Releases and source
Open source
Auralyn includes FFmpeg, which is open source. Here is exactly which FFmpeg, where its source is, and how to get a copy from us.
What this page covers
Auralyn is our own software, and its code is ours. A few parts of it come from open-source projects. Their licences let us ship them as long as we credit them and make their source available to everyone who gets Auralyn.
Two of those parts are built from FFmpeg, the open-source library for reading audio and video. FFmpeg is licensed under the LGPL (the GNU Lesser General Public License, version 2.1 or later), which asks for the complete source of the library, a way to get it, and the freedom to swap in a changed copy. This page gives all three. It covers those libraries only: the rest of Auralyn is not open source.
Before the first release
Auralyn 1.0 is in development. The versions below are the ones in the current development build (26 October 2026). From the first release, each version's release notes link here, and the source kit for that version is published on this page.
The FFmpeg helper
Auralyn for Mac includes two small programs, ffmpeg and ffprobe, which it starts on its own to open files and tracks the built-in player cannot, such as some audio formats, extra audio tracks and embedded subtitles. They are built by us from FFmpeg with two small patches of ours.
| Built from | FFmpeg 9.0.2, tag n9.0.2, commit 946fcce07b6dcd0331c8cc609192aeff5e1924f8 |
|---|---|
| Our changes | Two patches, to libavcodec/hevc/parser.c and libavformat/demux.c. They help FFmpeg read the timing of HEVC video in MKV files. They add no decoder. |
| Licence | LGPL version 2.1 or later. Built with no GPL, version 3 or nonfree option and no outside codec library. |
| Source | FFmpeg at that commit: git.ffmpeg.org. The source kit with our two patches, the exact build settings and the build script is published here with the first release, and is available now on request (below). |
Audio in AC-3 and E-AC-3 (Dolby Digital and Dolby Digital Plus) is decoded by Apple's AudioToolbox, which is part of macOS, not by FFmpeg's own decoders. FFmpeg is a trademark of Fabrice Bellard, originator of the FFmpeg project.
FFmpeg in the Electron runtime
Auralyn is built on Electron, which brings its own copy of Chromium, the engine behind Google Chrome. Chromium plays audio and video with a library built from FFmpeg, libffmpeg.dylib. Auralyn ships Electron's own build of it unchanged; only the code signature is ours.
| Runtime | Electron 44.9.3 for macOS on Apple silicon, Chromium 152.0.7977.167 |
|---|---|
| Library | libffmpeg.dylib, 2,317,968 bytes as Electron distributes it, SHA-256 a2191fee07fd3deea6fd8a9823937a7ae510d1754ccbaa895b3d417e4c3f4958 |
| Licence | LGPL version 2.1 or later |
| Source | Chromium's FFmpeg at commit 2b68d2babae73714846961fb0ee47e3b3d2e39a9, the commit Chromium 152.0.7977.167 pins; Electron's one patch to it, link_with_loader_path.patch; and the build settings in that tree (BUILD.gn, ffmpeg_generated.gni, chromium/config/Chrome/mac/arm64/) with Electron's release.gn. |
Ask for the source
For at least 3 years after IronLabs Tech last distributes a version of Auralyn that contains these libraries, we will give anyone who asks a complete machine-readable copy of their source, for no more than the cost of physically making and sending the copy.
Email support@ironlabstech.com and name the Auralyn version. You do not need to be a customer.
Using a changed copy
The LGPL lets you change these libraries and use your changed copy with Auralyn. Auralyn loads libffmpeg.dylib as a separate file and starts the helper as separate programs, so either can be replaced. The app then needs to be signed again.
Other open-source parts
Auralyn also uses Electron and Chromium, the Oxanium typeface and a number of smaller open-source packages, under licences such as MIT, BSD and the SIL Open Font License. Every one of them, with its full licence text, is listed in Auralyn under Help → Third-Party Notices.
Something missing or wrong on this page? Email support@ironlabstech.com.