Your files stay on your Mac.
Convertessa reads your MPEG audio file and re-encodes it into FLAC, a lossless container that preserves every sample exactly. The process runs entirely on your Mac — no file is ever uploaded anywhere. Whole folders convert in a single pass.
Drag one MPEG file or an entire folder into Convertessa. Every .mpeg file inside the folder is queued automatically.
Choose FLAC from the output format list. FLAC is lossless, so every sample decoded from the source is stored without further degradation.
Click Convert. FLAC files are written alongside your originals. Nothing leaves 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 — and that is expected. MPEG audio is already lossy-compressed, so the original encoding artefacts are retained in the FLAC output. What FLAC guarantees is that no additional quality is lost: every sample decoded from the MPEG is stored bit-for-bit in the FLAC file.
Yes. Drop the folder onto Convertessa and every .mpeg file inside is queued. From the command line, run convertessa /path/to/folder --to flac to process all files in one pass.
No. Convertessa converts entirely on your Mac. Your MPEG files never leave your device.