The default configuration uses only permissively-licensed components (BSD / MIT). An optional high-quality video component (FFmpeg native libraries) is an LGPL build, used via dynamic linking and user-replaceable; it contains no GPL code and no patent-pool encoders (video encoding is VP8/VP9 via libvpx, which is royalty-free).
Components
| Component | License | Copyright / project |
|---|---|---|
| SIPSorcery | BSD-3-Clause | © 2010–2026 Aaron Clauson, Christophe Irles, Rafael Soares & Contributors — github |
| SIPSorceryMedia.Encoders (incl. libvpx / VP8/VP9) | BSD-3-Clause | © Aaron Clauson & Contributors; libvpx © The WebM Project authors — github |
| SIPSorceryMedia.Abstractions | BSD-3-Clause | © Aaron Clauson & Contributors |
| SIPSorceryMedia.FFmpeg (managed wrapper) | LGPL-2.1-only | © Aaron Clauson & Contributors — github (dynamic linking; source at URL) |
| FFmpeg.AutoGen (managed bindings) | MIT | © 2025 Ruslan Balanukhin — github |
| FFmpeg (native libraries, optional) | LGPL-2.1-or-later | © the FFmpeg developers — ffmpeg.org. LGPL "shared" build: no --enable-gpl, no libx264/libx265. Modified (one file, see below). See the source offer below. |
| libvpx | BSD | © The WebM Project authors — webmproject.org |
| Vortice.Windows (Direct3D 11 / DXGI interop) | MIT | © Amer Koleci and Contributors — github |
License summaries
BSD-3-Clause and MIT are permissive licenses that allow use in proprietary software provided the copyright notice and permission text are retained; the software is provided "as is" without warranty. Full texts: BSD-3-Clause, MIT.
LGPL-2.1 (SIPSorceryMedia.FFmpeg wrapper and the optional FFmpeg native libraries) permits use in proprietary software via dynamic linking, provided users can replace the LGPL component and can obtain its source. Full text: GNU LGPL v2.1.
FFmpeg — LGPL notice and written offer for source
The optional FFmpeg native libraries (in the application's ffmpeg\ folder) are licensed under the GNU LGPL v2.1 or later. They are dynamically linked and packaged as separate, user-replaceable files — you may replace them with your own compatible LGPL FFmpeg build (8.x shared, x64). The full license text ships beside the binaries (ffmpeg\ffmpeg-COPYRIGHT.txt).
Modifications: since version 3.6.0 this build is FFmpeg as released plus one change of ours to libavcodec/libvpxenc.c, dated 2026-10-14: a runtime-rate option that applies a new bitrate and keyframe cap to a running VP8 encoder instead of restarting it. The change is licensed under the LGPL v2.1 or later, as FFmpeg is. It ships with the application as ffmpeg\patches\0100-libvpxenc-runtime-rate.patch, is included with the source below, and ffmpeg\BUILD-INFO.txt names it. A replacement FFmpeg build without it is fully supported: the application detects that the option is missing and restarts the encoder for each bitrate change instead.
Written offer for source: the complete corresponding source for this exact FFmpeg build (the pinned release archive and the build scripts/configuration used to produce it) is available to any recipient of this product, free of charge, for at least three years from distribution. See ffmpeg\BUILD-INFO.txt in the installation folder for the exact version and provenance, and contact us to obtain the source archive. This build contains no GPL components and no patent-pool encoders; video encoding is VP8/VP9 via libvpx (royalty-free). FFmpeg is a trademark of Fabrice Bellard, originator of the FFmpeg project.
Full notices
The complete third-party notices also ship with the application (the THIRD-PARTY-NOTICES.txt file in the installation folder, and ffmpeg\ffmpeg-COPYRIGHT.txt when the FFmpeg component is present). Questions? Contact [email protected].