What is anivis?

AniVis is a single HTML file that turns a background image and a song into a music visualizer video, entirely inside a web browser. There is nothing to install, no account to create, and no files get uploaded anywhere, since all the processing happens locally on the user's own computer. The tool reads audio in real time using the browser's Web Audio API, drives a visualizer drawn on an HTML canvas that reacts to the beat, and can record the result as a video file using the browser's built in recording API. Five visualizer styles are available, including a full circular ring, an arc shaped crown, a waveform line, and two styles of animated bars, and any of them can be combined. Colors can be a gradient, a solid color, or an automatically cycling rainbow. Every visual element can be dragged directly in the live preview to reposition it, and sliders control size, sensitivity to the music, glow, and background darkness. Recording works two ways. The simplest is the built in recorder, which captures up to 4K resolution at 60 frames per second and saves a WebM file that can be uploaded to YouTube without any conversion. For more reliable high resolution results, the README also documents a workflow using OBS Studio to screen record the browser window, along with a keyboard shortcut that hides all the interface elements so the recording shows only the visualizer itself. Because the entire application is one HTML file with no external dependencies, anyone can download it, open it directly in a browser, and modify or restyle it freely. The project works best in Chrome or Edge, since Firefox has limited support for the video format used during recording. It is released under the MIT license.