Shrink a video without wrecking the quality

Almost everything about video file size comes down to three numbers. Learn what each one costs you and you can shrink a file by 90% while still producing something people are happy to watch.

1. Resolution — change this first

Resolution is width × height in pixels, and it is the setting with the biggest visual impact. Halving both dimensions cuts the pixel count to a quarter. Halving only one cuts it in half.

The important insight is that resolution should match the screen it will be watched on, not the screen it was filmed on. A 4K phone clip destined for a messaging app is being shown on a device roughly 1080 px wide at most, and usually smaller. Downscaling it to 720p removes data that the display literally could not have shown you anyway.

2. Bitrate — give it enough, not more

Bitrate is how much data per second is spent describing the picture, usually measured in Mbps. Too low and you get visible blocks and smearing; too high and you are storing detail nobody will see.

A workable rule of thumb for H.264:

480p — 1 to 1.5 Mbps
720p — 1.5 to 2.5 Mbps
1080p — 3 to 6 Mbps

Fast motion, confetti, water and heavy film grain all need more. A talking head or a static product shot needs less.

3. Frame rate — the setting everyone forgets

30 fps and 60 fps describe how many frames per second are stored. 60 fps is roughly twice the data for the same duration. For sports, gameplay and fast action it is worth it. For interviews, product demonstrations or scenery, 30 fps is indistinguishable and halves your file size.

If a clip was shot at 60 fps and is going to be viewed once in a group chat, dropping to 30 fps is the single largest saving available after resolution, and almost nobody will notice.

The order to change them in

Drop the frame rate to 30 if the content is not fast-moving. Free saving, no visible cost.
Cap the resolution at what the target screen can actually show — usually 720p for phones.
Set the bitrate using the table above. Only go lower if the file is still too big.
Strip the audio if the video will autoplay muted on a web page. Audio is 128 kbps of pure overhead in that case.

What not to do

The mistake almost everyone makes is attacking quality first — leaving the resolution high and crushing the bitrate. That produces the worst possible result: a file that still takes up space and looks actively bad, with blocky artefacts and smeared movement. Lower the resolution first; the eye is far more tolerant of a smaller, clean image than of a large, broken one.

To try it, use the video compressor. Pick a resolution cap and a compression level and it works out the bitrate for you. Encoding happens on your own device, so nothing is uploaded and there is no file-size ceiling imposed by a server.