pizzalater/spritekit

SpriteKit is a browser-based tool that converts a short MP4 video into a transparent PNG sprite sheet. It was built specifically to solve the gap between AI video generators (which output MP4 files) and game engines (which need sprite sheets). You open the HTML file directly in any browser, no installation required. The workflow moves through four steps. First you load an MP4 clip, ideally one where the character is filmed against a solid color background like green or magenta. Second, you remove the background using a color picker: click the eyedropper, sample the background color from the video frame, then adjust the tolerance slider to control how aggressively similar colors get removed. A matte view shows the transparency channel in black and white so you can spot problem edges. Third, you scrub through the video and mark which specific frames you want included in the sprite sheet. You can preview the selected frames playing back as an animation. Fourth, you set the grid size (columns and rows) and cell dimensions, generate the sheet, and download it as a transparent PNG. An optional JSON file can be downloaded alongside it containing the coordinates of each cell, for use in a game engine loader. The README is explicit about what the tool does not do: it does not fix inconsistent or wobbly frames from AI video generators, and it does not redraw anything as true pixel art. It arranges whatever the video contains and removes the background color. The tool runs entirely in the browser and never uploads anything. It is built with plain HTML, CSS, and vanilla JavaScript with no external dependencies or frameworks. The license is MIT.