About Video Compressor
Video Compressor shrinks MP4, MOV and WebM files using H.264 at a quality you choose — typically cutting size by 50–80% for screen recordings and phone videos. The whole pipeline runs in your browser through ffmpeg.wasm, a WebAssembly port of FFmpeg, so the file is never uploaded. Pick a target quality (CRF), optionally cap the resolution, and the tool re-encodes locally. Processing speed depends entirely on your device's CPU — a five-minute clip takes roughly the same time on a laptop as it would in desktop FFmpeg.
- No uploads
- Browser-only
- Works offline
- 100% free
How it works
- 1
Drop a video
MP4, MOV or WebM. The tool reads the duration, codec and dimensions and shows them before you start.
- 2
Pick quality and size
Choose a quality preset (CRF 18 looks visually lossless, 23 is YouTube-grade, 28 saves the most space) and an optional max height — 720p, 1080p or original.
- 3
Re-encode and download
ffmpeg.wasm runs the H.264 encode locally. A progress bar shows current frame; the output downloads as soon as encoding finishes.
Related tools
Browse allCut a clip from any video in your browser. Fast stream-copy by default, frame-accurate re-encode if you need it.
Convert a video clip to an animated GIF with two-pass palette extraction. Custom FPS + height. ffmpeg.wasm.
Pull the audio track out of any video as MP3, WAV, AAC, or OGG. Configurable bitrate. ffmpeg.wasm in your browser.
Shrink JPEG, PNG, and WebP without visible quality loss.
Frequently asked questions
Are my files uploaded to a server?
No. Every tool on SnapToolz runs entirely inside your browser using JavaScript and WebAssembly. Your file is read locally, processed in memory, and the result is offered as a download. Nothing is sent to a server — there isn't one to send to.
Why is the encode slow compared to desktop FFmpeg?
ffmpeg.wasm runs single-threaded inside a WebAssembly sandbox and can't use hardware H.264 encoders (NVENC, VideoToolbox, QuickSync). For a 10-minute 1080p clip expect several minutes on a modern laptop; on phones it's slower still. Lower the resolution or pick a faster preset if it's taking too long.
What's the maximum file size?
ffmpeg.wasm has a working memory limit of around 2 GB on most browsers. Files up to roughly 1.5 GB input typically work; beyond that you'll see out-of-memory errors. Long 4K clips are the most likely to hit this — trim them first with Video Trimmer.
Does it re-encode audio too?
By default audio is copied through unchanged when possible, preserving bitrate and quality. If the source audio is in a codec the output container doesn't support, it's transcoded to AAC at 128 kbps.
Does it work offline?
Yes. SnapToolz is a Progressive Web App. After your first visit, the app is cached on your device and every tool keeps working without an internet connection.
Is SnapToolz free?
Yes — every tool is 100% free with no sign-up, no watermark, no hidden tier. The whole platform is open source and we have no plan to gate features.