midireceive

Receive MIDI message from MIDI device

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Syntax

msgs = midireceive(device)
msgs = midireceive(device,maxmsgs)

Description

msgs = midireceive(device) returns the MIDI messages, msgs, received from a MIDI device using the MIDI device interface, device.

example

msgs = midireceive(device,maxmsgs) specifies the maximum number of MIDI messages to return as maxmsgs.

example

Examples

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To determine what MIDI devices are attached to your MIDI input ports, call mididevinfo. Use the availableDevices struct to specify a valid MIDI device to create a mididevice object.

availableDevices = mididevinfo;
device = mididevice(availableDevices.input(1).ID);

Once your MIDI device object is created, it begins listening to MIDI messages from your specified device and storing them in a buffer. To get all MIDI messages in the buffer, call midireceive. In this example, several keys on a MIDI keyboard are played.

msgs = midireceive(device)
msgs = 

  MIDI message:
    NoteOn          Channel: 1  Note: 52  Velocity: 64  Timestamp: 3.94  [ 90 34 40 ]
    NoteOn          Channel: 1  Note: 52  Velocity: 0   Timestamp: 4.179  [ 90 34 00 ]
    NoteOn          Channel: 1  Note: 48  Velocity: 64  Timestamp: 4.19  [ 90 30 40 ]
    NoteOn          Channel: 1  Note: 47  Velocity: 64  Timestamp: 4.382  [ 90 2F 40 ]
    NoteOn          Channel: 1  Note: 48  Velocity: 0   Timestamp: 4.459  [ 90 30 00 ]
    NoteOn          Channel: 1  Note: 48  Velocity: 64  Timestamp: 4.59  [ 90 30 40 ]
    NoteOn          Channel: 1  Note: 47  Velocity: 0   Timestamp: 4.776  [ 90 2F 00 ]
    NoteOn          Channel: 1  Note: 50  Velocity: 64  Timestamp: 4.788  [ 90 32 40 ]
    NoteOn          Channel: 1  Note: 47  Velocity: 64  Timestamp: 4.802  [ 90 2F 40 ]
    NoteOn          Channel: 1  Note: 52  Velocity: 64  Timestamp: 4.831  [ 90 34 40 ]
    NoteOn          Channel: 1  Note: 47  Velocity: 0   Timestamp: 4.84  [ 90 2F 00 ]
    NoteOn          Channel: 1  Note: 48  Velocity: 0   Timestamp: 4.912  [ 90 30 00 ]
    NoteOn          Channel: 1  Note: 52  Velocity: 0   Timestamp: 4.953  [ 90 34 00 ]
    NoteOn          Channel: 1  Note: 50  Velocity: 0   Timestamp: 5.079  [ 90 32 00 ]

Reading from the buffer clears the data. For example, if no more MIDI messages are sent, and the buffer is reread, midireceive returns an empty MIDI message.

msgs = midireceive(device)
msgs = 

  empty MIDI message array

Query your system for available output from MIDI devices. Specify that the output of a MIDI device is connected to the input of your mididevice object.

mididevinfo
  MIDI devices available:
  ID  Direction  Interface   Name
   0   output    MMSystem   'Microsoft MIDI Mapper'
   1    input    MMSystem   'USB MIDI Interface '
   2   output    MMSystem   'Microsoft GS Wavetable Synth'
   3   output    MMSystem   'USB MIDI Interface '
device = mididevice('Input','USB MIDI Interface ');

Once your MIDI device object is created, it begins listening to MIDI messages from your specified device and storing them in a buffer. To get a limited number of MIDI messages from the buffer, call midireceive and specify the maximum number of messages to return. In this example, five keys are played on a MIDI device. A maximum of four MIDI messages are received at each call to midireceive.

midireceive(device,4)
ans = 

  MIDI message:
    NoteOn          Channel: 1  Note: 36  Velocity: 64  Timestamp: 2929.71  [ 90 24 40 ]
    NoteOn          Channel: 1  Note: 36  Velocity: 0   Timestamp: 2929.91  [ 90 24 00 ]
    NoteOn          Channel: 1  Note: 37  Velocity: 64  Timestamp: 2930.43  [ 90 25 40 ]
    NoteOn          Channel: 1  Note: 37  Velocity: 0   Timestamp: 2930.59  [ 90 25 00 ]
midireceive(device,4)
ans = 

  MIDI message:
    NoteOn          Channel: 1  Note: 38  Velocity: 64  Timestamp: 2931.16  [ 90 26 40 ]
    NoteOn          Channel: 1  Note: 38  Velocity: 0   Timestamp: 2931.32  [ 90 26 00 ]
    NoteOn          Channel: 1  Note: 39  Velocity: 64  Timestamp: 2931.87  [ 90 27 40 ]
    NoteOn          Channel: 1  Note: 39  Velocity: 0   Timestamp: 2932.01  [ 90 27 00 ]
midireceive(device,4)
ans = 

  MIDI message:
    NoteOn          Channel: 1  Note: 40  Velocity: 64  Timestamp: 2932.52  [ 90 28 40 ]
    NoteOn          Channel: 1  Note: 40  Velocity: 0   Timestamp: 2932.66  [ 90 28 00 ]

Input Arguments

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Specify device as an object created by mididevice.

Maximum number of messages to return, specified as a positive integer scalar.

Data Types: single | double

Output Arguments

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Object of midimsg, returned as a scalar or column vector. The number of MIDI messages in the mididevice buffer and maxmsgs determine the size of msgs.

Version History

Introduced in R2018a

See Also

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