Your files stay on your Mac.
MKA files wrap audio in the open Matroska container — widely supported but not natively playable on Apple devices or in iTunes. Converting to M4A repackages the audio into MPEG-4 Audio, the format Apple hardware and software expect. Because M4A is a lossy format, you can set the output quality before you convert.
Drag one MKA file or a whole folder onto Convertessa. Files stay on your Mac throughout — nothing is uploaded.
Choose Apple M4A from the output format list. Set quality to taste — higher values preserve more audio detail, lower values keep file sizes small.
Click Convert. Convertessa processes every file locally and saves your M4A 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.
M4A is a lossy format, so re-encoding involves some generation loss. Use the quality slider in Convertessa to control the trade-off between file size and fidelity. If your MKA already contains AAC audio, the loss is minimal at high quality settings.
Yes. Drop a folder onto Convertessa and it processes every MKA file inside. You can also run convertessa ./folder --to m4a from the command line to batch-convert in one step.
No. Convertessa runs entirely offline. Your MKA files are processed locally and never uploaded to any server.