x42 / jack_midi_latency

Utility to measure jackaudio MIDI latency & jitter

JACK MIDI LATENCY TEST

A small utility that measures round-trip latency of JACK MIDI events.

Usage

Use a cable to close the loop: physically connect MIDI-out of the soundcard to MIDI-in of the soundcard.

Start jack_midi_latency on a terminal and connect its jack-ports to the corresponding harware ports.

See Also

ALSA sequencer latency test

jack_midi_latency's Issues

No signal despite closed loop

Thank you very much for providing a midi latency measurement tool which uses jack.

I have an "M-Audio MIDIsport 1x1 USB" and I'd like to measure the latency. I already did that successfully using this tool:
https://github.com/koppi/alsa-midi-latency-test

Then I tried it using the jack_midi_latency tool but it didn't work.
Here is my setup:

1. I have a midi keyboard connected via USB to my laptop
2. I have the M-Audio Interface connected to my laptop, the loop is closed
3. jackd is running, audio playback works.
4. Midi <-> jack connection is provided by "a2jmidid"
5. I route Midi-keyboard -> M-Audio and M-Audio -> GrandOrgue just to see if everything works as expected. It does, when I press a key I get an organ sound.
6. I run jack_midi_latency and connect it to the M-Audio. It complains that it gets no signal, but the "midi out" LED on the M-Audio turns on permanently while the "midi in" LED stays dark. The virtual organ continues to work as expected.

My kernel: 4.13.0-1-amd64 #1 SMP Debian 4.13.4-2 (2017-10-15) x86_64 GNU/Linux