Your files stay on your Mac.
Convertessa reads your Opus audio and re-encodes it into Apple M4A — the container format expected by iTunes, Apple Music, iPhone, and most Apple apps. You choose the output quality before converting. Nothing is uploaded; the entire conversion runs on your Mac.
Drag one Opus file or an entire folder into Convertessa. Batch mode queues every .opus file at once.
Pick Apple M4A from the output list, then drag the quality slider to match your storage or fidelity target.
Click Convert. Convertessa processes the files locally and writes .m4a files alongside your originals. No upload, no wait.
Images, audio, video, documents, archives and eBooks — all converted natively, right on your Mac.
Pick a format you have — see everything Convertessa can turn it into.
Convert hundreds of files at once with per-type group defaults and individual overrides.
First-class support for HEIC, AVIF and WebP — encode and decode, both ways. Read JPEG XL and a dozen more modern formats too.
Drop files anywhere on the window. Native, instant, and exactly what you’d expect on a Mac.
Dial in compression, resolution and bitrate. Keep originals pristine or shrink for sharing.
Never overwrite a file by accident. Convertessa appends safe suffixes automatically.
Every job is logged locally. Re-run a previous conversion or revisit recent outputs in a click.
Bundle your converted files straight into a single ZIP, TAR or 7z — packaged and ready to share the moment a job finishes.
Right-click any file in Finder and choose Convert. A Quick Action handles it on the spot — no need to open the app first.
Shrink Convertessa to a tidy mini window that tucks into a corner — just a drop zone and a format picker for quick, one-off conversions.
No cloud. No account. No upload. Every conversion happens entirely on-device, using the power already in your Mac. What you convert is nobody’s business but yours.
Script conversions, wire them into your build, or batch a folder from the terminal. The same engine, no GUI required.
Read the full CLI documentation →Shrink Convertessa down to a small, focused window — drop, convert, done, with your recent conversions one click away.
macOS 14+ · Apple Silicon & Intel
New formats, new features, and fixes — every release, on the record.
Yes. M4A is the native audio format for Apple devices and services. Files converted by Convertessa play without extra steps in Apple Music, iPhone, iPad, and QuickTime Player.
Yes. Drop a folder onto Convertessa or run convertessa ./folder/ --to m4a in the terminal. Every .opus file in the folder is converted in one pass.
Yes. Convertessa strips embedded metadata from Opus files during conversion. The resulting M4A files contain no source tags or hidden track information.