Your files stay on your Mac.
Convertessa reads the audio track from your MKA container and re-encodes it as AAC — the compressed format natively understood by Apple devices, browsers, and streaming platforms. The entire process runs locally on your Mac; your files are never uploaded. Drop a single MKA file or an entire folder and convert everything in one pass.
Drag one or more MKA files into Convertessa, or drop a whole folder to queue every Matroska audio file inside it.
Choose AAC from the output format list. Because AAC is a lossy format, you can also set the quality level before converting to control the balance between file size and fidelity.
Click Convert. Convertessa encodes each file on your Mac and saves the AAC output alongside the 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.
AAC is a lossy format, so some audio data is discarded during encoding. Convertessa lets you set the quality level before converting, giving you direct control over the fidelity-versus-file-size trade-off.
No. Convertessa runs entirely offline on your Mac. Your files are never sent to a server — all conversion happens locally.
Yes. Drop a folder onto Convertessa or run convertessa ./folder --to aac in the terminal to batch-convert every MKA file inside it in one pass.