Third-party licenses
Last updated: 4 October 2026
Soundtropic is built with free software. Almost all of it uses permissive licenses (MIT, BSD, Apache or ISC), whose notices travel inside the files themselves. Here are the pieces your browser downloads whose licenses ask for a separate notice, with the license text and where to get their source code.
LAME 3.100
- License:
- GNU LGPL, version 2 or later
- What for:
- Creates the MP3 files in the audio converter (Tools → Converter and clips).
- How it ships:
- It ships as a separate, unmodified module (@mediabunny/mp3-encoder 1.56.1) that your browser only downloads when you convert to MP3 and that runs in its own process (Worker). You can replace it with another compatible version of LAME: our code only hands it the audio and collects the MP3.
- Credit:
- MP3 encoding by LAME — https://lame.sourceforge.io
FFmpeg (AAC)
- License:
- GNU LGPL, version 2.1 or later
- What for:
- Only if your browser has no AAC encoder of its own: it makes the sound of the videos you export in the studio with “Export here”.
- How it ships:
- A separate, unmodified module (@mediabunny/aac-encoder 1.56.1) that is only downloaded in that case and runs in its own Worker.
Mediabunny 1.56.1
- License:
- Mozilla Public License 2.0
- What for:
- Reads and writes audio and video files in your browser: converter, tags, album downloads and the studio. Unmodified.
Spleeter 4stems
- License:
- MIT · Deezer Research
- What for:
- The networks that split vocals, drums, bass and the rest (Tools → Split stems).
spleeter-4stems-onnx
- License:
- Apache 2.0 · Best-Practice
- What for:
- The same networks, exported to ONNX so they run in the browser. Unmodified.
ONNX Runtime Web 1.30.0
- License:
- MIT · Microsoft
- What for:
- The engine that runs those networks in your browser (the splitter's and the video studio's).
U²-Netp
- License:
- Apache 2.0 · Qin et al.
- What for:
- The network that finds the person in a photo, to remove the background and to fit the framing (video studio → AI). Unmodified.
Real-ESRGAN general x4v3
- License:
- BSD 3-Clause · Xintao Wang et al.
- What for:
- The network that enlarges a small photo, inventing the missing detail (video studio → AI → Improve a photo). The official weights, exported to ONNX unmodified.
- Credit:
- Copyright (c) 2021, Xintao Wang. All rights reserved.
Tipografías
- License:
- SIL Open Font License 1.1
- What for:
- Montserrat, Inter, Noto Kufi Arabic and Noto Sans Arabic on the website; Anton, Bebas Neue, Cormorant Garamond, Montserrat, Noto Kufi Arabic, Oswald, Pacifico and Pinyon Script in the studio videos.
For at least three years, if you want the complete source code of the LGPL-licensed pieces on a physical medium, write to us at hola@naysof.es and we will send it for no more than the cost of shipping.