[linux-audio-dev] How to test resampling quality?

Erik de Castro Lopo mle+la at mega-nerd.com
Wed Sep 27 22:46:53 UTC 2006

James Courtier-Dutton wrote:

> Hi,
> I was wondering if there are any tools out there to test audio
> resampling quality. I am particularly interested in 44.1kHz to 48kHz
> resampling due to the fact that most sound cards prefer 48kHz.
> At least with up sampling (low rate to higher rate) one does not get
> aliasing.

Err, sorry, aliasing can also be produced during up sampling; in
particular, aliasing can be created in the fs/2 to fd/2 band where
fs is the source sample rate and fd is the desitination sample rate.

> I really just want to find some algorithm that I can use to compare
> 44.1kHz audio signal with an 48kHz audio signal, and to see if there has
> been any lose of quality during the up sample.

The Secret Rabbit Code test suite has some pretty extensive SRC
test code. YOu can get the Rabbit here:


and I gave a bit of a talk about this stuff at an LCA minconf in
2005. The slides are here:


  Erik de Castro Lopo
Journalist: Microsoft CEO Steve Ballmer has finally said Linux
            is the No. 1 threat to Windows. What's your response to that?
Linus     : "Tag, you're it." I don't care. They've had a lot of
            enemies in their time. Let them fight one enemy that
            doesn't care for a change.

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