Blur a Video Online: A Part, the Background or All of It

Tested on 2026-10-07 in Chrome with our own AI clips and test files; not tested in Safari or Firefox. Twenty-two exports were made through this page, five of them on a production build. Ten seconds of a 768 × 1344 clip with two boxes at 720 × 1260 and 30 frames per second took 31 seconds (6.7 MB); 6 seconds of a 1280 × 720 clip made into 720 × 1280 with a blurred background took 10 seconds (2.7 MB); 5 seconds blurred whole at 1920 × 1080 took 13 seconds (1.7 MB); the two 5-second examples on this page took about 7 seconds each (1.3 MB each). The limits were run at both ends: 60 seconds at 720 × 1280 and 30 frames per second (1,800 frames) took 2 minutes 15 seconds (40.6 MB), a 0.1-second part gave 3 frames, and 60.5 seconds was refused before anything was made. An MP4, a MOV and a WebM file were each run. ffmpeg read every result as H.264 with AAC sound (48 kHz stereo) of the stated length; the clip without a sound track gave a silent MP4 and the page said so. Result frames were compared with the source at the same moments: inside blurred boxes the fine detail fell to between a tenth and a quarter of the original (to a third inside a pixelated box, whose block edges count as detail), the part of the frame outside the boxes differed by under 2 of 255 brightness levels on average, and a box timed to end at second 5 was sharp again at second 7. On the production build the browser sent no network request between choosing a file and downloading the result. The readability figures in the FAQ come from a 1280 × 720 test clip with lines of 24, 36, 48, 72 and 110 pixel letters, read by us from the exported frames. The MP4 container writer is our own code; sound is written with the browser's AAC encoder.

Updated Oct 7, 2026 · How we test