[theora-dev] first keyframe number ?

Ralph Giles giles at xiph.org
Mon Nov 10 23:25:26 PST 2008

On 10-Nov-08, at 8:08 PM, salsaman wrote:

> what is the number of the first *real* keyframe/frame in a theora  
> stream ? Is it 0 or 1 ?

The first frame of the stream (if it hasn't been trimmed) is a  
keyframe. It is displayed between time = 0 and time = 1 * frame_rate.  
The granulepos for that frame is based on the count of frames after  
it's been shown, which is 1, not zero. The only Ogg pages in a theora  
stream with a 0 granulepos should be the headers.


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