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midichn

Returns the MIDI channel number (1 - 16) from which the note was activated.

In the case of score notes, it returns 0.

Syntax

ichn midichn

Initialization

ichn -- channel number. If the current note was activated from score, it is set to zero.

Examples

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

Example of the midichn opcode.
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<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac -M0 -+rtmidi=virtual ;;; midi file input
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
0dbfs  = 1

instr 1  
;change channel on virtual midi keyboard
i1 midichn
   print i1

endin
</CsInstruments>
<CsScore>
f 0 20  ;runs for 20 seconds

e
</CsScore>
</CsoundSynthesizer>

Here is an advanced example of the midichn opcode. It uses the file midichn_advanced.csd.

Do not forget that you must include the -F flag when using an external MIDI file like “midichn_advanced.mid”.

An advanced example of the midichn opcode.
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<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac -F midichn_advanced.mid ;;;realtime audio out with MIDI file input
; For Non-realtime ouput leave only the line below:
; -o midichn_advanced.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
0dbfs  = 1

        massign  1, 1           ; all channels use instr 1
        massign  2, 1
        massign  3, 1
        massign  4, 1
        massign  5, 1
        massign  6, 1
        massign  7, 1
        massign  8, 1
        massign  9, 1
        massign 10, 1
        massign 11, 1
        massign 12, 1
        massign 13, 1
        massign 14, 1
        massign 15, 1
        massign 16, 1

gicnt   =  0            ; note counter

        instr 1

gicnt   =  gicnt + 1    ; update note counter
kcnt    init gicnt      ; copy to local variable
ichn    midichn         ; get channel number
istime  times           ; note-on time

        if (ichn > 0.5) goto l2         ; MIDI note
        printks "note %.0f (time = %.2f) was activated from the score\\n", \
                3600, kcnt, istime
        goto l1
l2:
        printks "note %.0f (time = %.2f) was activated from channel %.0f\\n", \
                3600, kcnt, istime, ichn
l1:

icps    cpsmidi         ; convert midi note to pitch
kenv    madsr   0.1, 0, 0.8, 0.9
asig    pluck   kenv, icps, icps, 1, 1   
        outs    asig, asig

endin
</CsInstruments>
<CsScore>
t 0 60          ;beats per minute

f 0 8           ;stay active for 8 seconds
f 1 0 4096 10 1 ;sine

e
</CsScore>
</CsoundSynthesizer>

Its output should include lines like:

note 1 (time = 0.00) was activated from channel 1
note 2 (time = 2.00) was activated from channel 4
note 3 (time = 3.00) was activated from channel 2
note 4 (time = 5.00) was activated from channel 3

See also

MIDI input and Initialization

MIDI/Score Interoperability

Credits

Author: Istvan Varga
May 2002

New in version 4.20