Your files stay on your Mac.
Apple M4A files store audio as AAC, a lossy codec. Converting to AIFF unwraps that audio into uncompressed PCM — the format DAWs and professional audio editors on Mac expect. No re-encoding chain, no upload, no round-trip through the cloud.
Drag one M4A file or an entire folder into Convertessa. Files never leave your Mac — all decoding happens locally.
Pick AIFF from the output format list. Convertessa decodes the AAC stream to uncompressed PCM and writes a standard .aiff file.
Click Convert. Your AIFF files appear beside the originals, ready to open in Logic Pro, Pro Tools, or any Mac audio editor.
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 — AIFF is an uncompressed container, but it cannot recover information discarded when the M4A was originally AAC-encoded. You get a lossless copy of whatever audio the M4A holds, with no further generation loss.
Yes. All M4A decoding and AIFF encoding runs locally on your Mac. No file is uploaded, no account is required, and conversion works fully offline.
Yes. Drag the folder into Convertessa or run convertessa ./folder --to aiff from the terminal. Every M4A file in the folder is converted and saved as AIFF.