Your files stay on your Mac.
Convertessa reads your WebM files and re-encodes them as MPEG video — the format expected by legacy players, DVD authoring tools, and broadcast pipelines. Quality is yours to set; the app never imposes a default. Every conversion runs locally, so files never leave your Mac.
Drag a single WebM file or an entire folder onto Convertessa. The app queues everything and processes it in one pass.
Choose MPEG from the output format list. Use the quality slider to balance file size against playback fidelity — available because MPEG is a lossy format.
Click Convert. Convertessa re-encodes each file on your Mac — no upload, no server round-trip — and saves the MPEG files alongside the originals.
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. Convertessa converts entirely on your Mac. Your files never leave your machine.
Yes. Drop a folder onto Convertessa and every WebM file inside is queued and converted in a single pass.
Before converting, use the quality slider in Convertessa — or pass --quality on the command line. Higher quality produces larger files; lower quality produces smaller ones.