OpenMeters

Professional, fast, and open-source audio meters for Linux.

Capture any PipeWire application or device, inspect loudness, frequency, waveform, and stereo image in one comprehensive suite.

Quick links

• Features
• Installation
  • Arch Linux
  • Debian
  • Fedora
  • NixOS
  • Build from source
• Usage and key bindings
• Configuration and theming
• Frequently Asked Questions
• Contributing
• Credits
• License

Features

Everything below describes behavior implemented thus far. If you have ideas for the next thing OpenMeters should do, please feel free to open an issue or pull request.

General

• PipeWire audio capture
  • Per-application capture.
  • Direct device/default-sink capture with negotiated layouts of up to eight channels.
• Windowing
  • Normal desktop windows on X11 or Wayland.
  • Wayland layer-shell "bar mode" when the compositor exposes zwlr_layer_shell_v1, anchored to the top or bottom of a given monitor.
  • Pop-out windows for individual visuals.
  • Configurable 30, 60, 120 FPS, or vertical-synced frame cadence.
  • Window decoration toggle.
• Appearance and persistence
  • Configurable RGBA background color.
  • Editable JSON settings with lossy loading for unknown or invalid fields.
  • User themes.

Visuals

• Loudness
  • BS.1770-5 K-weighted short-term and momentary LUFS meter modes.
  • True Peak meter modes.
  • Fast and slow K-weighted RMS dB meter modes.
• Oscilloscope
  • Selectable left, right, mid/mono, side, or none channel traces.
  • Selectable trigger source, including channel-dependent triggering for independently stable traces.
  • A stable waveform trigger that uses autocorrelation period estimation and waveform template correlation. (Often referred to as "pitch-following" or "phase-locking" in other applications.)
  • Selectable cycle count in stable trigger mode.
  • Zero-crossing trigger for traditional scope behavior.
• Spectrogram
  • A multitude of window types, lengths, and hop sizes.
  • Classic STFT rendering.
  • Time-frequency reassignment (Similar to Wavecandy's "Enhanced frequency" mode, or MiniMeters' "Sharper" mode.)
  • Click-and-hold crosshair with frequency, note, and time tooltip.
  • Piano-roll overlay.
  • Frequency-axis zoom and pan.
  • ERB, logarithmic, and linear frequency scales.
  • Adjustable color map, stop positions, and stop spreads.
• Spectrum analyzer
  • A multitude of window types, lengths, and hop sizes.
  • Selectable primary and secondary source: left, right, mid, side, or none.
  • Raw or IEC 61672-1 A-weighted display.
  • Peak label with frequency, note, and level.
  • No averaging, exponential averaging, or peak hold.
  • ERB, logarithmic, and linear frequency scales.
  • Line or bar display with adjustable color map.
• Stereometer
  • L/R vector display in Lissajous or dot-cloud modes.
  • Frequency-band dot-cloud mode with low/mid/high bands.
  • Single-band or low/mid/high phase-correlation meter.
  • Adjustable correlation window.
  • Adjustable dot-cloud scale, rotation, channel flip, unipolar fold, dot size, and grid.
• Waveform
  • Selectable left, right, mid/mono, side, or none channel lanes.
  • Adjustable scroll speed.
  • Optional low/mid/high band-level history overlay.
  • Color by low/mid/high band balance, loudness, or a static color.

Installation

Prerequisites

OpenMeters requires:

1. A graphical Linux session on X11 or Wayland.
2. PipeWire 0.3.77 or newer, installed and running.
3. Vulkan support through your distribution's Vulkan loader and driver stack.
4. For pre-built release artifacts: x86_64 GNU/Linux with glibc >= v2.39. The release workflow builds these artifacts in Ubuntu 24.04.

Normal application windows are available on both X11 and Wayland. Bar mode additionally requires a Wayland compositor that exposes zwlr_layer_shell_v1.

Arch Linux

Install the openmeters-git package from the AUR:

yay -S openmeters-git

Debian

Download the latest .deb package from GitHub Releases.

Fedora

Download the latest .rpm package from GitHub Releases.

NixOS

OpenMeters is available in nixpkgs thanks to @magnetophon and @bitbloxhub. Add it to your nix config with:

nix profile add nixpkgs#openmeters

Other distributions

Tarballs are available under tagged releases, or you can build OpenMeters from source. I cannot guarantee OpenMeters will work on every distribution, although it is designed to stay fairly distro-agnostic. If you have trouble getting it running, please open an issue and I will try to help.

Building from source

1. Install a Rust toolchain, a C toolchain, pkg-config, libclang, and native development packages for PipeWire, Wayland/X11, xkbcommon, fontconfig/freetype, and the Vulkan loader/development headers. PipeWire/SPA development headers must be from PipeWire 0.3.77 or newer. The recommended way to install Rust is rustup. OpenMeters currently requires the Rust version declared in Cargo.toml or newer.

2. Clone the repository:

   git clone https://github.com/httpsworldview/openmeters/
   cd openmeters
   

3. Build and run the release binary:

   cargo build --release
   ./target/release/openmeters
   

   Or run it directly through Cargo:

   cargo run --release
   

Packaging

See packaging/ for instructions on building Debian, Fedora, and tarball artifacts.

Usage and key bindings

Global

Spectrogram

Configuration

On first launch, all six visuals are enabled and docked in this order: spectrogram, spectrum analyzer, waveform, oscilloscope, stereometer, and loudness. Refresh follows the main display. Bar mode defaults to 100px high at the bottom edge on supported Wayland compositors; other desktops use a normal window. Saved settings, including disabled visuals, take precedence over these defaults.

Application settings are saved to $XDG_CONFIG_HOME/openmeters/settings.json, or to:

~/.config/openmeters/settings.json

when XDG_CONFIG_HOME is unset.

settings.json is intentionally editable. GUI ranges are not hard limits; processors normalize only the bare minimum necessary for runtime. Unsupported keys or structurally invalid values are logged and ignored at the narrowest practical scope.

Invalid JSON syntax is ignored and default settings are used for that run. Your configuration file will not be overwritten unless you explicitly change settings in the GUI. Window resize notifications and device discovery alone do not authorize replacing that file. Other read errors receive the same protection; a missing file can be created normally. Unknown keys are not preserved when the file is next written.

If a bug causes OpenMeters to misbehave, you can reset application settings by deleting settings.json. Please consider reporting the bug if you run into this.

Theming

Themes are saved as separate JSON files in $XDG_CONFIG_HOME/openmeters/themes/, or in:

~/.config/openmeters/themes/

when XDG_CONFIG_HOME is unset. Theme files own palettes and background color; settings.json stores the selected theme name and non-palette module settings.

You can create and switch between themes in the Appearance section of the configuration page. Saving a theme refreshes the list of available themes, including any files that appeared in the theme directory while OpenMeters was running. The built-in theme is read-only in the UI and cannot be overwritten. Feel free to share custom themes by sharing the corresponding JSON files.

Frequently Asked Questions

Q: Can I build upon OpenMeters or use it in a commercial application?

A: Yes, as long as you abide by the terms of the GPL. My primary focus is keeping OpenMeters free and open source, not profiting from it.

Q: Will you support Windows or macOS?

A: Maybe, but probably not. I'm a Linux user and have been for most of my life. I am not currently confident in my ability to maintain reliable support for either platform. That said, I aim to keep things modular and platform-agnostic where possible. The DSP code at the core of this project will run anywhere; the GUI, persistence, and audio backend code will not.

Q: Why is OpenMeters' FFT size about twice the value shown in MiniMeters or Wave Candy?

A: OpenMeters labels FFT/window size by the number of input samples used. MiniMeters and Wave Candy instead label the visible positive-frequency bins, which represent roughly half the FFT for real-valued audio. To match settings, use approximately twice their displayed band count (for example, 2048 in MiniMeters corresponds to 4096 in OpenMeters).

Contributing

Please see CONTRIBUTING.md for guidelines on how to contribute and how to get started. No matter what you have to offer, I greatly appreciate your interest in the project. Every bit helps.

Reuse and license

OpenMeters is GPL-3.0-or-later software. You may reuse code under the GPL's terms. If you want to discuss other arrangements or have licensing questions, feel free to email me at httpworldview@gmail.com. You are also free to draw inspiration from the ideas and methods used here, provided you respect the GPL.

It would be unfair to ask for attribution over ideas alone when this project exists thanks to the countless researchers and open-source contributors who came before me.

Credits

Thank you for checking out OpenMeters. If you think it is useful, please consider starring the repository and sharing it with others. I appreciate criticism, bug reports, and feedback, so feel free to reach out.

Projects

• MiniMeters (https://minimeters.app/) inspired this project. If you can, please support their work.
• Corrscope (https://github.com/corrscope/corrscope) was a key reference for correlation-triggered oscilloscope stability.
• EasyEffects (https://github.com/wwmm/easyeffects) has been a valuable reference for PipeWire integration and audio processing.
• Ardura's Scrolloscope (https://github.com/ardura/Scrollscope)
• Tim Strasser's Oszilloskop (https://github.com/timstr/oszilloskop)
• Audacity (https://www.audacityteam.org/)
• FFmpeg (https://ffmpeg.org/)
• libebur128 (https://github.com/jiixyj/libebur128), the original C library for EBU R 128 loudness measurement.
• BBC's audiowaveform (https://github.com/bbc/audiowaveform)
• librosa (https://librosa.org/)

Papers and Standards

• ITU-R BS.1770-5, loudness and true peak measurement.
• IEC 61672-1, A-weighting reference curve.
• Brecht De Man, "Evaluation of Implementations of the EBU R128 Loudness Measurement", 145th Audio Engineering Society Convention, paper 10064, October 2018.
• A. de Cheveigné and H. Kawahara, "YIN, a fundamental frequency estimator for speech and music".
  • Historically, the algorithm within this paper was implemented by our oscilloscope.
• F. Auger and P. Flandrin, "Improving the readability of time-frequency and time-scale representations by the reassignment method".
• K. Kodera, R. Gendrin, and C. de Villedary, "Analysis of time-varying signals with small BT values".
• S. Fulop and K. Fitz, "Algorithms for computing the time-corrected instantaneous frequency (reassigned) spectrogram, with applications".

Libraries

• iced_exwlshell and related crates (https://github.com/waycrate/exwlshelleventloop)
  • Special thanks to Decodetalkers for reviewing and merging my patches, and for maintaining such a useful library.
• Iced (https://github.com/iced-rs/iced)
• RustFFT (https://github.com/ejmahler/RustFFT)
• RealFFT (https://github.com/HEnquist/realfft)
• wgpu (https://github.com/gfx-rs/wgpu)

License

OpenMeters is licensed under the GNU General Public License v3.0 or later. See LICENSE for more details.