Your files stay on your Mac.
3GP is the compact video container used by older mobile phones and feature handsets. Converting to MP4 makes those clips readable by every modern player, editor, and platform. Convertessa handles the entire transcode locally — your files never leave your Mac.
Drag a single 3GP clip or an entire folder of mobile videos into Convertessa. Batch mode queues every file in the folder automatically.
Choose MP4 from the output format list. Because MP4 is a lossy format, you can set quality to balance visual fidelity against file size before you convert.
Click Convert. Convertessa encodes every file on your Mac — nothing is uploaded and no internet connection is needed. Finished MP4 files land in the output folder.
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.
MP4 is a lossy format, so re-encoding always involves some quality trade-off. Use the quality slider in Convertessa before converting — higher values preserve more detail at the cost of a larger file.
Yes. Drop a folder onto Convertessa or run convertessa ./folder --to mp4 from the terminal. Every 3GP file in the folder is converted in a single pass.
No. Convertessa runs entirely on your Mac — no upload, no account, no internet connection required. Your files never leave your device.