Your files stay on your Mac.
Convertessa reads the audio stream from your MPEG files and writes each one as a Matroska Audio (MKA) file — entirely on your Mac, nothing uploaded. You can process a single clip or a whole folder in one pass, and set the output quality before converting.
Drag one MPEG file or an entire folder into Convertessa. The app reads the audio stream directly from each file without uploading anything.
Pick Matroska (MKA) from the output list. Use the quality slider to set the output quality level before you start.
Click Convert. Convertessa extracts the audio track from each MPEG and saves it as an MKA file alongside the original. Batch jobs finish in a single pass.
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.
When you leave the quality setting at its default, Convertessa copies the audio stream as-is — no re-encode, no quality loss. Adjust the quality slider only if you want to explicitly re-encode at a different level.
Yes. Run convertessa /path/to/folder/ --to mka and Convertessa converts every MPEG file in that folder in one pass, saving each MKA alongside the original.
Never. Convertessa runs entirely offline — your files are read and written locally and are never sent to any server.