PPTX to ODP

How to do it

1. Download Asteria and open it. It's free and needs no account.
2. Drop your PPTX files onto its window, or press ⌘O (Ctrl O on Windows) to choose them. Drop as many as you like.
3. Type pptx to odpand pick OpenDocument Presentation. OpenDocument presentation from PowerPoint.
4. The first time, Asteria asks to download LibreOffice, a free add-on from The Document Foundation, under the MPL-2.0 license. It shows the download size before you say yes, and needs no administrator password.
5. Press ⌘↵ (Ctrl ↵ on Windows) to save. The ODP files appear next to the originals, which stay exactly as they were.

What it needs

PPTX to ODP uses LibreOffice, a free program for office documents. Asteria doesn't bundle it. The first time you need it, Asteria offers to download it, checks the download against a pinned checksum, and keeps it in its own folder, where Settings can remove it again. If LibreOffice is already on your computer, Asteria uses that copy.

How it was tested

A real PPTX file was converted on macOS on Apple silicon and Linux, and the ODP that came out was opened and checked with zip package + XML text to make sure it is what it says it is.