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xtratim

Extend the duration of real-time generated events and handle their extra life (Usually for usage along with release instead of linenr, linsegr, etc).

Syntax

xtratim iextradur

Initialization

iextradur -- additional duration of current instrument instance

Performance

xtratim extends current MIDI-activated note duration by iextradur seconds after the corresponding noteoff message has deactivated the current note itself. It is usually used in conjunction with release. This opcode has no output arguments.

This opcode is useful for implementing complex release-oriented envelopes, whose duration is not known when the envelope starts (e.g. for real-time MIDI generated events).

Examples

Here is a simple example of the xtratim opcode. It uses the file xtratim.csd.

Example of the xtratim opcode.
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<CsoundSynthesizer>

<CsOptions>
; Select audio/midi flags here according to platform
; Audio out   Audio in    Silent  MIDI in
-odac           -iadc     -d       -M0  ;;;realtime I/O
</CsOptions>

<CsInstruments>
;Simple usage of the xtratim opcode
sr = 44100
ksmps = 10
nchnls = 2

; sine wave for oscillators
gisin       ftgen     1, 0, 4096, 10, 1

instr 1

  inum notnum
  icps cpsmidi
  iamp ampmidi 4000
 ;
 ;------- complex envelope block ------
  xtratim 1 ;extra-time, i.e. release dur
  krel init 0
  krel release ;outputs release-stage flag (0 or 1 values)
  if (krel == 1) kgoto rel ;if in release-stage goto release section
 ;
 ;************ attack and sustain section ***********
  kmp1 linseg 0, .03, 1, .05, 1, .07, 0, .08, .5, 4, 1, 50, 1
  kmp = kmp1*iamp
   kgoto done
 ;
 ;--------- release section --------
   rel:
  kmp2 linseg 1, .3, .2, .7, 0
  kmp = kmp1*kmp2*iamp
  done:
 ;------
  a1 oscili kmp, icps, gisin
  outs a1, a1
 endin

</CsInstruments>

<CsScore>
f 0 3600 ;dummy table to wait for realtime MIDI events
e
</CsScore>

</CsoundSynthesizer>

Here is a more elaborate example of the xtratim opcode. It uses the file xtratim-2.csd.

This example shows how to generate a release segment for an ADSR envelope after a MIDI noteoff is received, extending the duration with xtratim and using release to check whether the note is on the release phase. Two envelopes are generated simultaneously for the left and right channels.

More complex example of the xtratim opcode.
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<CsoundSynthesizer>

<CsOptions>
; Select audio/midi flags here according to platform
; Audio out   Audio in    Silent  MIDI in
-odac           -iadc     -d       -M0  ;;;realtime I/O
</CsOptions>

<CsInstruments>
;xtratim example by Jonathan Murphy Dec. 2006
sr = 44100
ksmps = 10
nchnls = 2

            ; sine wave for oscillators
gisin       ftgen     1, 0, 4096, 10, 1
            ; set volume initially to midpoint
            ctrlinit  1, 7,64

;;; simple two oscil, two envelope synth
    instr 1

            ; frequency
  kcps      cpsmidib
            ; initial velocity (noteon)
  ivel      veloc

            ; master volume
  kamp      ctrl7     1, 7, 0, 127
  kamp      =  kamp * ivel

            ; parameters for aenv1
  iatt1     =  0.03     
  idec1     =  1
  isus1     =  0.25     
  irel1     =  1
            ; parameters for aenv2
  iatt2     =  0.06     
  idec2     =  2        
  isus2     =  0.5
  irel2     =  2

            ; extra (release) time allocated
            xtratim   (irel1>irel2 ? irel1 : irel2)
            ; krel is used to trigger envelope release
  krel      init      0
  krel      release
            ; if noteoff received, krel == 1, otherwise krel == 0
if (krel == 1) kgoto rel

            ; attack, decay, sustain segments
  atmp1     linseg    0, iatt1, 1, idec1, isus1 , 1, isus1
  atmp2     linseg    0, iatt2, 1, idec2, isus2 , 1, isus2
  aenv1     =  atmp1
  aenv2     =  atmp2
            kgoto     done

            ; release segment
rel:
  atmp3     linseg    1, irel1, 0, 1, 0
  atmp4     linseg    1, irel2, 0, 1, 0
  aenv1     =  atmp1 * atmp3  ;to go from the current value (in case
  aenv2     =  atmp2 * atmp4  ;the attack hasn't finished) to the release.

            ; control oscillator amplitude using envelopes
done:
  aosc1     oscil     aenv1, kcps, gisin
  aosc2     oscil     aenv2, kcps * 1.5, gisin
  aosc1     =  aosc1 * kamp
  aosc2     =  aosc2 * kamp

            ; send aosc1 to left channel, aosc2 to right,
            ; release times are noticably different

            outs      aosc1, aosc2

    endin

</CsInstruments>

<CsScore>

f 0 3600 ;dummy table to wait for realtime MIDI events

</CsScore>

</CsoundSynthesizer>

See also

Event Extenders

Credits

Author: Gabriel Maldonado

Italy

Examples by Gabriel Maldonado and Jonathan Murphy

New in Csound version 3.47