Openshot/openshot-qt — reverse-engineered prompt

Build me a free open source desktop video editor for Windows, Mac, and Linux, similar to OpenShot.

I want users to be able to import videos, audio, and images, arrange them on an advanced timeline with unlimited tracks, drag clips around, trim, cut, resize, rotate, snap, zoom, and preview changes smoothly. It should support transitions, overlays, watermarks, titles, subtitles, scrolling credits, image sequences, slow motion, fast motion, reverse playback, frame by frame stepping, and basic audio mixing.

Please include common video effects like brightness, gamma, hue, greyscale, and chroma key. It should use FFmpeg or a similar backend so people can open and export many popular formats and render final videos in common codecs.

Make the interface friendly and visual, with drag and drop support. Use Python with a Qt style desktop UI if that makes sense. Set it up so I can run it locally from source, and look up current docs online if you need to.