Telvi - Open source components

Version: 1.0 Last changed: 16 August 2026 Covers: Telvi Server, Telvi Player, Telvi Importer

Translation This is a translation of the Dutch text. Where the two differ in interpretation, the Dutch version prevails.

Telvi is built on the work of a great many others. This page lists the open source components we use, under which licence, and what that means for you.

1Why this page exists

Open source licences give us the right to use other people's work, but attach conditions. The main ones are: credit the authors, make the licence text and source code available, and for some licences give you the ability to replace the component. This page meets those obligations and tells you where you stand.

The licences of these components take precedence over our own terms and conditions as far as those components are concerned. If our terms contain a restriction that an open source licence expressly permits, the open source licence applies.

2Important: the LGPL components

Part of Telvi relies on components under the GNU Lesser General Public License (LGPL). This mainly concerns media playback: video and audio are played by VLC.

The LGPL gives you the right to replace those components with your own version. In practice that means the following.

The LGPL components are shipped as separate files, not baked into our software. So you can replace them with your own build of the same library.
The source code of those components is publicly available from the original authors. References are in the table below.
If you want to receive the source code of an LGPL component from us, or need information to relink Telvi against your own version, send a message to info@eventalmedia.com. We supply it free of charge, or at no more than the cost of distribution.

What this does not mean The LGPL gives you rights to those specific components. Telvi itself is not open source and remains the property of Evental Media; our own terms apply to it.

3Overview of components used

The table below reflects the components currently in Telvi. Versions change with updates; licences usually do not.

Media playback

Component	Licence	What we use it for
VLC / libVLC VideoLAN	LGPL 2.1 or later	The actual playback of video and audio in Telvi Player. videolan.org
LibVLCSharp VideoLAN	LGPL 2.1 or later	The bridge between Telvi and libVLC.
FFmpeg libavcodec, libavformat, libavutil, libswscale	LGPL 2.1 or later	Decoding video and audio formats, and reading properties of media files. Shipped as part of VLC and built without GPL components. ffmpeg.org
NAudio	MIT	Audio processing, including loudness measurement.

Graphics and display

Component	Licence	What we use it for
Vortice.Windows	MIT	Driving the graphics card for image output.
AForge.NET	LGPL 3 / GPL 3 per component	Image processing and access to video sources.
Microsoft Edge WebView2	Microsoft licence not open source	Displaying websites as part of a broadcast.

Server, storage and interface

Component	Licence	What we use it for
.NET and ASP.NET Core Microsoft	MIT	The platform Telvi runs on.
SQLite	Public domain	The index of your media library.
Microsoft.Data.Sqlite	MIT	The bridge to SQLite.
Bootstrap	MIT	Parts of the styling of the web interface.
Monaco Editor Microsoft	MIT	The code editor in the scripting library.
Swashbuckle	MIT	Documentation of the programming interface (API).

4GPL components among the VLC plugins

VLC ships with a large collection of plugins. The vast majority are LGPL, but a couple are under the stricter GPL. For completeness, here is which ones.

Plugin	Licence	What for
x264 libx26410b_plugin	GPL 2 or later	Encoding H.264 video. Telvi does not use this: Telvi plays out, it does not encode.
VLC Lua liblua_plugin	GPL 2 or later	VLC's own scripting facility. Telvi does not use it; the scripting library inside Telvi is entirely separate.

Telvi does not call these two plugins; they are included because they are part of VLC's standard plugin set. The terms of the GPL apply to those components, including your right to the source code. See chapter 5.

5Full licence texts

If you would like to see the full licence text of a component, we will send it to you free of charge. Email info@eventalmedia.com stating which component. The licence texts are also publicly available from the original projects.

The same applies to the source code of the LGPL and GPL components listed above: we make it available on request, free of charge or at no more than the cost of distribution. This offer is valid for anyone who has received a copy of Telvi, and remains open for at least three years after delivery.

6Something missing or wrong?

We do our best to keep this list complete and correct. If you spot a component that is missing, or a licence that is wrong, let us know at info@eventalmedia.com. We will fix it.

7With thanks to

Without VideoLAN, the FFmpeg project and the many other authors above, Telvi would not exist, or at least not at this price. Our thanks for that.