[vorbis] Ogg Vorbis Quality Analisis (+ bug) (+ misc)

[Jonathan Ingram]

> But the blue line sometimes goes _down_ from one -q to the next. Meaning
> that Vorbis at -q X used _fewer_ bits than Vorbis at -q (X - 0.5). Is
> that not strange? Is it not reasonable to expect that any given q value
> will always use at least as many bits as any lower q value? How can
> higher quality require fewer bits?

You can get a much better idea of what is going on as you vary quality by
looking at the graphs I generated, which use a step size of 0.02 instead of
0.5:

The overall group graph is at:
http://www.maths.warwick.ac.uk/~jingram/ogg/group.png
Data, information, graphs for individual samples, and programs used are in:
http://www.maths.warwick.ac.uk/~jingram/ogg/

You'll see that there are many places where the bitrates are not strictly
increasing - in particular between x.99 and (x+1).00 (except for the 4.99-5.00
transition, which has been explained before).


-- 
Jon

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