Hi, new “Norns” user here.
enjoying it very much so far … except, I’m trying, but failing to get the “BeatTrack” (or “AutoTrack”) ugen working: https://doc.sccode.org/Classes/AutoTrack.html
I was adapting the PlayThrough template and have it/something somewhat, but the tracking (via audio out) is fairly wonky, it seems (I’m trying with some vanilla 4/4 techno); and I can’t seem to poll the tempo value, it’s always stuck at 128 (see the bpm.callback below).
below is my Engine + Lua test file. Any pointers welcome (or hints re alternatives, the output I’m seeing isn’t particularly promising, but chances are I’m doing something wrong. (Fwiw: trying to get this working to extract the BPM of the incoming audio for looping/sync purposes)
engine:
Engine_BeatTrack : CroneEngine {
var bpm_=128;
var <synth;
// this is your constructor. the ‘context’ arg is a CroneAudioContext.
// it provides input and output busses and groups.
// see its implementation for details.
*new { arg context, doneCallback;
^super.new(context, doneCallback);
}
// this is called when the engine is actually loaded by a script.
// you can assume it will be called in a Routine,
// and you can use .sync and .wait methods.
alloc {
//Add SynthDefs
SynthDef(\track_BPM, { | inL, inR, out, bpm_=128 |
var trackb, trackh, trackq, tempo;
var bsound, hsound, qsound;
var source;
// read mono
source = In.ar(inL);
#trackb, trackh, trackq, tempo = AutoTrack.kr(source);
bpm_ = tempo;
bsound = Pan2.ar(LPF.ar(WhiteNoise.ar * Decay.kr(trackb, 0.05), 1000), 0.0);
Out.ar(out, bsound);
}).add;
context.server.sync;
synth = Synth.new(\track_BPM, [
\inL, context.in_b[0].index,
\inR, context.in_b[1].index,
\out, context.out_b.index,
\bpm_, 128],
context.xg);
// this is how you add “commands”,
// which is how the lua interpreter controls the engine.
// the format string is analogous to an OSC message format string,
// and the ‘msg’ argument contains data.
this.addPoll("bpm", { bpm_ });
}
free {
// here you should free resources (e.g. Synths, Buffers &c)
// and stop processes (e.g. Routines, Tasks &c)
synth.free;
}
}
lua:
– bpm test
engine.name = ‘BeatTrack’
local audio = require ‘audio’
function init()
print("bpm … ? ")
audio.level_monitor(0)
bpm = poll.set(“bpm”)
bpm.time = 0.5
bpm.callback = function(val)
print(val)
end
bpm:start()
end
Thanks!
