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MIDI Input Element

MIDI Input Element allows read and log an input coming from MIDI devices connected to a computer. MIDI is a commonly-accepted protocol for communication with digital musical instruments, like MIDI piano keyboards. The MIDI Input element can record a instrumental music played in real-time as a sequence of notes.
The element is proposed for experiments, where participant's input is produced by playing a music on MIDI compatible instruments.

Table of Contents [Hide/Show] Summary Properties Description Demo video Examples Practical Use     Technique 1: Logging all MIDI input over a period of time     Technique 2: Detecting a time of the first played note or pressed piano button

Description ¶

On onset of the parent event the MIDI input element starts to read a real-time input of the selected MIDI Device and record all played notes and other events. Recorded information about a single note includes the MIDI channel number, note name, playback start time, duration, octave number, note's sound frequency and button press velocity (or volume). The element can also detect presses of the control buttons, e.g. program change by reading the low-level MIDI events. The recorded notes and events can be easily accessed in code snippets, used for a flow control in experiment or be just logged.

Demo video ¶

Examples ¶

Traditional note signs and corresponding element's note names and sound frequencies

Example of single note info, recorded by the element:

MIDI Channel: 0
Note: C
Octave: -5
Time: 307 ms
Duration: 562 ms
Frequency: 8.18 Hz
Press Velocity: 45

Practical Use ¶

Technique 1: Logging all MIDI input over a period of time ¶

1. Add new MIDI input element into the event where you plan to record notes played by a participant
2. Select the input MIDI device via MIDI Device property. The device has to be connected to PC and turn on
3. Choose whether you want to record all low-level MIDI events or just MIDI notes
4. Add a proxy variable on the MIDI Notes property. After the parent event ends, the proxy variable will returns all played notes as an array of clMIDINote structs
5. Read the MIDI notes array and record it into Report or into a custom file, like in the following snippet:
   

    //
   
   for (int i=0;i<MIDINotes.Length;i++)
   
   {
   
   Report=Report+MIDINotes[i].Note+";"+MIDINotes[i].Octave+";"+MIDINotes[i].StartTime+";"+MIDINotes[i].Duration+"\n\r"; /// record the note info into Report
   
   }
   
   

   
   There is no need to clean up the array because the MIDI Notes property is automatically reset on the next onset on the parent event
   

Technique 2: Detecting a time of the first played note or pressed piano button ¶

1. Add new MIDI input element into the event where you plan to record a note played by a participant
2. Select the input MIDI device via MIDI Device property. The device has to be connected to PC and turn on
3. Choose whether you want to detect a note (after button release) or button press. In the latter case, change the Triggering Mode to "On MIDI event"
4. Add proxy variables on the Last Note or Last Event property Is Triggered property. You can use Is Triggered as the event end condition via conditional flow route.
5. Write a recording code to the Triggered snippet of the MIDI Input element. The code may look like this:
   

    // if you want to detect a note
   
   Report=Report+LastNote.Name+";"+LastNote.Octave+";"+LastNote.StartTime+";"+LastNote.Duration+"\n\r";
   
   

   
   or
   

    // if you want to detect an initial press of piano button
   
   if ((LastEvent.Name=="NoteOn")&&(LastEvent.Data2>0)) /// select only the 'button-down' events
   
   Report=Report+LastEvent.Name+";"+LastEvent.MIDIChannel+";"+LastEvent.Time+";"+LastNote.Data1+";"+LastNote.Data2+"\n\r";
   
   

   
   The code will be executed when an incoming note or piano button press is detected. Instruct participants to do not press several buttons simultaneously because, only the last one will be detected by the given technique.
   
   

	Name	Size
	MIDI-Input-Element-Icon.png	3.16 KB