Your files stay on your Mac.
Convertessa re-encodes your WebM files into the M4V container that iTunes, Apple TV, and iOS expect — video as H.264, audio as AAC. You control output quality before conversion starts. Every file is processed locally on your Mac; nothing is uploaded.
Drag one WebM file or an entire folder onto Convertessa. All queued files are processed in a single pass.
Choose iTunes M4V from the output format list, then set quality to balance file size against visual fidelity.
Click Convert. Convertessa runs entirely offline — no upload, no account, no internet connection needed.
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.
Yes. Convertessa encodes the output as H.264 video with AAC audio inside the M4V container — exactly what iTunes and Apple TV expect. The file imports directly into your iTunes library without any additional steps.
Yes. Convertessa removes embedded metadata during conversion, so the output M4V contains only the video and audio streams.
Yes. Drop an entire folder onto Convertessa or run convertessa /path/to/folder --to m4v from the terminal. Every WebM file in the folder is queued and converted in one pass.