Licences and third-party notices

Last updated 15 October 2026.

Tessera is proprietary software. It is built on components that are not, and several of their licences require that this page exists. The complete licence texts are installed alongside the application; this page is the public copy.

Tessera

© 2026 Studio Heino. All rights reserved. Your rights to use it are set out in the Terms of Use.

Qt

Tessera is built with the Qt toolkit, version 6.11.1, which it uses under the GNU Lesser General Public License version 3. Qt is a trademark of The Qt Company Ltd.

In accordance with the LGPL:

• the full texts of the LGPL v3 and of the GNU GPL v3 it supplements are included with the installed application, in licenses/Qt, together with Qt's own list of the third-party components inside it;
• the Qt libraries are linked dynamically and shipped as separate files beside the application, so you may replace them with your own build of Qt 6.11, modified or not, and the Terms of Use do not restrict that;
• the source of Qt 6.11.1 is published by the Qt Project at download.qt.io. You may also obtain it, and the object files needed to relink Tessera against a modified Qt, by writing to hello@studioheino.com, for at least three years after we last distribute that version.

Qt modules used under the LGPL: Qt Core, Qt GUI, Qt OpenGL, Qt Network, Qt QML, Qt Quick, Qt Quick Controls, Qt Quick Dialogs, Qt Multimedia, Qt SVG, Qt WebSockets, Qt Positioning, Qt Serial Port, Qt Shader Tools, Qt WebChannel and Qt WebEngine. Qt WebEngine contains Chromium, whose components keep their own licences. Qt Quick 3D, and Qt Quick Timeline which it requires, are not available under the LGPL: only under the GPL v3 or a commercial licence from The Qt Company. Resolve that before this page goes live (a commercial licence for those modules, or a release without 3D), then name them here with the licence they are actually used under.

FFmpeg

Video and audio are decoded and encoded with libraries from the FFmpeg project, version 7.1.5, used under the GNU Lesser General Public License version 2.1 or later. They are unmodified FFmpeg, built for Tessera with royalty-free codecs only, linked dynamically and shipped as separate library files beside the application, which is what permits their use in a proprietary application under that licence.

In accordance with the LGPL:

• the full text of the LGPL v2.1 is included with the installed application, in its licenses folder (Settings → About → Open source licences opens it);
• the complete corresponding source code of the FFmpeg that ships — with the exact configuration and the scripts that build it — is included with every installation, in licenses/source. You can also ask for it at hello@studioheino.com;
• you may modify those libraries, or replace them with your own build of FFmpeg 7.1, and the Terms of Use do not restrict that (section 4). Because they are separate dynamic libraries, replacing the files is all that relinking requires.

Built into those libraries, each under its own licence (full texts in the same folder):

FFmpeg is a trademark of Fabrice Bellard, originator of the FFmpeg project.

Media format patents

Some media formats are covered by patents that are licensed separately from the software that implements them. A licence to the software is not a licence to the patents.

Tessera contains decoders and encoders only for formats that are royalty-free or whose patents have expired. It contains no implementation of H.264/AVC, H.265/HEVC, VVC, VC-1, AAC or E-AC-3. When you add a video or sound in one of those formats, Tessera asks your operating system's own decoder to read it — on Windows, Media Foundation — and converts it to AV1 video and Opus audio. That decoder is supplied and licensed with your operating system, or with a codec you installed; if there is none, the file is kept as it is and Tessera says it cannot play it. No licence under any patent is granted, as stated in section 9 of the Terms of Use.

The collaboration server

The reference tessera/1 server is a separate program. It is written in Go and uses:

The collaboration server itself is proprietary. Running it on your own hardware is a commercial licence agreed with us rather than a right granted by an open-source licence; the third-party components listed above keep their own licences inside it, and any of them that require it are honoured in the same way as in the application.

The tessera/1 protocol specification is a separate document and is published openly, so a server that speaks it can be written by somebody else without asking us — that is what the conformance check is for. Name the exact licence document and its version here, and link it, before this page goes live. "Proprietary" is a category, not a licence — a reader about to deploy needs the terms they will be bound by.

This website

The site is a Go program using only the standard library. It serves no third-party code and embeds no third-party assets. The icons are drawn in the page rather than imported from an icon set.

Trademarks

Windows, PowerShell and SmartScreen are trademarks of Microsoft Corporation. Docker is a trademark of Docker, Inc. Cloudflare is a trademark of Cloudflare, Inc. Their use here is descriptive and implies no affiliation or endorsement.