https://github.com/koppi/alsa-midi-latency-test
Measure the roundtrip delay of MIDI messages within the Advanced Linux© Sound Architecture (ALSA) subsystem
https://github.com/koppi/alsa-midi-latency-test
alsa audio jitter-analysis latency-test latency-tester linux midi midi-message
Last synced: 2 months ago
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Measure the roundtrip delay of MIDI messages within the Advanced Linux© Sound Architecture (ALSA) subsystem
- Host: GitHub
- URL: https://github.com/koppi/alsa-midi-latency-test
- Owner: koppi
- License: gpl-2.0
- Created: 2015-07-17T22:22:31.000Z (almost 11 years ago)
- Default Branch: master
- Last Pushed: 2025-12-23T21:48:20.000Z (6 months ago)
- Last Synced: 2025-12-25T11:38:37.879Z (6 months ago)
- Topics: alsa, audio, jitter-analysis, latency-test, latency-tester, linux, midi, midi-message
- Language: M4
- Homepage:
- Size: 541 KB
- Stars: 27
- Watchers: 4
- Forks: 7
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: COPYING
Awesome Lists containing this project
README
``alsa-midi-latency-test`` is a Linux©-based tool used to measure the roundtrip delay of MIDI messages within the ALSA (Advanced Linux© Sound Architecture) subsystem.
The tool utilizes a high-precision timer to calculate the time it takes for a MIDI message to travel from the ALSA source to the ALSA sink, and back. It's a helpful way to understand and troubleshoot MIDI latency issues, often in situations where noticeable delay is encountered between playing a MIDI keyboard and hearing the sound.
* **Roundtrip Measurement**
The tool measures the total time it takes for a MIDI message to complete a round trip, meaning from the output of one device to the input of another.
* **High-Precision Timer**
It uses a high-precision timer to accurately measure the delay, which is crucial for precise latency measurements.
* **ALSA Subsystem Focus**
The tool specifically focuses on the ALSA subsystem, allowing users to diagnose latency issues related to Linux's© audio/MIDI infrastructure.
How alsa-midi-latency-test can help:
* **Diagnosing MIDI Latency**
The tool can help users pinpoint the source of latency, whether it's related to the MIDI hardware, software drivers, or system configuration.
* **Optimizing ALSA Settings**
The measurements can guide users in adjusting ALSA settings, such as buffer sizes, to minimize latency.
* **Identifying System Bottlenecks**
In some cases, latency can be a result of system limitations, and ``alsa-midi-latency-test`` can help identify those bottlenecks.
In summary, ``alsa-midi-latency-test`` is a valuable tool for anyone working with MIDI and ALSA on Linux©, allowing them to measure and troubleshoot latency issues effectively.
## Install from source code
```shell
git clone https://github.com/koppi/alsa-midi-latency-test.git
cd alsa-midi-latency-test/
```
The following packages are required to build alsa-midi-latency-test:
```shell
sudo apt -y install debhelper autotools-dev automake libasound2-dev
```
Compile alsa-midi-latency-test as follows:
```shell
sh autogen.sh
./configure
make
```
Install alsa-midi-latency-test as follows:
```shell
sudo make install
```
or build and install a Debian / Ubuntu package:
```shell
sudo apt -y install devscripts
debuild -uc -us
sudo dpkg -i ../alsa-midi-latency-test*.deb
```
## Run alsa-midi-latency-test
* ``` alsa-midi-latency-test -l ```
Lists available MIDI input and output ports.
* ``` alsa-midi-latency-test -i [input port] -o [output port] ```
This runs the benchmark with the given input and output port. Note, that the
input and output ports have to be connected using a MIDI cable in the real
hardware to loop the MIDI message back.
* ``` man alsa-midi-latency-test ```
The man page contains documentation for all available command line switches.
### Benchmarking Results
Please share your results in the [Wiki](../../wiki/).
### Definitions
* [Wikipedia EN - Latency in engineering](http://tinyurl.com/wikipedia-latency-engineering)
* [Wikipedia EN - Latency with audio](http://tinyurl.com/wikipedia-latency-audio)
## See also
* http://lists.linuxaudio.org/listinfo/linux-audio-tuning
The linux-audio tuning (LAT) mailing list is to help GNU/Linux© distribution
maintainers and other interested users to share information on system
performance tuning matters, especially with regard to real-time Linux©
kernels.
* http://www.alsa-project.org
The Advanced Linux© Sound Architecture.
* [http://www.evc-soft.nl/evc/products/miditest](http://web.archive.org/web/20061128213256/http://www.evc-soft.nl/evc/products/miditest)
The MidiTest software for Microsoft Windows.
* https://codeberg.org/rtcqs/rtcqs
rtcqs is a Python utility to analyze your system and detect possible bottlenecks that could have a negative impact on the performance of your system when working with Linux© audio.
## Thanks to
* [Arnout Engelen](https://github.com/raboof) for initial testing,
* [Clemens Ladisch](https://github.com/cladisch) for a number of fixes with the high precision timer and ALSA midi event handling,
* [Giulio Moro](https://github.com/giuliomoro) for code cleanup, various fixes and support for UART I/O.
## BUGS and AUTHORS
Please [report bugs](https://github.com/koppi/alsa-midi-latency-test/issues) to the authors:
* [Jakob Flierl](https://github.com/koppi)
Last updated Apr 2026.