Your files stay on your Mac.
3GP is a mobile video container that bundles a video stream with an audio track. Convertessa reads the audio from each 3GP file and re-encodes it as Opus — an open, royalty-free codec built for speech and music at low bitrates. The video stream is discarded; only the audio is written to the output file.
Drag one file or an entire folder of 3GP clips onto Convertessa. The app reads every file locally — nothing is uploaded.
Pick Opus from the output format list. Set quality to taste: because Opus is a lossy codec, a higher setting preserves more detail at the cost of a larger file.
Click Convert. Convertessa processes each file in turn and saves the Opus output alongside the originals, leaving the 3GP source files untouched.
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. Opus is an audio-only format, so Convertessa extracts the audio track from the 3GP container and discards the video stream. The source 3GP file is left unchanged.
Yes. Because Opus is a lossy codec, Convertessa lets you set quality before converting. A higher setting produces better-sounding audio with a larger file; a lower setting shrinks the file at some cost to fidelity.
Yes. Drop a folder onto Convertessa and it converts every 3GP file inside. From the command line, run convertessa ./folder/ --to opus to batch-process an entire directory.