midichn — Returns the MIDI channel number from which the note was activated.
midichn returns the MIDI channel number (1 - 16) from which the note was activated. In the case of score notes, it returns 0.
ichn -- channel number. If the current note was activated from score, it is set to zero.
Here is a simple example of the midichn opcode. It uses the file midichn.csd.
Example 593. Example of the midichn opcode.
See the sections Real-time Audio and Command Line Flags for more information on using command line flags.
<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”.
Example 594. An advanced example of the midichn opcode.
<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