This is a small HTML5 Single-Page-Application (SPA), running inside a Browser or directly inside a Source Dock of OBS Studio, for interactively controlling the position and/or size of one or more related Crop/Pad source filters in OBS Studio through a remote OBS WebSockets connection. The transition from the old to the new crop position and/or size is performed over a configured time duration and with a cubic in/out easing, in order to somewhat simulate the behaviour of a PTZ camera.