Question 1

Which video formats can I compress online without uploading?

Accepted Answer

MP4, MOV, MKV, WebM and other mainstream video containers.

Question 2

How do I compress MP4 to a smaller file size in the browser?

Accepted Answer

Basic mode targets a file size; Advanced mode lets you tune quality (CRF), codec (H.264/H.265), and encode speed to balance size and clarity.

Question 3

Does compressing video reduce quality when I shrink the file?

Accepted Answer

Smaller files usually mean re-encoding. Quality depends on your target size or quality settings — test a short clip first, then process the full video.

Free Local Video Compressor