Your files stay on your Mac.
Convertessa re-encodes your QuickTime MOV files into WebM, the open container format supported natively by modern browsers. Set quality to balance visual fidelity against file size. Every step runs on your Mac—no file is ever uploaded.
Drag a single MOV file or an entire folder into Convertessa. You can also add files from the menu. Batch mode processes every MOV in the folder in one pass.
Pick WebM from the output format list. Adjust the quality slider to control the trade-off between file size and visual fidelity—higher values preserve more detail.
Click Convert. Convertessa re-encodes each file locally using your Mac's resources. Nothing is sent to a server; converted files are saved 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 files entirely on your Mac. No file ever leaves the machine, regardless of file size or count.
Yes. Drop a folder into Convertessa or pass a directory path to the CLI and every MOV inside is converted to WebM in one pass.
Higher quality produces sharper video at a larger file size; lower quality shrinks the file with more visible compression. Start at the default and adjust until the result matches your needs.