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About this tool
Export selected video frames as a single tiled sprite sheet PNG.
The Video Frame to Sprite Extractor samples frames from a local video at one frame every 1, 2 or 5 seconds, scales each to 240 pixels wide, and tiles the first 25 of them into a single 5x5 PNG sprite sheet. It runs FFmpeg compiled to WebAssembly inside your browser, so the video is decoded on your own machine and only the finished PNG is downloaded. It suits anyone who needs a contact sheet of a clip — video preview scrubbers, storyboards, QA passes, thumbnail picking — in one file rather than 25 loose images.
Open Video Frame-to-Sprite Extractor on AltFTool — it loads instantly in your browser.
Choose your clip with Source file — the picker accepts any video/* file, and it is written to an in-page FFmpeg filesystem rather than uploaded.
Set Sampling to 1 frame/second, 1 frame/2 seconds or 1 frame/5 seconds, then press Process locally.
FFmpeg WebAssembly scales each frame to 240px wide, tiles the first 25 into a 5x5 sheet and downloads altftool-video-frame-to-sprite-extractor.png.
The 5x5 tile filter assembles the sampled frames into a single sprite sheet, so there is nothing to zip, rename or re-order afterwards.
One frame per second suits a short clip; one per five seconds spreads the same 25 tiles across just over two minutes of footage.
FFmpeg runs as WebAssembly in the page, so even long or confidential recordings are never sent to a server for frame extraction.
25 — a fixed 5x5 grid. The extractor takes the first 25 sampled frames at your chosen rate and writes them as one PNG, so a 1-frame-per-second setting covers the first 25 seconds and a 1-frame-per-5-seconds setting covers the first 125 seconds.
Each frame is scaled to 240 pixels wide with the height calculated to preserve the source aspect ratio, so a 16:9 clip produces 240x135 tiles and a 5x5 sheet about 1200x675 pixels.
No. The file is written into an in-browser FFmpeg WebAssembly filesystem, processed locally, and read back as a PNG blob. The FFmpeg core itself is fetched once from a public CDN, but your media is not transmitted.
Anything the in-browser FFmpeg build can decode, which covers the usual MP4, WebM, MOV and MKV containers with common codecs. Very large or long files take proportionally longer because decoding happens on your CPU rather than on a server.