On Mi, 2007-01-03 at 11:11 +0200, Sergei Steshenko wrote:> On Wed, 03 Jan 2007 09:22:50 +0100> Sebastian Schäfer <schaefer@xxxxxxx> wrote:> > > > [removed stuff]> > > > > > What does the "Speicherzugriffsfehler" word mean ?> > > > > > > "Speicherzugriffsfehler" means segmentation fault - sorry for not> > substituting it.> > Oh, sorry to hear that the segmentation fault is there. But this one> appears to be of a different kind - the previous one in the port connection> routine, and this one is in the run routine.> > Let's continue our debugging with the 'applyplugin' utility.> > What kind of FFTW library do you use ? Is it FFTW2 or FFTW3 ?> > Most importantly, is it SSE or another vector arithmetic enabled one ?> It's FFTW3, but I do not know whether SSE is used as I just installedthe Debian package (from unstable). Its version is: fftw3-3.1.2-1 > The question is important because SSE-enabled FFTW requires proper> alignment of buffers.> > I need answers to these questions in order to be able to correctly reproduce> your setup.> > I tested the plugin before releasing using 'ams', there were no crashes> and, I think, 14 cascaded instances just worked just fine on> Athlon XP1900+ machine.> > > > > > Regarding the> > > > > > "> > > instantiateMChMBEq :INFO: actual 00 band bin number: 2 frequency:> > > 23,4375Hz> > > mbeq_119700: !!! ERROR !!! 28.2842712474619Hz band is too close to> > > previous one (gets into the same FFT bin)> > > mbeq_119700: either change the frequency or increase number of point is> > > FFT> > > "> > > > > > message - it says what it says - you can't have such close frequencies> > > under given conditions.> > > > > > > I thought so, because in the documentation only sample frequencies of> > 44,1 kHz were mentioned, thus I resampled to that frequency.> > I will now try to rewrite as recommended by you.> > But: What will happen when I try to play a file with 96 kHz? I suppose> > then again frequencies would be too close, wouldn't they?> > > > I think some automatism throwing out the closest frequencies would just> > be great - at least for version 2 of the plugin :-)> > There is no way to do this completely automatically, and this is what> README.multichannel_multiband_equalizer.txt file says on the issue:> > "> One of the main issues is DFT/FFT spectral resolution. For N point DFT with> sampling frequency Fs spectral resolution is (Fs / N).> > The plugin the way it is released has N = 4096, so for audio CD sampling> frequency of 44100Hz spectral resolution is (44100 / 4096)Hz = 10.766602Hz.> > The existence of spectral resolution prevents end user from having> arbitrary central band frequencies in DFT-based equalizers, central frequencies> can only be a multiple of spectral resolution.> ".> > That is, if you want the thing to work at 96kHz sampling rate, either> increase N or decrease the equalizer spectral resolution, i.e. have> less bands per octave.> > The problem is that the code is generated before the plugin is called, i.e.> the code is first generated, then compiled, only then the plugin is> called, and sampling frequency becomes known only after the plugin is called.> > In more detail - ALL the control ports MUST be known before compilation,> and once they've been created, they can't be removed.> > There is a mathematical problem with two frequencies falling onto the> same FFT bin (I mean, your "throwing out the closest frequencies" words)> and the problem is division by zero.> > Regards,> Sergei.> > -------------------------------------------------------------------------Take Surveys. Earn Cash. Influence the Future of ITJoin SourceForge.net's Techsay panel and you'll get the chance to share youropinions on IT & business topics through brief surveys - and earn cashhttp://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV_______________________________________________Alsa-user mailing listAlsa-user@xxxxxxxxxxxxxxxxxxxxxxxxxx://lists.sourceforge.net/lists/listinfo/alsa-user
