This plugin for OBS Studio
enables a streamer to display Qt Quick
content as an overlay on their stream.
Owing to the fact that Qt Quick files are able to import installed component functionality, the versatility and flexibility of this cannot be overstated.
As an example, I've used this plugin to display realtime data from my solar charge controller including a graph displaying power generation and power consumption during an "EcoStream", as well as interfaced it via WebSocket to an electronic drum kit interface to display drum pad activations in the form of a fancy graphical effect on a mockup drumkit image overlayed unobtrusively on the stream.
The control options available to an experienced Qt Quick developer with this plugin makes the standard scene and transition mechanisms of OBS Studio seem primitive. The Qt Quick overlay has access to QtMultimedia, allowing access to cam or capture devices alike. From here, scenes can be implemented with effects, transformations, QtQuick3D, an animations.
On a simpler level, the only included example simply renders a WebEngineView with an implicitly transparent background. This allows a streamer to utilise one of the many dynamic overlays implemented in HTML5 which (at the time of release) were only usable on Windows platforms where the webview plugin was available.
Though not updated to match the latest release of OBS Studio due to retiring from streaming, the source can be found at https://github.com/danieloneill/obs-qmlview