[theora] Fwd: [show-in-a-box] Re: Ogg

Ralph Giles giles at xiph.org
Sun Aug 19 17:17:12 PDT 2007

On Sun, Aug 19, 2007 at 03:11:40PM -0700, Charles Iliya Krempeaux wrote:

> (Note... they're calling the Theora codec "Ogg" below.  I know
> technically it's not correct... but that's what some are calling it.)

There are a number of confusions. Theora is a keyframe-based codec, as 
are h.263 and On2's VP6, the two codecs supported by Adobe's flash 
player. None of these can be cut losslessly outside of keyframe 

A good editor (or clip trimmer) will do minimal re-encoding on such 
streams, just as it will on other modifications requiring re-encoding,
like transitions and effects. A cruder solution is just to transcode
the entire stream to all-keyframes, either in the same format or a 
different one (like dv or mjpeg). This greatly increases the storage
requirements, which is why the trade-off of editability for keyframe-
based compression was made in the first place.

So, Theora (in the Ogg container) is no more or less editable than 


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