Your files stay on your Mac.
Convertessa reads the audio stream inside your MKV container and writes it to a FLAC file. The conversion runs entirely on your Mac — no internet connection, no upload. FLAC is lossless, so no audio data is discarded.
Drag one file or an entire folder of MKV files into Convertessa. Batch conversion processes all of them in a single pass.
Select FLAC from the output format list. Convertessa extracts the audio track from each MKV and encodes it to lossless FLAC.
Click Convert. Your FLAC files appear alongside the originals. Nothing is uploaded — the conversion runs locally on your Mac.
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.
No. FLAC is a lossless format, so the audio extracted from your MKV is encoded without any data loss.
Convertessa extracts the primary audio track. Video streams and subtitles are not written to the FLAC output.
Yes. Drop a folder onto Convertessa or use the CLI: convertessa /path/to/folder/ --to flac. Every MKV in the folder is converted in one pass.