[chuck-users] WvOut sample size (????????? ????????)

Perry Cook prc at CS.Princeton.EDU
Sat Jan 24 14:54:13 EST 2015

It's likely just overloading and clipping on the output file.  WvOut
and WvOut2 must quantize to 16 bits to write out the file.  So 
numbers that are greater than +/- 1.0 will overload.  If this is
really the problem (likely), then there's an easy fix.  There's a
method called fileGain() that sets an extra gain before the file
is written out.  The default is of course 1.0, but you can change
it to anything.  Example useage:

MyPatch => WvOut bob => blackhole;
"mywavfile.wav" => bob.wavFilename;

0.5 => bob.fileGain;       // This is your friend for writing non-clipped files

while (now < then)  {
    // do whatever;


Hope this helps.  If not let us know and we'll dig deeper.


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>   1. WvOut  sample size (????????? ????????)
> ----------------------------------------------------------------------
> Message: 1
> Date: Fri, 23 Jan 2015 20:22:21 +0100
> From: ????????? ???????? 	<vitalije at kviziracija.net>
> To: chuck-users at lists.cs.princeton.edu
> Subject: [chuck-users] WvOut  sample size
> Message-ID: <54C29F6D.8070701 at kviziracija.net>
> Content-Type: text/plain; charset=utf-8; format=flowed
> Hello,
> I am a new member of this list.
> I have made some ChucK program that sounds good when performed by ChucK 
> VM. However, when I record this music through WvOut in to file and later 
> play recorded file using system player, I hear some cracks (distortions, 
> noise).
> It seems to me that it is some conversion taking place during recording. 
> In  the documentation of WvOut class it is suggested that MATLAB file 
> format will write 64-bit floats. But even with that precision I get the 
> same sound in file. I have looked in to the source code and found that 
> every method of WvOut class (WvOut_ctrl_<filetype>Filename) opens file 
> with the same 16-bit sample-size (Stk::STK_SINT16).
> I have tried naively to change that parameter into Stk::STK_SINT32, and 
> recompiled successfully ChucK, but the quality of recorded sound was not 
> improved. Actually, file was again 16-bit signed encoded.
> What can I do to improve quality of recording.
> My computer is amd-64 Ubuntu 14.04. I have compiled ChucK with 'make 
> linux-alsa' command.
> PS: I tried to record sound from system sound-card by using some other 
> programs for recording, but with no success. Either ChucK could not 
> access sound-card or a recording program could not access sound-card. It 
> seems that ChucK insists on having exclusive rights over sound-card and 
> doesn't want to share it with other programs. Even if in my browser is 
> opened some site that uses sound, ChucK refuses to start.
> Vitalije
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