Your files stay on your Mac.
Convertessa reads the audio track inside your MKA file and re-encodes it as MP3, entirely on your Mac. No upload, no cloud dependency — your files never leave the machine. Drop an entire folder to convert in one pass, or set output quality to balance file size and fidelity.
Drag one .mka file or a whole folder onto Convertessa. The app reads every Matroska audio file it finds and queues them for conversion.
Choose MP3 from the output format list. Because MP3 is a lossy format, you can set output quality to control the trade-off between file size and audio fidelity.
Click Convert. Convertessa re-encodes each audio track locally with no upload required. Your MP3 files are ready in seconds.
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.
No. Convertessa converts entirely on your Mac using local processing. Your files never leave your machine.
Yes. MP3 is a lossy format, so Convertessa lets you set output quality before converting. Higher quality produces larger files; lower quality produces smaller ones.
Yes. Drop a folder onto Convertessa or pass a directory path to the CLI with convertessa ./folder --to mp3 and it will convert every Matroska audio file it finds.