
MIDI(4)                   OpenBSD Programmer's Manual                  MIDI(4)

NAME
     midi - device-independent MIDI driver layer

SYNOPSIS
     midi* at opl?
     midi* at pcppi?
     midi* at sb?
     midi* at wss?
     pseudo-device sequencer

     #include <sys/types.h>
     #include <sys/midiio.h>

DESCRIPTION
     The midi driver provides support for various MIDI peripherals.  It pro-
     vides a uniform programming interface layer above different underlying
     MIDI hardware drivers.  The MIDI hardware can be of many different kinds,
     e.g., an external synthesizer on a MIDI port (or a serial port), the PC
     speaker, an internal FM synth, or a wavetable synth.

     There are two device file types available for MIDI operation:
     /dev/rmidiN, and /dev/music. The /dev/rmidiN devices provides raw access
     to a MIDI device.  Data written is sent to the physical device as fast as
     possible and is uninterpreted.  Reading from the device returns data as
     soon as it becomes available.  A moderate amount of buffering is avail-
     able both for reading and writing.  The raw MIDI devices are mostly use-
     ful for non realtime operations, such as downloading patches to a device,
     since it is hard to get the accurate timing needed for quality music from
     a user program.  But the devices can act as a simple patchboard for MIDI
     devices.  For example, a MIDI keyboard could be connected to a synthesiz-
     er by the command

     cat -u /dev/rmidi1 >/dev/rmidi2

     The /dev/music device is a MIDI sequencer device.  Data sent to and from
     this device not only contains the information sent to the MIDI device,
     but also timing information.  The kernel will make sure that data is sent
     to the physical device at the indicated time.  The sequencer device uses
     the /dev/midiN devices internally and they are unavailable when used by
     the sequencer.

     The API for the sequencer device is binary compatible with the OSS se-
     quencer interface.

FILES
     /dev/rmidiN
     /dev/music
     /dev/sequencer

SEE ALSO
     midiplay(1), ioctl(2), ossaudio(3), audio(4), opl(4), pcppi(4), sb(4),
     wss(4)

HISTORY
     The midi driver first appeared in NetBSD 1.4.

BUGS
     This man page is very incomplete.

OpenBSD 3.0                     August 6, 1998                               1
