midinoteoncps
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## midinoteoncps

midinoteoncps — Gets a MIDI note number as a cycles-per-second frequency.

## Description

midinoteoncps is designed to simplify writing instruments that can be used interchangeably for either score or MIDI input, and to make it easier to adapt instruments originally written for score input to work with MIDI input.

In general, it should be possible to write instrument definitions that work identically with both scores and MIDI, including both MIDI files and real-time MIDI input, without using any conditional statements, and that take full advantage of MIDI voice messages.

Note that correlating Csound instruments with MIDI channel numbers is done using the massign opcode for real-time performance,. For file-driven performance, instrument numbers default to MIDI channel number + 1, but the defaults are overridden by any MIDI program change messages in the file.

## Syntax

    midinoteoncps xcps, xvelocity

## Performance

xcps -- returns MIDI key translated to cycles per second during MIDI activation, remains unchanged otherwise.

xvelocity -- returns MIDI velocity during MIDI activation, remains unchanged otherwise.

If the instrument was activated by MIDI input, the opcode overwrites the values of xcps and xvelocity with the corresponding values from MIDI input. If the instrument was NOT activated by MIDI input, the values of xcps and xvelocity remain unchanged.

This enables score p-fields to receive MIDI input data during MIDI activation, and score values otherwise.

| Adapting a score-activated Csound instrument.
See the MIDI interop opcodes section for details on adapting score driven instruments for MIDI or vice-versa.

## Examples

Here is an example of the midinoteoncps opcode. It uses the file midinoteoncps.csd.

Example 450. Example of the midinoteoncps 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
    ; Audio out   Audio in   No messages  MIDI in
    -odac           -iadc     -d         -M0  ;;;RT audio I/O with MIDI in
    ; For Non-realtime ouput leave only the line below:
    ; -o midinoteoncps.wav -W ;;; for file output any platform
    </CsOptions>
    <CsInstruments>

    ; Initialize the global variables.
    sr = 44100
    kr = 4410
    ksmps = 10
    nchnls = 1

    ; Instrument #1.
    instr 1
      kcps init 0
      kvelocity init 0

      midinoteoncps kcps, kvelocity

      ; Display the cycles-per-second value when it changes.
      printk2 kcps
    endin

    </CsInstruments>
    <CsScore>

    ; Play Instrument #1 for ten seconds.
    i 1 0 10
    e

    </CsScore>
    </CsoundSynthesizer>

Its output should include lines like:

     i1   261.62561
     i1   440.00006

## See Also

midichannelaftertouch, midicontrolchange, mididefault, midinoteoff, midinoteonkey, midinoteonoct, midinoteonpch, midipitchbend, midipolyaftertouch, midiprogramchange

## Credits

Author: Michael Gogins

Example written by Kevin Conder.

New in version 4.20

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