xtratim
Prev | Orchestra Opcodes and Operators | Next

## 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 1152. 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 1153. 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

Prev | Up | Next
xscanu | Home | xyin