Compress video files directly in your browser using FFmpeg compiled to WebAssembly — no server uploads required. Supports MP4, WebM, Ogg, QuickTime (MOV), and AVI formats. Choose between mild, medium, or harsh compression strength, and pick your priority: speed (ultrafast encoding), balanced, or maximum file size reduction (slow encoding). The tool re-encodes video with H.264 and audio with AAC at 128kbps. Harsh compression also downscales to 720p, while medium caps at 1080p. See a thumbnail preview, original and compressed file sizes, and percentage saved. Note: very large videos will put your device under heavy load since all processing happens locally.
TonniTools is built to run locally in your browser. Since no data ever leaves your device, everything works, even without internet.