arecordmidi
Record MIDI data from a MIDI port
SYNOPSIS
arecordmidi [-hV] [-l] [-p name] [-d #] [-r #] [-f file] port0 [port1 ...]
PARAMETERS
-h, --help
Print usage summary and exit
-V, --version
Print version information
-l, --list
List all available ALSA sequencer ports
-p, --port=NAME
Specify sequencer port name (overrides first argument)
-d, --duration=#
Record for specified seconds, then exit
-r, --rate=#
Set MIDI clock rate in Hz (default: 1000)
-f, --file=FILE
Output file path (default: arecordmidi-N.midi)
DESCRIPTION
arecordmidi is a command-line utility from the alsa-utils package used to record MIDI events from ALSA sequencer ports into standard MIDI files (SMF format 0 or 1). It runs in the background, capturing real-time MIDI input from devices like keyboards, controllers, or software synths routed through ALSA's sequencer.
Primarily useful for capturing live performances, debugging MIDI streams, or archiving sequences for later playback with aplaymidi. It supports multiple ports and automatic file naming. Recording starts immediately upon invocation and stops via SIGINT (Ctrl+C), timeout with -d, or when stdin closes.
The tool handles MIDI clock rates and verbose logging for detailed event tracking. Output files include headers for tempo, time signature, and track data, ensuring compatibility with most MIDI software. It's lightweight, non-interactive, and ideal for scripts or automated capture in Linux audio workflows.
CAVEATS
Records until interrupted (Ctrl+C) if no -d specified; requires ALSA sequencer access; multi-port recording multiplexes tracks; SMF format may split multi-channel input into format 1.
PORT NAMING
Ports follow 'hw:X,Y' or client:port syntax; use aseqdump -l or -l for discovery.
Example: hw:2,0 for second card's first port.
USAGE EXAMPLE
arecordmidi -p hw:1,0 -d 30 -f session.mid
Records 30 seconds from hw:1,0 to session.mid.
HISTORY
Developed as part of ALSA utilities around 2002 (alsa-lib 1.0 era); maintained in alsa-utils package for Linux kernels with ALSA support; minor updates for sequencer API changes in ALSA 1.0+.
