Your files stay on your Mac.
WebM is the open container format built for HTML5 video, pairing VP8 or VP9 video with Vorbis or Opus audio. Converting an .ogv file to WebM produces a stream-ready clip that plays natively in every major browser without a plugin. Convertessa handles the encode locally — your footage never leaves your Mac.
Drag one .ogv file or an entire folder into Convertessa. The app reads the Theora video and Vorbis audio tracks packed inside each Ogg container.
Pick WebM from the output format list. Because WebM uses lossy VP9 compression, you can set quality before converting — higher values preserve more detail, lower values produce smaller files.
Click Convert. Convertessa encodes every file on-device and saves the .webm results alongside the originals. No upload, no account, no waiting on a remote server.
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 runs entirely on your Mac. Your .ogv files are processed locally using your device's own hardware — nothing is uploaded to any server.
Yes. WebM uses lossy VP9 encoding, so Convertessa exposes a quality setting before you convert. Raise it for sharper video; lower it when file size matters more than fine detail.
Yes. Drop a folder into Convertessa and it converts every .ogv file inside it to WebM in a single batch — no need to process clips one by one.