Choose a file, check compatibility and create a real downloadable output on your device. No account or file upload is needed.
Fast cuts may begin at a nearby keyframe and can fail when source codecs do not fit MP4. Accurate cuts re-encode the first video and optional first audio stream; other tracks are omitted.
Single-thread FFmpeg WASM runs in a worker. The engine is about 32 MB; long or high-resolution videos may exceed browser memory. Input codecs are checked during processing. MP4/MOV/MKV use H.264/AAC; WebM uses VP8/Opus; AVI uses MPEG4/MP3; FLV uses FLV1/MP3; WMV uses WMV2/WMA2; MPEG uses MPEG2/MP2. GIF has no audio. Some outputs need a desktop player. Compression may increase size.
Use a recent desktop browser with WebAssembly, workers, Blob downloads and enough free RAM. File contents stay in this tab; engine/model download requests do not include your files. Browser extensions can have their own access. This tool uses the single-thread engine and does not require cross-origin isolation; a future multithread engine would require COOP/COEP headers and SharedArrayBuffer. Cancel terminates active workers. Clear releases local file references and output URLs.
See the full compatibility matrix and engine licenses →