Your files stay on your Mac.
Converting AVCHD MTS to AAC pulls the audio track out of your camcorder clips and saves it as a standalone AAC file — the video stream is discarded. You set the quality level before conversion, so you control how much of the original audio detail is preserved. Convertessa runs entirely on your Mac; footage never touches a server.
Drag one clip or an entire folder of MTS footage onto Convertessa. The app reads AVCHD MTS files directly — no re-wrapping or intermediate step required.
Choose AAC from the output format list. Because AAC is a lossy format, a quality slider appears — move it to balance file size against audio fidelity.
Click Convert. Convertessa extracts the audio track from each MTS file and writes an AAC file alongside it. Every file stays on your Mac throughout.
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.
Only the audio stream is extracted. The video track is discarded and does not appear in the output AAC file.
Because AAC is a lossy format, Convertessa exposes a quality setting before conversion. In the CLI, pass --quality <value> alongside --to aac. Higher values retain more of the original audio at the cost of a larger file.
Yes. Drop a folder onto Convertessa or point the CLI at a directory with convertessa footage/ --to aac. Every MTS file in the folder is converted in one pass.