Your files stay on your Mac.
WebM is a video container — Convertessa pulls the audio track and writes it out as WavPack, a lossless format that compresses without discarding any data. The conversion runs entirely on your Mac; no file is ever uploaded. Drop a single clip or point the CLI at a whole folder.
Drag one WebM file or an entire folder into Convertessa. Every file in the folder is queued automatically.
Choose WavPack from the output format list. Because WavPack is lossless, there is nothing else to configure.
Click Convert. Convertessa processes each file locally and writes a .wv file alongside the original. 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.
If the WebM's audio track is already lossless (e.g. PCM), WavPack preserves it exactly. If the source uses a lossy codec such as Vorbis or Opus, WavPack encodes whatever data is present without adding further loss — it cannot recover detail removed during the original encode.
Yes. Drop a folder onto Convertessa or run convertessa ./folder/ --to wv and every WebM file in that directory is converted in one pass.
No. Convertessa converts everything locally on your Mac. No file, filename, or metadata is sent to any server.