Record into Buffers

Today, we had another TAI SIG lecture, this time on creating loops from sounds based on thresholding. Here’s the code we came up with during the course:

s.boot;

// use the GUI to start/stop Ndefs and set additional parameters
NdefMixer(s);

// create an event to put things
q = ();

/* example for event usage
q.class; // event
q.roberto = "sunny"; // add something
q.roberto; // recall value
*/

// create a buffer to record sounds
q.sampleBuffer = Buffer.alloc(s, s.sampleRate * 2.0, 1);

/*
q.sampleBuffer.play; // play Buffer
q.sampleBuffer.plot; // plot Buffer
q.sampleBuffer.zero; // empty Buffer
*/

(
// record sound into buffer as soon as amplitude of signal > threshold
Ndef(record, {|threshold = 0.4, bufnum = 0, recRate = 1|
  var in, amp, trig;

  in = SoundIn.ar(0); // the input signal
  // calculate amplitude of signal with attack-time 0:
  amp = Amplitude.kr(in, 0);
  trig = amp > threshold; // 1 if amp > threshold, 0 else
  trig = Trig.kr(trig, 0.1); // 1 for 0.1 secs

  RecordBuf.ar(
    in, bufnum,
    0, 1, 0, 1, 0,
    trig
  );
});

// set the correct bufnum
Ndef(record).set(bufnum, q.sampleBuffer.bufnum);
)

(
// playback recording every dt seconds with a modulable rate
Ndef(playback, {|bufnum = 0, rate = 1, dt = 4|
  var trig;

  trig = Impulse.kr(1/dt);
  BufRd.ar(
    1,  bufnum,
    EnvGen.ar(
      Env(
        [0, BufFrames.kr(bufnum), 0], // values
        [BufDur.kr(bufnum) * rate.reciprocal, 0], // times
        'linear' // interpolation type
      ),
      gate: trig
    ),
    0, 2
  );
});

Ndef(playback).set(bufnum, q.sampleBuffer.bufnum);
)

/*
// a testbuffer to see if playback does the right thing
q.testBuffer = Buffer.readChannel(
  s, "sounds/SinedPink.aiff", channels: [0]
);
q.testBuffer.plot
Ndef(playback).set(bufnum, q.testBuffer.bufnum);
*/

// cleaning up / destroy the world we created
q.sampleBuffer.free;