[Theora-dev] Problems with Theora alpha 4 crashing

Ralph Giles giles at xiph.org
Sun May 1 13:56:33 PDT 2005

On Sun, May 01, 2005 at 01:08:07PM +0100, Rob Smith wrote:

> I havent posted to this list before, so "hi"


> I traced the fault to being in the "RegulateQ" function, and is
> because YUVAnalyseFrame() returns 0 for the motion score.
> With VP3 I was able to resolve this by changing this value to 1 if
> this happened and that seemed to work fine.

Aha, thanks for pointing this out. Clamping the UpdateScore to 1 is a 
reasonable approach. I don't actually get a floating point exception, 
it's just that the target bitrate gets calculated as infinity.

Derf committed a change to just not update Q if the Score is zero. 
Hopefully this will help with some of popping artefacts we've been 


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