Video Compressor
Compress video in your browser
Compress video in your browser Runs locally in your browser
About the
The Video Compressor shrinks video files directly in your browser using ffmpeg compiled to WebAssembly. No file ever leaves your device, which matters when the video is client work or personal footage you would rather not upload to a stranger's server.
Three compression modes cover the common cases: quality mode uses CRF encoding so you pick a visual quality and let the encoder find the smallest file; bitrate mode pins the output to a number you choose, which is what you need when a platform caps uploads at a fixed size; target-size mode works backwards from a megabyte budget and calculates the bitrate from your video's real duration.
The engine is the same ffmpeg that professionals use on the command line, running H.264 encoding locally. A typical 100 MB phone video compresses to 10-20 MB in about a minute on a desktop, with no watermark and no sign-up.
Where people use the
- Shrinking a phone video before emailing it or attaching it to a ticket.
- Meeting a platform's upload size cap without visible quality loss.
- Making a portfolio or client review copy that loads fast.
- Freeing storage on a camera roll before a trip.
How to use the
- 1
Drop in your video
Select or drag an MP4, MOV, WebM or MKV file. The tool reads the duration from the video itself, which the target-size mode needs.
- 2
Pick a mode
Quality mode: drag the CRF slider (lower is better). Bitrate mode: choose a Mbps value. Target-size mode: enter the megabyte budget.
- 3
Compress
Click Compress. The progress bar tracks the real encode progress. Stay on the tab; the first run downloads the ffmpeg engine, which takes a few seconds.
- 4
Download
Compare the before/after sizes, preview the result inline, and download the MP4. Nothing was uploaded at any point.
Tips and best practices
- Start with CRF 28 and only go lower if the preview looks soft.
- Target-size mode needs the real duration; wait for the video to finish loading before compressing.
- For screen recordings, CRF 30 or higher usually still looks clean.
Frequently asked questions
Is there a file size limit?
The practical limit is your device's memory, not a server quota. Videos up to about 500 MB work comfortably on a desktop; phones handle smaller files better. There is no artificial cap and nothing is uploaded.
Why is the first compression slow?
The first run downloads the ffmpeg WebAssembly engine (about 25 MB) from a CDN. After that it is cached and later compressions start in about a second.
Does compression lose quality?
Always some, by design. CRF 23-28 is the usual sweet spot: visually near-identical at a fraction of the size. Target-size mode pushes harder, so check the preview before downloading.
Can I compress for a specific platform?
Yes. Bitrate mode with 8 Mbps suits most HD uploads; target-size mode is for hard caps like email attachments or form uploads.
Does it work on mobile?
It runs in mobile browsers, but large videos can exhaust phone memory. For files over roughly 100 MB, a desktop is strongly recommended.