Your files stay on your Mac.
Convertessa reads the audio track inside an MKA container and writes it as a standalone FLAC file. The Matroska wrapper is removed and the audio is encoded to lossless FLAC. Every file is processed on your Mac — nothing is uploaded.
Drag one or more .mka files into Convertessa, or drop a whole folder to queue a batch.
Choose FLAC from the output format list. Convertessa targets each audio track for lossless FLAC output.
Click Convert. Convertessa processes every file locally and saves the resulting FLAC files alongside the originals.
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.
FLAC is a lossless format, so no additional quality is lost during the encode step. If the source MKA contained a lossy codec such as AAC, the existing lossy data is preserved as-is inside the FLAC container.
Yes. Drop a folder onto Convertessa or run convertessa ./folder --to flac in Terminal to convert every MKA file in the directory in one pass.