Video compressor
Choose a video, pick a frame size and a bitrate, and record a lighter copy. The tool shows an estimate before and the real size after. If the new file is not smaller than the original, it tells you instead of giving you a bigger file.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Choose a video file. Its size and length are shown.
- Pick a Frame size (percentage of the original) and a Video bitrate. The bitrate is filled in with a starting value for the chosen size.
- Check the expected size, then press Compress video.
- If the new file is smaller you can preview and download it; the saving is shown as a percentage.
How it works
The clip is played into a canvas of the reduced size and recorded with MediaRecorder at the bitrate you set. The file size is roughly (video bitrate + 96 kbit/s for sound) × seconds ÷ 8, and the real size is measured after recording and compared with the original.
Worked example
A 60 s clip at 1000 kbit/s with sound is about (1,000,000 + 96,000) × 60 ÷ 8 = 8.2 MB.
Tips
- Halving the frame size cuts the pixel count to a quarter, which matters more than a small bitrate change.
- Lower bitrates look blocky in fast motion; try the next step up if the result is too rough.
Frequently asked questions
How does the tool make a video smaller?
It records the clip again at a smaller frame size and at the video bitrate you set, with the sound at 96 kbit/s. File size is about bitrate times length divided by 8, which is what the estimate shows.
Why does it sometimes say the original is smaller?
If the source is already compressed more than your settings allow, re-recording can give a bigger file. The tool compares the sizes and only offers a download when the new file is smaller.
Why does it take as long as the video?
The browser has no built-in way to convert a video file, so the tool plays the clip into a canvas and records the canvas with MediaRecorder. That happens at playing speed: a 1-minute clip takes about a minute (half that at 2x speed). Keep the tab open and visible, because browsers slow down background tabs.
Which file format do I get?
WebM in Chrome, Edge and Firefox, which can be played by those browsers and most players. Safari records MP4 instead. The original format is not kept, because the clip is recorded again from the picture the browser shows.