[XviD-devel] [CVS commits] decoder speedups and fixed cbr

Bryan Mayland bmayland at leoninedev.com
Wed Aug 11 16:42:36 CEST 2004


Edouard Gomez wrote:

>So feedback is welcome for:
> - decoding speed between 1.0.1 and HEAD CVS. Here i have an
>   average 25% better performance, how is it doing on your
>   box?
>  
>
    Is there a better way to quantifiably test this instead of just 
playing an AVI and watching the task manager?

> - test CBR/ABR coding, just to make sure Foxer (and I, his
>   tester) didn't miss something important.
>  
>
    I've run some tests on 320x240 15fps source content, 900 frames, 
Constant Q=1 2310 kbps,
XVID 1.0.1, 2 max consecutive BVOPs
Target  1-Pass  2-Pass
300     247     263
700     570     699
1000    831     998
2000    1408    1651

XVID 1.0.1, Bframes disabled
Target  1-Pass
700     700   
1000    998
2000    1838

XVID HEAD, 2 max consecutive BVOPs
Target  1-Pass  2-Pass
300     288     263
700     665     701
1000    936     997
2000    1512    1656

Common Options:
H.263 quantizer
Motion Search Precision - 6
VHQ Mode - 1
Chroma Motion Estimation - Enabled
All quantizers set 1-31

I've also looked at every resultant video and they all look as 
expected.  Something that I thought was odd was that using constant 
quantizer=1 that I and P frames used Q=1 but B frames used Q=2.  Not 
that it makes any difference at that bitrate, but is that intended behavior?

Let me know if there's other tests you'd like me to run.
Bry


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