pygame module for interacting with midi input and output.

The midi module can send output to midi devices and get input from midi devices. It can also list midi devices on the system.

The midi module supports real and virtual midi devices.

It uses the portmidi library. Is portable to which ever platforms portmidi supports (currently Windows, Mac OS X, and Linux).

This uses pyportmidi for now, but may use its own bindings at some point in the future. The pyportmidi bindings are included with pygame.

New in pygame 1.9.0.

pygame.midi.init() -> None

initialize the midi module

Initializes the pygame.midi module. Must be called before using the pygame.midi module.

It is safe to call this more than once.

pygame.midi.quit() -> None

uninitialize the midi module

Uninitializes the pygame.midi module. If pygame.midi.init() was called to initialize the pygame.midi module, then this function will be called automatically when your program exits.

It is safe to call this function more than once.

pygame.midi.get_init() -> bool

returns True if the midi module is currently initialized

Gets the initialization state of the pygame.midi module.

Returns: True if the pygame.midi module is currently initialized.
Return type: bool

New in pygame 1.9.5.


Input is used to get midi input from midi devices.
Input(device_id) -> None
Input(device_id, buffer_size) -> None
  • device_id (int) -- midi device id
  • buffer_size (int) -- (optional) the number of input events to be buffered

close() -> None

closes a midi stream, flushing any pending buffers.

PortMidi attempts to close open streams when the application exits.


This is particularly difficult under Windows.

poll() -> bool

returns True if there's data, or False if not.

Used to indicate if any data exists.

Returns: True if there is data, False otherwise
Return type: bool
Raises: MidiException -- on error

read(num_events) -> midi_event_list

reads num_events midi events from the buffer.

Reads from the input buffer and gives back midi events.

Parameters: num_events (int) -- number of input events to read
Returns: the format for midi_event_list is [[[status, data1, data2, data3], timestamp], ...]
Return type: list


Output is used to send midi to an output device
Output(device_id) -> None
Output(device_id, latency=0) -> None
Output(device_id, buffer_size=4096) -> None
Output(device_id, latency, buffer_size) -> None

The buffer_size specifies the number of output events to be buffered waiting for output. In some cases (see below) PortMidi does not buffer output at all and merely passes data to a lower-level API, in which case buffersize is ignored.

latency is the delay in milliseconds applied to timestamps to determine when the output should actually occur. If latency is <<0, 0 is assumed.

If latency is zero, timestamps are ignored and all output is delivered immediately. If latency is greater than zero, output is delayed until the message timestamp plus the latency. In some cases, PortMidi can obtain better timing than your application by passing timestamps along to the device driver or hardware. Latency may also help you to synchronize midi data to audio data by matching midi latency to the audio buffer latency.


Time is measured relative to the time source indicated by time_proc. Timestamps are absolute, not relative delays or offsets.

abort() -> None

terminates outgoing messages immediately

The caller should immediately close the output port; this call may result in transmission of a partial midi message. There is no abort for Midi input because the user can simply ignore messages in the buffer and close an input device at any time.

close() -> None

closes a midi stream, flushing any pending buffers.

PortMidi attempts to close open streams when the application exits.


This is particularly difficult under Windows.

note_off(note, velocity=None, channel=0) -> None

turns a midi note off (note must be on)

Turn a note off in the output stream. The note must already be on for this to work correctly.

note_on(note, velocity=None, channel=0) -> None

turns a midi note on (note must be off)

Turn a note on in the output stream. The note must already be off for this to work correctly.

set_instrument(instrument_id, channel=0) -> None

select an instrument, with a value between 0 and 127

Select an instrument.

set_instrument(value=0, channel=0) -> None

modify the pitch of a channel.

Adjust the pitch of a channel. The value is a signed integer from -8192 to +8191. For example, 0 means "no change", +4096 is typically a semitone higher, and -8192 is 1 whole tone lower (though the musical range corresponding to the pitch bend range can also be changed in some synthesizers).

If no value is given, the pitch bend is returned to "no change".

New in pygame 1.9.4.

write(data) -> None

writes a list of midi data to the Output

Writes series of MIDI information in the form of a list.

Parameters: data (list) -- data to write, the expected format is [[[status, data1=0, data2=0, ...], timestamp], ...] with the data# fields being optional
Raises: IndexError -- if more than 1024 elements in the data list


# Program change at time 20000 and 500ms later send note 65 with
# velocity 100.
write([[[0xc0, 0, 0], 20000], [[0x90, 60, 100], 20500]])


  • Timestamps will be ignored if latency = 0
  • To get a note to play immediately, send MIDI info with timestamp read from function Time
  • Optional data fields: write([[[0xc0, 0, 0], 20000]]) is equivalent to write([[[0xc0], 20000]])

write_short(status) -> None
write_short(status, data1=0, data2=0) -> None

writes up to 3 bytes of midi data to the Output

Output MIDI information of 3 bytes or less. The data fields are optional and assumed to be 0 if omitted.

Examples of status byte values:

0xc0  # program change
0x90  # note on
# etc.


# note 65 on with velocity 100
write_short(0x90, 65, 100)

write_sys_ex(when, msg) -> None

writes a timestamped system-exclusive midi message.

Writes a timestamped system-exclusive midi message.

  • msg (list[int] or str) -- midi message
  • when -- timestamp in milliseconds


midi_output.write_sys_ex(0, '\xF0\x7D\x10\x11\x12\x13\xF7')

# is equivalent to

                         [0xF0, 0x7D, 0x10, 0x11, 0x12, 0x13, 0xF7])

get_count() -> num_devices

gets the number of devices.

Device ids range from 0 to get_count() - 1

get_default_input_id() -> default_id

gets default input device number

The following describes the usage details for this function and the get_default_output_id() function.

Return the default device ID or -1 if there are no devices. The result can be passed to the Input/Output class.

On a PC the user can specify a default device by setting an environment variable. To use device #1, for example:


The user should first determine the available device ID by using the supplied application "testin" or "testout".

In general, the registry is a better place for this kind of info. With USB devices that can come and go, using integers is not very reliable for device identification. Under Windows, if PM_RECOMMENDED_INPUT_DEVICE (or PM_RECOMMENDED_OUTPUT_DEVICE) is NOT found in the environment, then the default device is obtained by looking for a string in the registry under:


The number of the first device with a substring that matches the string exactly is returned. For example, if the string in the registry is "USB" and device 1 is named "In USB MidiSport 1x1", then that will be the default input because it contains the string "USB".

In addition to the name, get_device_info() returns "interf", which is the interface name. The "interface" is the underlying software system or API used by PortMidi to access devices. Supported interfaces:

MMSystem   # the only Win32 interface currently supported
ALSA       # the only Linux interface currently supported
CoreMIDI   # the only Mac OS X interface currently supported
# DirectX - not implemented
# OSS     - not implemented

To specify both the interface and the device name in the registry, separate the two with a comma and a space. The string before the comma must be a substring of the "interf" string and the string after the space must be a substring of the "name" name string in order to match the device. e.g.:

MMSystem, In USB MidiSport 1x1


In the current release, the default is simply the first device (the input or output device with the lowest PmDeviceID).

get_default_output_id() -> default_id

gets default output device number

See get_default_input_id() for usage details.

get_device_info(an_id) -> (interf, name, input, output, opened)
get_device_info(an_id) -> None

returns information about a midi device

Gets the device info for a given id.

Parameters: an_id (int) -- id of the midi device being queried
Returns: if the id is out of range None is returned, otherwise a tuple of (interf, name, input, output, opened) is returned.
  • interf: string describing the device interface (e.g. 'ALSA')
  • name: string name of the device (e.g. 'Midi Through Port-0')
  • input: 1 if the device is an input device, otherwise 0
  • output: 1 if the device is an output device, otherwise 0
  • opened: 1 if the device is opened, otherwise 0
Return type: tuple or None

midis2events(midis, device_id) -> [Event, ...]

converts midi events to pygame events

Takes a sequence of midi events and returns list of pygame events.

time() -> time

returns the current time in ms of the PortMidi timer

The time is reset to 0 when the pygame.midi module is initialized.

frequency_to_midi(midi_note) -> midi_note

Converts a frequency into a MIDI note. Rounds to the closest midi note.


frequency_to_midi(27.5) == 21

New in pygame 1.9.5.

midi_to_frequency(midi_note) -> frequency

Converts a midi note to a frequency.


midi_to_frequency(21) == 27.5

New in pygame 1.9.5.

midi_to_ansi_note(midi_note) -> ansi_note

Returns the Ansi Note name for a midi number.


midi_to_ansi_note(21) == 'A0'

New in pygame 1.9.5.

MidiException(errno) -> None

exception that pygame.midi functions and classes can raise

Edit on GitHub

© Pygame Developers.
Licensed under the GNU LGPL License version 2.1.