Your files stay on your Mac.
Converting MP4 to FLAC pulls the audio track out of your video file and encodes it as a lossless FLAC stream. Every audio sample is preserved exactly — FLAC discards nothing. Files never leave your Mac.
Drag one MP4 or an entire folder of MP4 videos into Convertessa. Batch mode processes every file in one pass.
Choose FLAC from the output list. Convertessa will extract the audio track from each video and encode it losslessly.
Click Convert. Convertessa extracts and encodes each audio track locally — no upload, no waiting on a server.
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 every audio sample from the original MP4 is preserved exactly. There is no re-encoding degradation.
Yes. Drop a folder onto Convertessa or run convertessa /path/to/folder --to flac in the terminal to batch-convert every MP4 inside.
Yes. Convertessa runs entirely on your Mac. No files are uploaded and no internet connection is required at any point.