[chuck] recording your session to file

Ge Wang gewang at CS.Princeton.EDU
Sat Oct 2 04:31:42 EDT 2004

It's me again (sorry).

Here is a brief tutorial on writing to disk...

1. recording your ChucK session to file is easy!

example:  you want to record the following:

     > chuck foo.ck bar.ck

all you's got to do is ChucK a shred that writes to file:

     > chuck foo.ck bar.ck rec.ck

no changes to existing files are necessary.
an example rec.ck can be found in examples/, this
guy/gal writes to "foo.wav".  edit the file to change.
if you don't want to worry about overwriting the same
file everytime, you can:

     > chuck foo.ck bar.ck rec2.ck

rec2.ck will generate a file name using the current
time.  You can change the prefix of the filename by

     "data/session" => w.autoPrefix;

w is the WvOut in the patch.

Oh yeah, you can of course chuck the rec.ck on-the-fly...

from terminal 1
     > chuck --loop

from terminal 2
     > chuck + rec.ck

2. silent mode

you can write directly to disk without having real-time audio
by using --silent or -s

     > chuck foo.ck bar.ck rec2.ck -s

this will not synchronize to the audio card, and will generate
samples as fast as it can.

3. start and stop

you can start and stop the writing to file by:

     1 => w.record;  // start
     0 => w.record;  // stop

as with all thing ChucKian, this can be done

4. another halting problem

what if I have infinite time loop, and want to terminate
the VM, will my file be written out correctly?  the answer:

Ctrl-C works just fine.

ChucK STK module keeps track of open file handles and
closes them even upon abnormal termination, like Ctrl-C.
Actually for many, Ctrl-C is the natural way to end your
ChucK session.  At any rate, this is quite ghetto, but it works.
As for seg-faults and other catastrophic events, like computer
catching on fire from ChucK exploding, the file probably is

hmmmm, toast...

5. the silent sample sucker strikes again

as in rec.ck, one patch to write to file is:

dac => gain g => WvOut w => blackhole;

the blackhole drives the WvOut, which in turns sucks
samples from gain and then the dac.  The WvOut
can also be placed before the dac:

noise n => WvOut w => dac;

The WvOut writes to file, and also pass through the incoming samples.

6. post your files online


7. I need to go to sleep.

this concludes the brief tutorial.


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