Recorder 3X is based on OBS Studio which is a open source software under license GPLv2.  Get Our Source Code.
Introduction to features：
High performance real time video/audio capturing and mixing. Create scenes made up of multiple sources including window captures, images, text, browser windows, webcams, capture cards and more.
Set up an unlimited number of scenes you can switch between seamlessly via custom transitions.
Intuitive audio mixer with per-source filters such as noise gate, noise suppression, and gain. Take full control with VST plugin support.
Powerful and easy to use configuration options. Add new Sources, duplicate existing ones, and adjust their properties effortlessly.
Streamlined Settings panel gives you access to a wide array of configuration options to tweak every aspect of your broadcast or recording.
Modular 'Dock' UI allows you to rearrange the layout exactly as you like. You can even pop out each individual Dock to its own window.