Your files stay on your Mac.
Converting a Matroska MKV file to AAC pulls the audio stream out of the video container and writes it as a standalone AAC audio file. The video and subtitle tracks are discarded; only the audio is retained. Set quality to balance fidelity against file size.
Drag one MKV or an entire folder into Convertessa. Files never leave your Mac — no upload, no internet required.
Pick AAC from the output format list. Set quality to control audio fidelity before you convert.
Click Convert. Convertessa extracts and encodes the audio stream; your AAC 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.
Only the audio stream is extracted and encoded. Video, subtitle, and chapter tracks inside the MKV container are not included in the output.
Yes. Drag a folder onto Convertessa or run convertessa /path/to/folder --to aac in the terminal. Every MKV in the folder is converted in one pass.
Use the quality slider before you click Convert. A higher setting produces better fidelity at the cost of a larger file; a lower setting produces a smaller file.