September 2015 - chuck-users - lists.cs.princeton.edu

writing to fifo from chuck
by Forrest Curo 26 Sep '15

26 Sep '15

Something I've been doing from pd: writing a line (or more) of text to a fifo and letting csound read that in as score lines. Trying the same from chuck -- I find that I can write text to a normal file. When I send the same text to a fifo, nothing happens. If I don't close the fifo chuck merely freezes; if I do close it at the end of each line, chuck continues to receive midi notes but csound doesn't get anything from the other end. Do I need to open the fifo in 'WRITE_ONLY mode"? Will try now. Other thoughts?

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Where are details like 'chout' and '<=' documented?
by Forrest Curo 24 Sep '15

24 Sep '15

Searching online I found one example for 'chout' -- which I was able to use, except that I've got no idea what it's doing aside from the fact that I can plug a string I want to send out into that example. And I can't find (so far) documentation that tells me why this example is written the way it is, or even that such syntax is even in the language. Where? -- (Help?!!!)

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sndfilelib for compiling chuck 1.3...
by Forrest Curo 24 Sep '15

24 Sep '15

I've just tried the instructions for compiling/installing chuck 1.3; and these worked exactly as given, on a confuser running ubuntu 15.04. On another, with ubuntu 14.04 -- I find the compilation crashing for lack of "asoundlib.h" Assuming that this is part of the libsndfile listed as a dependency on your download page, I followed the link to http://www.mega-nerd.com/libsndfile/#Download and installed that. However, back in the .... chuck/src directory, I'm still getting: ~/chuck-1.3.5.1/src$ make linux-alsa g++ -I. -Ilo -O3 -D__LINUX_ALSA__ -D__PLATFORM_LINUX__ -O3 -fno-strict-aliasing -D__CK_SNDFILE_NATIVE__ -c RtAudio/RtAudio.cpp -o RtAudio/RtAudio.o RtAudio/RtAudio.cpp:5267:28: fatal error: alsa/asoundlib.h: No such file or directory #include <alsa/asoundlib.h> ------------------------- (?)

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Re: [chuck-users] FFT Convolution and CPU Load
by Perry Cook 23 Sep '15

23 Sep '15

Hum…. Just checked my example and my CPU went from 7% to 11% when I kicked on the FFTConvolve.ck program you cite. We can’t see all your code, so not sure what’s going on. Are you updating really often, like advancing time every sample or something? PRC > On Sep 22, 2015, at 9:00 AM, chuck-users-request(a)lists.cs.princeton.edu wrote: > > // FFT convolution with static impulse response > // by Perry R. Cook, November 2014 > // upsides: as efficient as it could be, save for > // constructing a specific fft convolution chugin > // downsides: minimum delay is length of impulse response + buffers > // fix: break into pieces and overlap add > // Other fix: see filter version using my FIR Filter chugin > > // our fixed convolution kernal (impulse response) > SndBuf s => FFT ffth => blackhole; > "CelloBodyShort.wav" => s.read; // whatever you like (caution of length!!) > 2 => int fftSize; > while (fftSize < s.samples()) > 2 *=> fftSize; // next highest power of two > fftSize => int windowSize; // this is windowsize, only apply to signal blocks > windowSize/2 => int hopSize; // this can any whole fraction of windowsize > 2 *=> fftSize; // zero pad by 2x factor (for convolve) > // our input signal, replace adc with anything you like > adc => Gain input => FFT fftx => blackhole; // input signal > IFFT outy => dac; // our output > fftSize => ffth.size => fftx.size => outy.size; // sizes > Windowing.hann(windowSize) => fftx.window; > // <<< s.samples(), fftSize >>>; > windowSize::samp => now; // load impulse response into h > ffth.upchuck() @=> UAnaBlob H; // spectrum of fixed impulse response > s =< ffth =< blackhole; // don't need impulse resp signal anymore > > complex Z[fftSize/2]; > 1000 => input.gain; // fiddle with this how you like/need > > while (true) { > fftx.upchuck() @=> UAnaBlob X; // spectrum of input signal > > // multiply spectra bin by bin (complex for free!): > for(0 => int i; i < fftSize/2; i++ ) { > fftx.cval(i) * H.cval(i) => Z[i]; > } > outy.transform( Z ); // take ifft > hopSize :: samp => now; // and do it all again > }

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Convolution FFT Performance
by Mitch Kaufman 21 Sep '15

21 Sep '15

Hi List, I was wondering if someone might be able to help with a performance issue I am having with ChucK in respect to the use of FFT/IFFT. I've written a Pulsar Generator and I've added a convolution function to the pulse train of the generator. I found a previous thread that I've used as a basis for the convolution (see the posting below). The main change was to replace the following line: adc => Gain input => FFT fftx => blackhole; with this one: SinOsc sin => WinFuncEnv env => Pan2 pan => Gain input => FFT fftx => blackhole; At rest, the JACK DSP Load is about 2.2%. When I run the Pulsar Generator at a reasonable rate, the DSP Load jumps to about 3.5% or so without convolution. When I add the convolution function as below, it quickly jumps to a 100% usage with steady Xruns. The sample sizes I am using for the SndBuf statement below are somewhere between 18000 and 28000 samples. Is there a strategy anyone could suggest to achieve greater performance of the convolution function below or are there alternative strategies for implementing convolution in general? I'd appreciate any advice. +++ [chuck-users] Daniel: Convolution (FFT version) Perry R Cook prc at CS.Princeton.EDU Tue Nov 25 19:09:31 EST 2014 Previous message: [chuck-users] Daniel: Convolution Next message: [chuck-users] chugins won't compile Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] FFT version. Most efficient, lots of delay. Could chunk up and factor, overlap-add for less delay. This is the basic idea tho. // FFT convolution with static impulse response // by Perry R. Cook, November 2014 // upsides: as efficient as it could be, save for // constructing a specific fft convolution chugin // downsides: minimum delay is length of impulse response + buffers // fix: break into pieces and overlap add // Other fix: see filter version using my FIR Filter chugin // our fixed convolution kernal (impulse response) SndBuf s => FFT ffth => blackhole; "CelloBodyShort.wav" => s.read; // whatever you like (caution of length!!) 2 => int fftSize; while (fftSize < s.samples()) 2 *=> fftSize; // next highest power of two fftSize => int windowSize; // this is windowsize, only apply to signal blocks windowSize/2 => int hopSize; // this can any whole fraction of windowsize 2 *=> fftSize; // zero pad by 2x factor (for convolve) // our input signal, replace adc with anything you like adc => Gain input => FFT fftx => blackhole; // input signal IFFT outy => dac; // our output fftSize => ffth.size => fftx.size => outy.size; // sizes Windowing.hann(windowSize) => fftx.window; // <<< s.samples(), fftSize >>>; windowSize::samp => now; // load impulse response into h ffth.upchuck() @=> UAnaBlob H; // spectrum of fixed impulse response s =< ffth =< blackhole; // don't need impulse resp signal anymore complex Z[fftSize/2]; 1000 => input.gain; // fiddle with this how you like/need while (true) { fftx.upchuck() @=> UAnaBlob X; // spectrum of input signal // multiply spectra bin by bin (complex for free!): for(0 => int i; i < fftSize/2; i++ ) { fftx.cval(i) * H.cval(i) => Z[i]; } outy.transform( Z ); // take ifft hopSize :: samp => now; // and do it all again } Regards, Mitch

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Std.setenv() question
by Scott Smallwood 19 Sep '15

19 Sep '15

Hey Chuckians… Question for those who use Std.setenv(). I’m trying to resurrect some old code of mine that made use of a special environment variable we used to use in plork to identify machines over the network. In short: this was a variable we called “NET_NAME”, in which we specified the network name address (i.e. blah.local) on our local area wireless network. What I’m wondering is this: in UNIX, there is usually a variable already in existence called “HOSTNAME”. For example, on my mac, when I type “echo $HOSTNAME” in the terminal, it returns a string that contains the name of my machine with .local appended to it. However, when I try to recall this variable using Std.setenv(), I get nothing. Anyone have any ideas here? —ss [ - ] Scott Smallwood <http://www.scott-smallwood.com/> - Associate Professor - University of Alberta [ - ]

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miniAudicle alternative
by O L 18 Sep '15

18 Sep '15

Hello all. I have been learning and enjoying ChucK but I'm running into eyestrain issues with the white background of miniAudicle. In the past I have used Sublime text for CSS/HTML with no issue, so ideally I'm looking for something with a dark background. I've seen things referencing using vim or emacs, but I have no idea how to get that up and running. I've searched the list but all the posts I see assume a level of competency with these editors that I don't have. Is there a resource for getting started (on OSX if that matters) from a beginners perspective with ChucK on something other that miniAudicle? Thanks in advance.

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Glisson ChucK Program
by Mitch Kaufman 17 Sep '15

17 Sep '15

Joel, Casper, Thanks very much for your help with this. Regards, Mitch

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Glisson ChucK Program
by Mitch Kaufman 04 Sep '15

04 Sep '15

Hi list, I am a relatively new user and am enjoying exploring different areas of ChucK. I was trying to develop a program to create glissons or short particles with a moving frequency range. I came up with an approach but I think there may be an easier way. Here is the program: SinOsc sin => dac; Envelope env => blackhole; 500.0 => sin.freq => float x; //starting frequency 100::ms => dur rampTime; //ramp time period 0 => env.value; //starting value rampTime => env.duration; 400.0 => env.target; //ramp to target - in this case, 900 Hz now + rampTime => time t; while( now < t ) { // modulate frequency by envelope x+env.value() => sin.freq; // advance time by 100 samples 100::samp => now; } I think there may be an easier way of doing this using: Envelope env => SinOsc sin => dac; But I can't seem to get it working using a proper sin.sync value. Does anyone have any ideas on improving the approach? Regards, Mitch

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