On Sun, Jul 26, 2009 at 09:15:20PM -0500, Gabriel M. Beddingfield wrote: > On Sat, 25 Jul 2009, Justin Smith wrote: > >> > >> I am using the fftw3 library to implement a transform in a array of 5120 > >> elements . > >> I have this array from a program that I created modifying the arecord > >> program. > [snip] > > > > I don't know fftw specifically, but I am fairly certain that you need > > a table size that is an even power of two for fft in general (maybe > > you can adjust your code to use 4096 or 8192?). > > Ditto that. > > If your data is 5120 samples... either truncate it to 4096 samples or pad > it with zeros util you have 8192 samples.
FFTW3 can handle almost any size you want. If the size has a large prime factor the transform may be significantly slower, but for something like 5120 = 5 * 2^10 the speed loss will be quite moderate. > (The zeros won't affect your transform.) They do affect it but in many cases not in a way that matters to your application. Depends on the app. Ciao, -- FA Io lo dico sempre: l'Italia รจ troppo stretta e lunga. _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
