Click here to download fourier.zip (14 kb).
To install the plugin, unzip the files into your Winamp plugins directory. If you want a Winamp Pimp .exe file, you will have to get it from the Winamp website. The plugin contains two modules as described below.
Winamp used to provide a Pitch/Tempo control in it's earlier versions. I was rather disappointed when I did not find it in the last version I installed. Then I remembered it was there in the SDK tutorial, and I thought I would just compile it for myself. I started to play with the code, and ultimately added ability to transform pitch or tempo independently, using a mathematical magic called Fourier Transformation.
The module actually contains two subroutines - one for changing the pitch independent of tempo (which actually uses the Fourier Transformation), and one for changing the tempo keeping the pitch/tempo ratio constant. Sometimes one or both of the subroutines may not be necessary. Then they will be turned off automatically, and a star (*) will appear beside the name.
You can mimic the Nullsoft Pitch/Tempo control by fixing the Pitch/Tempo ratio at 1.
Note: If you want to do fourier transformations by the book in a program it is going to be much too slow. Fortunately, there is an ingenious algorithm (or rather, collection of algorithms) available, called the Fast Fourier Transform (FFT). This is what is used in this plugin. The credit for the FFT source goes to Don Cross <dcross@intersrv.com> - thanks Don.
This module provides Reverbed Echo and Chorus. I wrote this plugin long back (01/01/2000) just to get myself aquainted with writing a .dll for the first time.
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