Your files stay on your Mac.
Apple M4A files store audio as AAC — a compressed codec. Converting to WAV decodes that audio to uncompressed PCM, producing a file any DAW, audio editor, or broadcast tool can read without re-encoding. The whole process runs on your Mac; no file is uploaded.
Drag one file or an entire folder into Convertessa. The app reads M4A files encoded with AAC audio at any sample rate or bit depth.
Choose WAV from the output format list. Convertessa decodes the compressed AAC audio to uncompressed PCM, preserving the original sample rate and bit depth.
Click Convert. Each M4A is decoded and written as a standard WAV file. Drop a folder and the whole batch converts in one pass.
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. The conversion faithfully decodes the AAC data already in the M4A to uncompressed PCM. Any loss introduced when the M4A was originally encoded is already baked in — Convertessa cannot reverse that. What you get is an identical-sounding file in an uncompressed container.
WAV stores raw PCM samples with no compression. A typical AAC-encoded M4A is 5–10× smaller than the equivalent WAV. If your DAW or tool requires WAV input, the larger file size is the tradeoff for universal compatibility.
Yes. Drop the folder onto Convertessa or run convertessa /path/to/folder --to wav in the terminal. Every M4A in the folder is converted; other file types are skipped.