[pulseaudio-discuss] Fwd: Pulse Audio Sample Cache & resampling

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Wed Feb 14 20:04:18 PST 2007


> The speex resampler also doesn't match SRC fastest in terms of quality.
> I've got some preliminary spectrograms here:
> 
>     http://www.mega-nerd.com/tmp/SRC_best_sinc.png
>     http://www.mega-nerd.com/tmp/SRC_medium_sinc.png
>     http://www.mega-nerd.com/tmp/SRC_fastest_sinc.png
>     http://www.mega-nerd.com/tmp/speex_resampled.png
> 
> An explanation of how these plots are generated is here:

Problem identified... Turns out it was a really stupid error that caused
the window function to be severely truncated. The aliasing lines are now
down to about -130 dB (on a similar chirp) and the "noise floor" is
around -140 dB (still using single precision, no double yet). Would you
mind re-generating the graph for the latest svn version?

Thanks,

	Jean-Marc



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