May 2009 - chuck-users - lists.cs.princeton.edu

other ways to live-code with time
by Tom Lieber 08 May '09

08 May '09

impromptu is a live-coding environment for OS X that looks very interesting, definitely something I need to try out once I've escaped the clutches of my end-of-year work. http://impromptu.moso.com.au/ I thought I'd bring it up not only because it's interesting, but because its tutorial on "time" contrasts impromptu's asynchronous model with ChucK's synchronous one: in impromptu, time passes while your code is running. You can read the tutorial here: http://impromptu.moso.com.au/tutorials/time.html Just think... you could load a WAV file without hanging the VM! It's interesting to see what you get when you trade one complication (waiting on slow shreds) for another (having "now" change beneath your feet). Here are some, from the tutorial: "There are a couple of gotcha's to keep in mind when doing schedule and forget programming. The first thing to keep in mind is that (now) is an airy fairy thing. In the example below the two notes may be scheduled to play on the same sample - but then again, they may not - (now) may have moved forward in time between the two calls (even if evaluated at the same time). (play-note (now) piano 60 80 *second*) (play-note (now) piano 72 80 *second*) "Often this lack of precision is fine (i.e. too small a change to be noticeable) but where absolute accuracy is required a time variable should be used. (let ((time (now))) (play-note time piano 60 80 *second*) (play-note time piano 72 80 *second*)) "This inaccuracy becomes more of an issue when amplified over time such as using (now) inside a recursive callback loop. We can avoid the problem by precisely incrementing a time value between each recursive callback (note that any arguments required by the function being called back must also be passed to callback). ;This is bad (define loop (lambda () (play-note (now) piano 60 80 *second*) (callback (+ (now) *second*) 'loop))) (loop) ;This is good (precise time arg is now incremented each recursion) (define loop (lambda (time) (play-note time piano 60 80 *second* ) (callback (+ time *second*) 'loop (+ time *second*)))) (loop (now)) "The second major gotcha in recursive callback loops is that (now) is now. Code requires some time to execute. If you are executing a call to evaluate a note (now) by the time the code is evaluated it will already be late. You should always try to schedule your code execution ahead of the scheduled time of your tasks. ;This is best (callback happens 4100 samples earlier than new time) (define loop (lambda (time) (play-note time piano 60 80 1.0) (callback (+ time 40000) 'loop (+ time 44100)))) (loop (now)) "In the this-is-good version of loop the time sent as an argument to loop is exactly the same time as the scheduled callback time. The problem with this is that the next note needs to be scheduled at exactly the same time that the function is called. The note will always be late. The this-is-best version schedules the callback just ahead of the time that we want to schedule the note. This gives us 4100 samples to execute the code to schedule the note before the note is required to sound." The last sentence reminds me of the thread a while back about benchmarking UGens. :) -- Tom Lieber http://AllTom.com/

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Re: [chuck-users] The ChucK Show
by Les Hall 06 May '09

06 May '09

When do you need it by, Les? I have to put together something for my thesis presentation on Friday. The project involves data-sonification and ChucK is my weapon of choice. _mike mike, Anytime is fine, i'll just include it in the next show whenever I get it. Cheers, Les (Inventor)

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WvIn on osx and linux
by jo 06 May '09

06 May '09

Hi, have been using WvIn for some while as a workaround to read a data file into chuck (this was suggested by someone in an earlier post), e.g. WvIn w => blackhole; "data.wav" => w.path; float n; repeat(20) { 1::samp => now; w.last() => n; <<< n >>>; } This works fine on my mac. However, when I try to do this in linux, it fails, sort of. The first value is the same as on os x, but then they deviate, not completely, but significantly (more than 10%), so it can't be a simple rounding error. I'm relatively sure that the values on the mac are correct because I write the data to the wav file myself. It's not obvious to me why the reading of any .wav file (using last()) should produce different values on different operating systems, but they do on my computers! Does anyone know what could be going on here? thanks, jo

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Re: [chuck-users] The ChucK Show
by Les Hall 05 May '09

05 May '09

Kas, moved Antimon to the intermediates section. Sure, I'll post the code to the forum. Rob, Source code would definitely be appreciated, that way folks can learn from your code and rip it up if they want to, lol! Just post it to the forum or the list or email it to me, any way will do fine. Oh, yes, go to the ChucK site and click on wiki to get to the wiki. Yeah! Les (Inventor)

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The ChucK Show
by Les Hall 05 May '09

05 May '09

Hi folks, The theme for the seventh ChucK show is "from newbie to expert". We will feature ChucK code written by newbies, intermediates, and experts. The newbies have been sending me some really awesome code, and there is some intermediate code plus lots of expert mp3's from the wiki. Here is the outline of next week's show, so far: Beginners remder-3c: kijjaz's friend in Thailand, 3rd ChucK program ever! RitualMusicfromBetelgeuse: Slinky's second ChucK program! telstar3: telstarmagickistferarri, a member of our community WindAntimon: intended for the "winds of change show" wmonk: ChucKist of the week: 20 year old college student programming since 10 years old, so 10 years of experience inspired by the show, Linux user, set up ChucK in the chatroom within 15 minutes had a program: wmonk.mp3 Then shortly after that wmonk2.mp3 Fast Learner!!! Intermediates Guitar Lab Rock3: me on ChucK Guitar Lab stooges: by Rob, 3 stooges do Zappa, lol Experts Electrindian: Michael Hammond from 2005 for assignment 2 of PLOrk HackChuck: by Perry Cook for Ge Wang's PhD graduation marco polo: R. W. Enoch from 2005 for assignment 2 of PLOrk otfc2005x: Peerry Cook and Ge Wang, Performed on the fly to an audience sounds like a robot being born and then youth and then adulthood Smooth Criminal: Tribute to Michael Jackson by Perry Cook WindChimes: by kijjaz, mistakenly not played on winds of change show This is fine, and will fill up the hour, but after this the outlook appears kind of light for material. I'd like to know what the links are for PLOrk, SLOrk, and other ChucKian organizations where I can shamelessly rip code or mp3's from to keep the show interesting and novel. There's a lot of ChucK activity out there and I want to tap into it, so could someone please link me up? Thanks, Les (Inventor)

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OSC on iPhone/iPod touch
by Mark Cerqueira 04 May '09

04 May '09

I was perusing the App Store and found this app under "Staff Favorites" TouchOSC is an iPhone / iPod Touch application that lets you send and receive Open Sound Control messages over a Wi-Fi network using the UDP protocol. http://hexler.net/software/touchosc Has anyone tried this app with OSC ChucK? Perhaps if this app proves to be useful, we can convince Dan to get us all iPods for PLOrk- related-business.... iPLOrk? Best, Mark

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Amusing ditty for the day
by Robert Poor 04 May '09

04 May '09

I was experimenting with some ChucK-ian control structures, and, well, er, um, heh. Ahem. Think of it as "The Three Stooges play Zappa's interpretation of Edgard Varese". For two minutes of amusement only: http://homepage.mac.com/rpoor/Music/stooges.mp3 ...now they'll *never* let me into La Sorbonne... - Rob

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To cheer us up on a rainy day, a Michael Jackson Tribute Hack!
by Perry R Cook 03 May '09

03 May '09

http://www.cs.princeton.edu/~prc/SmoothCriminal.ck

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Re: [chuck-users] The ChucK Show
by Les Hall 03 May '09

03 May '09

Hey folks, The last two weeks of The ChucK Show went well. The whole Paranoid Schizophrenia album went over just fine and yesterday we did a two hour show to cover for Shane who's power went out. Kassen showed up and had fun in the chatroom and dtoliaferro was there too. kewl. The link for recordings has changed, here is the new semi-permanent link: http://electro-music.com/radio/archives/ Hope you can give a listen to Sunshine and myself.... Les (Inventor)

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Re: [chuck-users] dbtopow(), dbtorms(), powtodb(), powtorms() off by 100 db (Robert Poor)
by Perry R Cook 03 May '09

03 May '09

Oh yea, that too :-) Thanx Adam. PRC ----- "Perry R Cook" <prc(a)cs.princeton.edu> wrote: > dB just implies 20log_10. A reference must be selected. > > The most common are dBV (1 volt = 0dB), dBm (0dB = 1 milliwatt into > 600 ohms), and dBSPL (watts relative to threshold of hearing at 0dB). > > I suspect that the implementers of this were thinking about > the approximate 96dB of 16 bit audio, and the +/-1.0 float > recommended max range of STK. Thus a range of 0.00001=0dB > to 1.0=100dB resulted. Easy to change to any reference by > just subtracting/adding/multiplying/dividing by a constant. > > PRC

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