Your files stay on your Mac.
Convertessa reads your AIFF audio and encodes it into the Matroska container (.mka). You set the quality level to trade file size against fidelity. The entire conversion runs on your Mac — no file ever leaves your machine.
Drag one .aiff file or a whole folder into Convertessa. It queues every file in the folder for conversion in a single pass.
Choose Matroska from the output format list, then set quality to control the balance between file size and audio fidelity.
Click Convert. Convertessa writes your .mka files locally beside your originals — 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.
It depends on the quality setting you choose. Matroska holds lossy-encoded audio, so lower quality values trade fidelity for smaller files. Set quality to a higher value to preserve more of the original AIFF detail.
No. Convertessa runs entirely offline on your Mac. Your AIFF files are read locally and the resulting .mka files are written locally — nothing is transmitted over the network.
Yes. Drop a folder onto Convertessa and it converts every .aiff file inside in one pass. From the command line: convertessa /path/to/folder --to mka.