Your files stay on your Mac.
Convertessa reads the audio stream embedded in your FLV files and rewrites it as WavPack — a lossless format that shrinks file size without discarding a single sample. The conversion runs entirely on your Mac, so no file is ever uploaded or sent to a server. Batch a single clip or an entire folder in one pass.
Drag one FLV file or a whole folder into Convertessa. The app lists every file it finds and shows the detected audio stream for each one.
Pick WavPack from the output format list. Because WavPack is lossless, every bit of the original audio is preserved exactly.
Click Convert. Convertessa extracts each audio stream and writes a WV file alongside the original. Original FLV files are left 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. WavPack is a lossless format, so the decoded audio is bit-for-bit identical to the source stream. No quality is sacrificed during the conversion.
Yes. Convertessa removes embedded metadata from the source file during conversion, giving you a clean WV output.
Yes. Drag a folder into the app or use the CLI batch command (convertessa /path/to/folder --to wv) to process every FLV file in that folder in one pass.