Open-source licences

Last updated 13 October 2026

CueLevel is built with open-source software. Thank you to the people who make it. Here is what’s included, its licence, and where to get its source.

FFmpeg

CueLevel runs FFmpeg 7.1 as a separate program inside the app (CueLevel.app/Contents/Resources/ffmpeg) to decode, measure, filter and write audio. It’s built from the official FFmpeg 7.1 source release with no changes to that source, with GPL and non-free components switched off and no external libraries.

Licence: GNU Lesser General Public License, version 2.1 or later. Read the LGPL 2.1.

Corresponding source: ffmpeg-7.1.tar.xz, the official source archive the engine is built from. From CueLevel 2.0.2 onwards, the exact archive and build configuration are also attached to every release on the CueLevel releases page.

Build configuration: ./configure --arch=arm64 --target-os=darwin --cc=clang --extra-cflags=-mmacosx-version-min=13.0 --extra-ldflags=-mmacosx-version-min=13.0 --enable-static --disable-shared --disable-gpl --disable-nonfree --disable-autodetect --enable-zlib --disable-doc --disable-ffplay --disable-ffprobe --disable-network --disable-debug

Written offer: for at least three years after you receive any version of CueLevel, we will send you a complete copy of the corresponding FFmpeg source code on request, for no more than the cost of providing it. Write to hello@cuelevel.com.

Because FFmpeg runs as its own program, you can replace Contents/Resources/ffmpeg with your own build of FFmpeg 7.1. The copy inside the app is covered by the app’s code signature, so macOS will treat a modified app as unsigned.

FFmpeg is a trademark of Fabrice Bellard, originator of the FFmpeg project. CueLevel isn’t affiliated with or endorsed by the FFmpeg project.

RNNoise speech model

CueLevel’s speech cleanup uses the original RNNoise model from Xiph.Org, in the format FFmpeg reads. Copyright Jean-Marc Valin, Amazon, Mozilla, the Xiph.Org Foundation and Mark Borgerding. Licensed under the BSD 3-clause licence. Read the licence.

Website fonts

Archivo by Omnibus-Type, under the SIL Open Font License 1.1. Read the licence.
Geist by Vercel, under the SIL Open Font License 1.1. Read the licence.

Inside the app

The same notices and full licence texts ship inside CueLevel, in CueLevel.app/Contents/Resources/Third-party notices. To open it, Control-click CueLevel in Finder, choose Show Package Contents, then open Contents › Resources.