Donaldson R F Compress Video
Make a video file smaller. Pick a quality preset, or ask for a target size in megabytes, and see exactly how much smaller it became. The tool never hands you back a file bigger than the original, and nothing is uploaded.
How it works
The video is encoded again as H.264 video with AAC sound in an MP4 file, using a quality setting that keeps the picture looking good while throwing away detail the eye hardly notices. The result is usually a third to a tenth of the size of a phone or camera video. The tool shows the size before and after, and the percentage saved.
The work is done by ffmpeg compiled to WebAssembly. That engine is about 31 MB. It is downloaded only when you press Compress video, checked against a known fingerprint, and stored in your browser, so the next time it starts at once. It runs in the background, so the page stays responsive, and you can press Cancel at any time.
Presets, size and target size
Smallest file gives the biggest saving and a visibly softer picture; Balanced is the right choice for most videos; Best quality keeps almost all the detail. Choosing a smaller picture size saves a lot more, and also makes the job faster.
With target size the tool works out the video bitrate from the length of the video and encodes to that. The result is close to the target but never exact: the size can be off by ten per cent or more, especially for very short or very busy videos. When the estimated time is short enough, the tool uses two passes (it analyses the video first, then encodes it), which spreads the quality more evenly over the video; for longer jobs it uses one pass and says so. In our tests both landed within about seven per cent of the target, slightly under it. If the target is very small for the length of the video, the picture will look poor, and the page warns you.
How long does it take?
Encoding in a browser uses one processor thread, so it is much slower than a desktop program: roughly half of real time for 720p video and a quarter of real time for 1080p. The page shows an estimate before you start and warns you when it is more than about five minutes; a smaller picture size, or a shorter part of the video (see Trim & Cut Video), is the way to make it faster.
Will the file always get smaller?
Not always. A video that is already highly compressed can come out larger when it is encoded again. If that happens the tool tells you and gives you your original back instead of the bigger file. Try a smaller picture size or the Smallest file preset in that case.
Frequently asked questions
Is my video uploaded?
No. The only download is the conversion engine itself. Your video is opened directly from your disk and never sent anywhere.
What about videos with several audio tracks?
Only the first audio track is kept. Use Video Converter to keep all tracks, or Mute Video to remove the sound.
Will it work with protected videos?
No. Videos protected by copy protection (DRM), such as many downloaded films or streaming-service files, cannot be read. Only use videos you have the right to use.
Related tools: Video Converter, Trim & Cut Video, Mute Video.