Your files stay on your Mac.
Convertessa reads each Windows Media file and writes a Matroska MKV container around the same video and audio streams on your Mac. You choose the output quality before converting, and every file stays local — nothing is uploaded.
Drag one WMV file or an entire folder into Convertessa. Batch mode handles as many files as you need in a single pass.
Pick Matroska MKV from the output list, then set quality to control output fidelity.
Click Convert. Convertessa writes your MKV files into the output folder — resolution is preserved and no metadata travels off 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.
No. Convertessa preserves the original resolution when converting Windows Media to Matroska MKV. The set quality control adjusts output fidelity, not the image size.
Yes. Drop a folder onto Convertessa or run convertessa /path/to/folder --to mkv to convert every WMV file inside in one batch.
Never. Convertessa runs entirely offline on your Mac. Your Windows Media files are read and written locally — no data leaves your machine.