June 2006 - chuck-users - lists.cs.princeton.edu

keeping stereo files as stereo
by eduard aylon 19 Jun '06

19 Jun '06

Hello there, When loading a stereo audio file either via sndbuf or WvIn the audio is downmixed to mono automatically, is that right? If not, is there a way of accessing left/right channels from audio files? is there a way of reading stereo files while keeping them stereo and writing them back as stereo files? The following code will write a mono file in out.wav regardless the input file is stereo or mono: WvIn audio_in => WvOut audio_out => blackhole; audio_in.path( "stereo_file.wav"); audio_out.wavFilename("out.wav"); 10::second => now My second question is on regards to being able to process audio faster than realtime just for audio processing tasks and when no "audible" output is needed. Is it possible or will it be possible in the future? An example will probably be more explanatory. Let's say that you want to remove DC-offset from an audio file, but you just want to process the audio file and there's no need to listening realtime audio. If such audio file is 3 min long, one must wait 3 min in order to finish processing. Chuck has a strong sense of time, but if there are no connections to dac could a "time_less unit of time" be created in order to speed up? My apologies if these issues have been discussed earlier on the list. Thanks, eduard

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events and static data
by Atte André Jensen 19 Jun '06

19 Jun '06

Hi If I do "chuck time.ck" then "chuck + shaker.ck" I hear the shaker ticking along after a while. If I then do "chuck + change_bpm.ck" the time is speeded up but the shaker goes silent. 1) Why does it take a while before the first shaker is played, and why isn't it always the same amount of time? 2) Why does the shaker stop playing when I update the bpm? As you might guess I suspect this to be something with static data. I know "static" means "static" so if they can't be updated like this, would the way to go be to send the bpm update as yet another event? -- peace, love & harmony Atte http://www.atte.dk | quartet: http://www.anagrammer.dk http://www.atte.dk/gps | compositions: http://www.atte.dk/compositions public class Time { int bpm; static dur quarter; static dur eight; static dur sixteenth; static Event q; 10 => bpm; fun void setTime() { 1::minute/this.bpm => this.quarter; this.quarter/2 => this.eight; this.quarter/4 => this.sixteenth; } fun void sendTime() { while(true){ this.q.broadcast(); <<<"q.broadcast", now>>>; this.quarter => now; } } } Time T; 80 => T.bpm; T.setTime(); T.sendTime(); Time T; 4::T.quarter - (now % 4::T.quarter) => now; Shakers inst => dac; [0,2,3,1,4,2,6,3,4,4] @=> int mel[]; for (0=>int i; ; i++) { <<<"shaker">>>; std.mtof( 60 + mel[i%mel.cap()] ) => inst.freq; inst.noteOn( 0.5 ); T.q => now; } Time T; 200 => T.bpm; T.setTime();

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getting the current srate
by Atte André Jensen 18 Jun '06

18 Jun '06

Hi I'm in the process of making a small bpm calculator, as part of a bigger whole. It detects taps on a midikey and calculates the bpm from the distance between the taps. What it boils down to is that I end up with a duration, which at 60 bpm (and tight tapping) is 47904.000000 and if I run with --srate44100 is 44096.000000. Looks to me like time is counted in samples, right? Anyways, if my algorithm should work at all sample rates, I need to ask from within chuck what sample rate we're running at. How is this done? -- peace, love & harmony Atte http://www.atte.dk | quartet: http://www.anagrammer.dk http://www.atte.dk/gps | compositions: http://www.atte.dk/compositions

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sporking a member function
by Atte André Jensen 18 Jun '06

18 Jun '06

Hi I had a problem last year with chuck crashing (null pointer exception, if I recall correctly) when trying to spork a member function from another function in a class. I forgot which version this was, but the problem is still there. Any chance this could be fixed in a/the new version? -- peace, love & harmony Atte http://www.atte.dk | quartet: http://www.anagrammer.dk http://www.atte.dk/gps | compositions: http://www.atte.dk/compositions

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Question on Shred Scheduling
by Mike McGonagle 17 Jun '06

17 Jun '06

I am working on a complete rewrite of my Masking package (the original was too bulky and dependant on creating hundreds of shreds), and was wondering just how something is scheduled in ChucK. Basically, I am trying to create a single shred that handles the updating of various parameters (as opposed to the original which had a shred for each parameter), and in doing so, I would like to create a "locking" mechanism around an array used to control which parameters get updated, and when. On one shred, there is the code that controlls the updating of parameters, this shred runs for the life of the program (or some portion of). On the second shred (most likely the main shred), the array containing the references to the parameters to be updated needs to be locked to prevent having a new reference added while the first shred is actually updating the parameters. (Does this make sense?) So, what I would like to know is how the following code would execute. now + 0::ms => now; Would this push the execution of the code to follow to the end of the current time slice? Or is this functionality undefined, and would it execute these shreds in an arbitrary fashion? In a nut shell, this is the code from the updating shred that locks the array... (this is embedded in an object) false => int locked; false => int keepGoing; MController @ controllers[]; // this gets initialized to match the number of controlled parameters fun void helper(....) { true => keepGoing; while(keepGoing) { while(locked) { now + 0::ms => now; } true => locked; for(0 => int i; i < controllers.cap(); i++) { if (controllers[i] != null) { <<< "do something with this controller", "" >>>; } } false => locked; } } The variable 'locked' controlls the access to the 'for' loop, and the variable 'keepGoing' controlls the outer loop. 'keepGoing' is set to true at the top of this code, but will be set to false by another shred to force the 'helper' function to exit as needed. The array 'controllers' is accessed by both this shred, as well as the main shred to add extra parameters to the 'helper' shred. Wow, this was probably a roundabout way to ask this question, but I hope it is comprehensible... Thanks, Mike -- Help the Environment, Plant a Bush back in Texas!

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Strings
by Ollie Glass 16 Jun '06

16 Jun '06

I'm trying to print this xml string from chuck: <step step="3" cycle="0" > What I get, when I use this code: <<< "<step step=\"", step ,"\" cycle=\"", cycle, "\" >" >>>; is this: <step step=\" 3 \" cycle=\" 0 \" > Spaces and escape characters abound! Could someone help me with this? Cheers, Ollie

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Re: [chuck-users] user study!!!
by biotechisgodzilla.wifebeater 15 Jun '06

15 Jun '06

This is in merit of the great tutorial at http://ravelite.org/chuck-notes/tutorial.html there is a little typo here: Now use this function to simulate indexing into the scale. [0,2,3,1,4,2,6,3,4,4] @=> int mel[]; //sequence data [0,2,4,5,7,9,11,12] @=> int major[]; //major scale for (0=>int i; ; i++) { //infinite loop std.mtof( 48 + scale( mel[i%mel.cap()], major ) => inst.freq; //set the note inst.noteOn( 0.5 ); //play a note at half volume 300::ms => now; //compute audio for 0.3 sec } this string: std.mtof( 48 + scale( mel[i%mel.cap()], major ) => inst.freq; //set the note lacks an ) should be std.mtof( 48 + scale( mel[i%mel.cap()], major )) => inst.freq; //set the note seeya .mike

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problem with chuck-notes tutorial
by Atte André Jensen 15 Jun '06

15 Jun '06

Hi I'm having a problem with the "chuck-notes" tutorial (http://ravelite.org/chuck-notes/tutorial.html). In section 1.3 (Flexible scales) I pasted the examples into the attached file, with which chuck reports: [atte@aarhus chuck-notes]$ chuck tut_04.ck [tut_04.ck]:line(24).char(64): syntax error Am I missing something obvious here? -- peace, love & harmony Atte http://www.atte.dk | quartet: http://www.anagrammer.dk http://www.atte.dk/gps | compositions: http://www.atte.dk/compositions //connect a plucked string to the soundcard out StifKarp inst => dac; fun int scale(int a, int sc[]) { sc.cap() => int n; //number of degrees in scale a/n => int o; //octave being requested, number of wraps a%n => a; //wrap the note within first octave if ( a<0 ) { //cover the negative border case a + 12 => a; o - 1 => o; } //each octave contributes 12 semitones, plus the scale return o*12 + sc[a]; } [0,2,3,1,4,2,6,3,4,4] @=> int mel[]; //sequence data [0,2,4,5,7,9,11,12] @=> int major[]; //major scale for (0=>int i; ; i++) { //infinite loop std.mtof( 48 + scale( mel[i%mel.cap()], major ) => inst.freq; //set the note inst.noteOn( 0.5 ); //play a note at half volume 300::ms => now; //compute audio for 0.3 sec }

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Atlanta Laptop Battle: Mon 11 June 10ish - Lenny's
by Graham Coleman 15 Jun '06

15 Jun '06

ChucKers (who may or may not be in Atlanta), I'll be competing in Battle Three of the Series. I'll be spinning some live ChucK. It might be silly. But that isn't going to stop me. more information: http://www.zeroplate.com/laptop/ best, Graham

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Re: [chuck-users] MidiOut
by Ollie Glass 13 Jun '06

13 Jun '06

Thanks for the example, that's perfect. I guessed it would be straightforward to use. Is there a ChucK object browser, or any way to print all the properties of an object? Ollie > Hey there, > Sorry for the late reply. There isnt any documentation for it, but > its pretty simple. In case youre still wondering, heres an example > that just sends a noteOn and noteOff. > > // data structures > MidiOut mout; > MidiMsg msg; > > // connect > if( !mout.open( 0 ) ) me.exit(); > <<< "connected to MIDI port 0", "" >>>; > > // noteOn > 0x90 => msg.data1; > 60 => msg.data2; > 127 => msg.data3; > > // send > mout.send( msg ); > > // wait > 1::second => now; > > > 0x80 => msg.data1; > 60 => msg.data2; > > mout.send( msg ); > > > > hope this helps, > spencer > > On Jun 5, 2006, at 8:07 AM, Ollie Glass wrote: > > > Is there any documentation available for the MidiOut object? > > > > Thanks, > > > > Ollie > > _______________________________________________ > > chuck-users mailing list > > chuck-users(a)lists.cs.princeton.edu > > https://lists.cs.princeton.edu/mailman/listinfo/chuck-users > > > > > _______________________________________________ > chuck-users mailing list > chuck-users(a)lists.cs.princeton.edu > https://lists.cs.princeton.edu/mailman/listinfo/chuck-users > > >

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