10mins of video takes about 11KB to index, depending on the video.
> how big would it be if the index would be lets say gziped?

Interesting idea. :)

However, gzipping the index makes it harder to do the indexing/encoding 
in one pass, which was a concern some people raised. The idea is that 
during encoding, you allocate space at the start of the media for the 
index, and you then fill it with the index. You can do this, as you can 
choose the granularity of the index you want, and that exactly 
determines its size. If you gzip the index, you don't in advance what 
its final size will be. If you underestimate, you've got to rewrite the 
file to fit the index, if you overestimate you waste space (though you 
may save space overall).

I don't personally have a problem with rewriting the entire file again, 
my current Indexer does this, but some people complained about it.

Chris P.

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