xtratim

xtratim — Extend the duration of real-time generated events.

Description

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 1028. Example of the xtratim opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

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.

<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.

Example 1029. More complex example of the xtratim opcode.

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.

<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

linenr, release

Credits

Author: Gabriel Maldonado

Italy

Examples by Gabriel Maldonado and Jonathan Murphy

New in Csound version 3.47