On Wed, 26 Mar 2008 15:57:51 -0700 (PDT) Bill Unruh <unruh@xxxxxxxxxxxxxx> wrote: > On Wed, 26 Mar 2008, Helge Fredriksen wrote: > > > Ok, here's what I found out: > > > > Since these cards seem to lack the support for doing frequency conversion in > > HW, you simply need to use the alsa plugin > > plughw instead of hw when referring to the card: > > > > arecord -Dplughw:0 test.wav > > aplay -Dplughw:0 test.wav > > AFAIK, alsa frequency conversion is pretty primative ( linear > interpolation) which produces a huge amount of noise/distortion. > See www.theory.physics.ubc.a/soundcard/resample.html for a comparison of > various rate conversion routines on a sound sample roughly similar to real > music I'm wondering how polynomial (2-nd, 3-d, 4-th order) interpolation/resampling compares to, say, polyphase one. Polynomial interpolation, requires several samples - polynomial order plus one, so it might acceptable from the point of view latency. Thanks, Sergei. ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
