In short
- Diametheus is a desktop app for everyday file chores: shrinking PDFs, converting audio and video, finding duplicates and freeing up disk space.
- Its best trick: point it at a folder and it handles every file inside, subfolders included, in one run.
- Everything happens on your computer. Nothing gets uploaded.
- Free for as long as you like, on Mac, Windows and Linux (including ARM).
- It is open to suggestions: tell me what it should do next.
Why I built it
Diametheus was born out of personal frustration. Every time I needed to do something simple, like shrinking a PDF before emailing it, making a video small enough to share, or converting a recording, I ended up with two bad options.
Option one: upload my files to some random website, wait, download the result, and hope nobody kept a copy. Fine for a meme. Not fine for a contract, a client report or family videos.
Option two: the command line. The tools that do the real work (FFmpeg, qpdf and friends) are brilliant, but I don't want to look up the right flags every time I need to shrink a PDF.
So I built the app I wanted: the power of those tools behind three calm steps. Pick your files, choose the result you want, check the summary, run.
Point it at a folder. It does the rest.
This is the part I use the most, and the main reason I'd ask you to try it.
File chores rarely come one file at a time. It's the folder of scanned documents for your accountant, the clips from a trip, the backup folder full of copies of copies.
In every Diametheus tool you can pick a folder instead of a file. Diametheus then:
- finds every file the tool can work with, subfolders included, and leaves the rest alone
- shows you a summary before anything runs
- works through the whole batch in one go, with progress as it goes
- saves new copies next to the originals (like Report-compressed.pdf), so your originals stay untouched
In one demo run, a "Client Reports" folder with 14 PDFs, two of them tucked away in an "Archive" subfolder, goes from 36 MB to 2.9 MB in a single run (92% smaller). A folder of 4 phone videos goes from 122 MB to 15 MB. Same three steps as a single file.
It works for edits too: trim, fade or normalize a whole folder of recordings, or resize, rotate or watermark a batch of clips, all with the same settings.
What else it does
- PDF: make smaller, combine PDFs and images, split, lock or unlock
- Audio: convert, plus trim, fade, normalize, adjust volume, remove silence, change speed and merge
- Video: convert, combine clips, make a video from audio, plus trim, crop, resize, rotate, change speed, watermark, captions, titles, background music, stabilize and fade
- Media: save media from links
- Your disk: find duplicate files (you review every group before anything is removed), clear temporary files and caches, and spot the large files and folders filling your disk
Your files stay on your computer
Diametheus is a desktop app, so the work happens on your machine. It never uploads your files, and there's no analytics or usage tracking. It only goes online to fetch its helper tools on first launch, to check for updates, to activate a license, or to download the links you give it.
Mac, Windows and Linux
- macOS 12 or later on Apple silicon (M1 or later)
- Windows 10 or 11 on Intel, AMD or ARM
- Linux on Intel, AMD or ARM: .deb, .rpm and AppImage, plus an Arch package
Intel Macs aren't supported.
Free for as long as you like
Every tool works from the first run, with no time limit and nothing locked. After 20 completed jobs, Diametheus shows a short reminder every so often. Dismiss it and keep working. A one-time license removes the reminder. Essential includes updates for one year after purchase. Pro includes updates for as long as active development continues. A personal Essential license is $40 at the early-supporter price. See pricing. If Diametheus does not earn a place on your computer, keep using it anyway.
What should it do next?
Diametheus does what I needed. I'd love it to do what you need too.
If there's a file chore you still do by hand, or still upload to a website for, tell me. Write in. Suggestions decide what gets built next.