Compress video (H.264)

Compress MP4, MOV, MKV and WebM videos offline on your Mac — three quality levels, per-file savings, batch over a dropped folder.

Compress videos offline in 1FileTool — drop an MP4, MOV, AVI, MKV or WebM and it re-encodes to a smaller file on your Mac, never uploading. The compressor outputs H.264 video with AAC audio (or VP8/Opus for WebM) so the result plays anywhere.

Protect your originals first

Replace source is ON by default: the output overwrites the original file and no backup is kept. Before following along, open Settings › General and turn Replace source off, or pick a separate output folder.

Run it

  1. Open Video Tools › Compress (tool page).
  2. Drop a video or a folder of them.
  3. Pick a Quality level — Low, Medium or High. The control reads "Lower quality re-encodes faster and smaller."
  4. Run it and read the result card — per-file size before and after, plus the total saved.
Low, Medium and High map to H.264 CRF levels — lower quality means a smaller file.

The finished file is written as compressed_<name>.<ext> in your output location, keeping the original container format.

What the levels actually change

The compressor re-encodes the video stream to H.264 (libx264, medium preset) with CRF rate control — the dial inside x264 that trades quality against size. Medium is the default and the right starting point; drop to Low for quick shares, keep High for anything you want to archive. Audio is re-encoded to AAC alongside (WebM gets Opus audio and VP8 video instead, staying a valid .webm).

Compression is one of the slower tools — it rewrites every frame. A long 4K file takes a while; the run is cancellable and batch progress shows per file.

What compression can't fix

  • A video that's already heavily compressed shrinks little — there's a floor to how far H.264 can go without visible loss.
  • Trimming a clip shortens it more than compressing it — see Trim Video or Video to GIF if the goal is a shareable clip.
  • Change Bitrate (tool page) targets an exact bitrate if you need a hard size ceiling rather than a quality level.

Tools used

Keep the next file job off the internet.

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