Your files stay on your Mac.
Converting an MPEG file to AAC pulls the audio track and re-encodes it as Advanced Audio Coding. The resulting .aac file plays natively on Apple devices, web browsers, and most modern players. Files never leave your Mac — Convertessa runs entirely offline.
Drag one MPEG file or an entire folder into Convertessa. Batch conversion processes every file in one pass.
Pick AAC from the output list. You can also set quality to control the trade-off between file size and audio fidelity.
Click Convert. Convertessa processes everything locally — no upload, no internet connection required.
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. Use the quality slider in the app or pass --quality on the command line. Higher values produce larger files with less compression artefacts.
Yes. Drop a folder onto Convertessa or run convertessa ./folder/ --to aac to batch-convert every MPEG file inside in one pass.