PlayBuf sample playback oscillator



Plays back a sample resident in memory.



PlayBuf.ar(numChannels,bufnum,rate,trigger,startPos,loop)


numChannels - number of channels that the buffer will be.

this must be a fixed integer. The architechture of the SynthDef

cannot change after it is compiled.

warning: if you supply a bufnum of a buffer that has a different

numChannels then you have specified to the PlayBuf, it will

fail silently.

bufnum - the index of the buffer to use

rate   - 1.0 is the server's sample rate, 2.0 is one octave up, 0.5 is one octave down

-1.0 is backwards normal rate ... etc. Interpolation is cubic.

Note: If the buffer's sample rate is different from the server's, you will need to

multiply the desired playback rate by (file's rate / server's rate). The UGen

BufRateScale.kr(bufnum) returns this factor. See examples below.

BufRateScale should be used in virtually every case.

trigger - a trigger causes a jump to the startPos. 

A trigger occurs when a signal changes from <= 0 to > 0.

startPos - sample frame to start playback.

loop       - 1 means true, 0 means false.  this is modulate-able.




(

// read a whole sound into memory

s = Server.local;

// note: not *that* columbia, the first one

b = Buffer.read(s,"sounds/a11wlk01.wav"); // remember to free the buffer later.

)


SynthDef("help_PlayBuf", { arg out=0,bufnum=0;

Out.ar(out,

PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum))

)

}).play(s,[\out, 0, \bufnum, b.bufnum]);


Note again that the number of channels must be fixed for the SynthDef. It cannot vary depending on which buffer you use.



// loop is true

SynthDef("help_PlayBuf", { arg out=0,bufnum=0;

Out.ar(out,

PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum), loop: 1.0)

)

}).play(s,[\out, 0, \bufnum, b.bufnum]);




// trigger one shot on each pulse

SynthDef("help_PlayBuf", { arg out=0,bufnum=0;

var trig;

trig = Impulse.kr(2.0);

Out.ar(out,

PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum), trig, 0, 0)

)

}).play(s,[\out, 0, \bufnum, b.bufnum]);



// trigger one shot on each pulse

SynthDef("help_PlayBuf", { arg out=0,bufnum=0;

var trig;

trig = Impulse.kr(XLine.kr(0.1, 100, 30));

Out.ar(out,

PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum), trig, 5000, 0)

)

}).play(s,[\out, 0, \bufnum, b.bufnum]);





// mouse control of trigger rate and startpos

SynthDef("help_PlayBuf", { arg out=0, bufnum=0;

var trig;

trig = Impulse.kr(MouseY.kr(0.5,200,1));

Out.ar(out,

PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum), trig, MouseX.kr(0, BufFrames.kr(bufnum)), 1)

)

}).play(s,[\out, 0, \bufnum, b.bufnum]);




// accelerating pitch

SynthDef("help_PlayBuf", { arg out=0,bufnum=0;

var rate;

rate = XLine.kr(0.1, 100, 60);

Out.ar(out, 

PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum)*rate, 1.0, 0.0, 1.0)

)

}).play(s,[\out, 0, \bufnum, b.bufnum]);




// sine wave control of playback rate. negative rate plays backwards

SynthDef("help_PlayBuf", { arg out=0,bufnum=0;

var rate;

rate = FSinOsc.kr(XLine.kr(0.2, 8, 30), 0, 3, 0.6);

Out.ar(out,

PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum) * rate, 1, 0, 1)

)

}).play(s,[\out, 0, \bufnum, b.bufnum]);



// zig zag around sound 

SynthDef("help_PlayBuf", { arg out=0,bufnum=0;

var rate;

rate = LFNoise2.kr(XLine.kr(1, 20, 60), 2);

Out.ar(out,

PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum) * rate, 1, 0, 1)

)

}).play(s,[\out, 0, \bufnum, b.bufnum]);



b.free;

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