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

   Hi!

On Wed, Sep 27, 2006 at 11:16:27PM +0100, James Courtier-Dutton wrote:
> 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.

I am using the following for testing my resampler code:
 - generate sine signal
 - upsample it
 - generate expected sine signal
 - subtract those two

It only works if you precisely know how much delay the upsampling
introduces, but if you know this, then you can compute the exact maximum
error between these two signals and get a dB error value. If you repeat
the test for many different frequencies, you can plot how your resampler
performs at different frequencies.

   Cu... Stefan

-- 
Stefan Westerfeld, Hamburg/Germany, http://space.twc.de/~stefan