midi - Pygame Documentation

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pygame.midi

pygame module for interacting with midi input and output.

pygame.midi.Input - Input is used to get midi input from midi devices.	Input is used to get midi input from midi devices.
pygame.midi.MidiException - exception that pygame.midi functions and classes can raise	exception that pygame.midi functions and classes can raise
pygame.midi.Output - Output is used to send midi to an output device	Output is used to send midi to an output device
pygame.midi.get_count - gets the number of devices.	gets the number of devices.
pygame.midi.get_default_input_id - gets default input device number	gets default input device number
pygame.midi.get_default_output_id - gets default output device number	gets default output device number
pygame.midi.get_device_info - returns information about a midi device	returns information about a midi device
pygame.midi.init - initialize the midi module	initialize the midi module
pygame.midi.midis2events - converts midi events to pygame events	converts midi events to pygame events
pygame.midi.quit - uninitialize the midi module	uninitialize the midi module
pygame.midi.time - returns the current time in ms of the PortMidi timer	returns the current time in ms of the PortMidi timer

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

Including real midi devices, and virtual ones.

It uses the portmidi library. Is portable to which ever platforms portmidi supports (currently windows, OSX, 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.Input

Input is used to get midi input from midi devices.
Input(device_id)
Input(device_id, buffer_size)

Input.close - closes a midi stream, flushing any pending buffers.	closes a midi stream, flushing any pending buffers.
Input.poll - returns true if there's data, or false if not.	returns true if there's data, or false if not.
Input.read - reads num_events midi events from the buffer.	reads num_events midi events from the buffer.

buffer_size -the number of input events to be buffered waiting to

  be read using Input.read()

Input.close

closes a midi stream, flushing any pending buffers.

Input.close(): return None

PortMidi attempts to close open streams when the application exits -- this is particularly difficult under Windows.

Input.poll

returns true if there's data, or false if not.

Input.poll(): return Bool

raises a MidiException on error.

Input.read

reads num_events midi events from the buffer.

Input.read(num_events): return midi_event_list

Reads from the Input buffer and gives back midi events. [[[status,data1,data2,data3],timestamp],

 [[status,data1,data2,data3],timestamp],...]

pygame.midi.MidiException

exception that pygame.midi functions and classes can raise

MidiException(errno)

pygame.midi.Output

Output is used to send midi to an output device
Output(device_id)
Output(device_id, latency = 0)
Output(device_id, buffer_size = 4096)
Output(device_id, latency, buffer_size)

Output.abort - terminates outgoing messages immediately	terminates outgoing messages immediately
Output.close - closes a midi stream, flushing any pending buffers.	closes a midi stream, flushing any pending buffers.
Output.note_off - turns a midi note off. Note must be on.	turns a midi note off. Note must be on.
Output.note_on - turns a midi note on. Note must be off.	turns a midi note on. Note must be off.
Output.set_instrument - select an instrument, with a value between 0 and 127	select an instrument, with a value between 0 and 127
Output.write - writes a list of midi data to the Output	writes a list of midi data to the Output
Output.write_short - write_short(status <, data1><, data2>)	write_short(status <, data1><, data2>)
Output.write_sys_ex - writes a timestamped system-exclusive midi message.	writes a timestamped system-exclusive midi message.

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. (NOTE: time is measured relative to the time source indicated by time_proc. Timestamps are absolute, not relative delays or offsets.) 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.

Output.abort

terminates outgoing messages immediately

Output.abort(): return None

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.

Output.close

closes a midi stream, flushing any pending buffers.

Output.close(): return None

PortMidi attempts to close open streams when the application exits -- this is particularly difficult under Windows.

Output.note_off

turns a midi note off. Note must be on.

Output.note_off(note, velocity=None, channel = 0)

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

Output.note_on

turns a midi note on. Note must be off.

Output.note_on(note, velocity=None, channel = 0)

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

Output.set_instrument

select an instrument, with a value between 0 and 127

Output.set_instrument(instrument_id, channel = 0)

Output.write

writes a list of midi data to the Output

Output.write(data)

writes series of MIDI information in the form of a list:

     write([[[status <,data1><,data2><,data3>],timestamp],
            [[status <,data1><,data2><,data3>],timestamp],...])

fields are optional example: choose program change 1 at time 20000 and send note 65 with velocity 100 500 ms later.

     write([[[0xc0,0,0],20000],[[0x90,60,100],20500]])

notes:

  1. timestamps will be ignored if latency = 0.
  2. To get a note to play immediately, send MIDI info with
     timestamp read from function Time.
  3. understanding optional data fields:
       write([[[0xc0,0,0],20000]]) is equivalent to
       write([[[0xc0],20000]])

Can send up to 1024 elements in your data list, otherwise an

 IndexError exception is raised.

Output.write_short

write_short(status <, data1><, data2>)

Output.write_short(status)

Output.write_short(status, data1 = 0, data2 = 0)

output MIDI information of 3 bytes or less. data fields are optional status byte could be:

     0xc0 = program change
     0x90 = note on
     etc.
     data bytes are optional and assumed 0 if omitted

example: note 65 on with velocity 100

     write_short(0x90,65,100)

Output.write_sys_ex

writes a timestamped system-exclusive midi message.

Output.write_sys_ex(when, msg)

msg - can be a *list* or a *string* when - a timestamp in miliseconds example:

  (assuming o is an onput MIDI stream)
    o.write_sys_ex(0,'\xF0\x7D\x10\x11\x12\x13\xF7')
  is equivalent to
    o.write_sys_ex(pygame.midi.time(),
                   [0xF0,0x7D,0x10,0x11,0x12,0x13,0xF7])

pygame.midi.get_count

gets the number of devices.

pygame.midi.get_count(): return num_devices

Device ids range from 0 to get_count() -1

pygame.midi.get_default_input_id

gets default input device number

pygame.midi.get_default_input_id(): return default_id

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

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

    set PM_RECOMMENDED_INPUT_DEVICE=1

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, and with USB devices that can come and go, using integers is not very reliable for device identification. Under Windows, if PM_RECOMMENDED_OUTPUT_DEVICE (or PM_RECOMMENDED_INPUT_DEVICE) is *NOT* found in the environment, then the default device is obtained by looking for a string in the registry under:

    HKEY_LOCAL_MACHINE/SOFTWARE/PortMidi/Recommended_Input_Device

and HKEY_LOCAL_MACHINE/SOFTWARE/PortMidi/Recommended_Output_Device for a string. 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. Examples are MMSystem, DirectX (not implemented), ALSA, OSS (not implemented), etc.) At present, the only Win32 interface is "MMSystem", the only Linux interface is "ALSA", and the only Max OS X interface is "CoreMIDI". To specify both the interface and the device name in the registry, separate the two with a comma and a space, e.g.:

    MMSystem, In USB MidiSport 1x1

In this case, 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.

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

pygame.midi.get_default_output_id

gets default output device number

pygame.midi.get_default_output_id(): return default_id

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

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

    set PM_RECOMMENDED_OUTPUT_DEVICE=1

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

    HKEY_LOCAL_MACHINE/SOFTWARE/PortMidi/Recommended_Input_Device

    MMSystem, In USB MidiSport 1x1

In this case, 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.

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

pygame.midi.get_device_info

returns information about a midi device

pygame.midi.get_device_info(an_id): return (interf, name, input, output, opened)

interf - a text string describing the device interface, eg 'ALSA'. name - a text string for the name of the device, eg 'Midi Through Port-0' input - 0, or 1 if the device is an input device. output - 0, or 1 if the device is an output device. opened - 0, or 1 if the device is opened.

If the id is out of range, the function returns None.

pygame.midi.init

initialize the midi module

pygame.midi.init(): return None

Call the initialisation function before using the midi module.

It is safe to call this more than once.

pygame.midi.midis2events

converts midi events to pygame events

pygame.midi.midis2events(midis, device_id): return [Event, ...]

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

pygame.midi.quit

uninitialize the midi module

pygame.midi.quit(): return None

Called automatically atexit if you don't call it.

It is safe to call this function more than once.

pygame.midi.time

returns the current time in ms of the PortMidi timer

pygame.midi.time(): return time

The time is reset to 0, when the module is inited.