[mad-dev] imdct36 CPU usage increase

[Rob Leslie]

On Feb 18, 2004, at 3:23 AM, Derk-Jan Hartman wrote:
> i configured mad to be as fast as possible and still it's twice as 
> intensive as in the older release.
> I'm working with profiling data here, so it's a bit hard to detect the 
> problem. However...
> Though imdct36 is taking the most time by far, I noticed that the 
> difference is within III_decode()
> III_decode takes almost the same CPU time in both versions. however 
> then the differences start.
>
> III_imdct_l takes 2.7% in old version and 7.8% in the new version. 
> That imdct36() is called more often because of this is logical of 
> course. So the problem is probably somewhere within III_decode() and 
> causing III_imdct_l to be called more often than before...
> Any new ideas after this information?

Are you decoding the same bitstream for comparison?

The number of times III_imdct_l() is called depends on the signal being 
decoded. It may not be called at all in the case of short blocks, or it 
may be called only a few times, or several. It varies with the 
complexity of the signal.

If you are using the same bitstream, is the decoded output identical?

-- 
Rob Leslie
rob@mars.org