[chuck-users] WvOut: writes soundfile, but always silent

Click Nilson clicksonnil at gmail.com
Sun Aug 26 10:51:13 EDT 2012

Hi all, 

Just trying chimera to see what is up in ChucK world. 

I've found that I can't get WvOut to work; I've tried innumerable permutations, from:
chuck curly.ck rec.ck 
to the code examples below. I can get an output sound file, but it's always silent (though the right length). I've tried different orders of WvOut and dac, and many variations (including wav and aif output). Is this a known problem, or is there some other official way to do this that supersedes the manual included with the distribution? I couldn't find any resolution hunting on old posts from this mailing list. 

(my system: 10.6.8 OS X)

I also find attempting --silent or -s that I just get the system locking up, and a crash on ctrl+c: 

chuck_oo.cpp:125: failed assertion `m_ref_count > 0'
Assertion failed: (libcompiler_rt abort), function __eprintf, file /SourceCache/clang/clang-421.0.60/src/projects/compiler-rt/lib/eprintf.c, line 31.
Abort trap


simple test, from an old chuck-users posting: 

Noise whitenoise => dac;
whitenoise => WvOut waveOut => blackhole;  
0.5 => whitenoise.gain;
2::second => now;

more complicated (I want to do sample by sample synthesis and write out a sound file):  

//sample by sample writing of audio in ChucK
//for maximal speed in NRT mode, run chuck with -s flag or --silent
//e.g. ./chuck /data/sussex/courses/advancedCM/lectures/samplelevel/writesoundfile.ck --silent

Impulse i => dac; 

//=> Gain g 
dac => WvOut w => blackhole;

"chuckoutput.wav" => w.wavFilename;

1 => w.record;

//.9 => g.gain;

now + 2::second => time later;

//workaround to save file on end of synthesis: see examples/basic/rec.ck
//null @=> w;

while( now < later ) {	
//set current value of Impulse UGen
Std.randf() => i.next; 

1::samp => now; 

0 => w.record;


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