Convertessa

Convert Flash to MPEG. Offline.

Your files stay on your Mac.

Get the app
1,100+ conversion combinations ›_Command-line included
Convertessa app window showing the format catalog and drop area
What it does

From Flash Video to MPEG on Your Mac

Flash Video (FLV) is tied to the Adobe Flash runtime, which modern browsers and operating systems no longer include. MPEG is a widely supported video format that plays natively on virtually every device and media player. Convertessa reads your FLV files and writes them out as MPEG — entirely on your Mac, with no upload required.

Flash Converter MPEG Converter Flash to AAC Flash to AC-3
How it works

Three steps. No upload required.

1

Drop your Flash files

Drag one FLV file into Convertessa, or drop an entire folder to batch-convert every Flash Video inside it.

2

Choose MPEG

Choose MPEG from the output format list. Adjust quality to balance file size and visual fidelity before you convert.

3

Convert

Click Convert. Convertessa processes each file locally on your Mac and saves the finished MPEG files alongside your originals.

Format catalog

From everyday files to pro media.

Images, audio, video, documents, archives and eBooks — all converted natively, right on your Mac.

Images

JPEGPNGHEICAVIFWebPTIFFSVGJPEG XL+7 more

Audio

MP3AACFLACWAVOGGOpusAIFF+9 more

Video

MP4MOVMatroskaWebMAVIMPEGAnimated GIF+10 more

Documents

PDFWordMarkdownHTMLPowerPointExcelLaTeX+29 more

Archives

ZIPTAR7-ZipGzipped TARRARISO+2 more

eBooks

EPUBMOBIAZW3FictionBook
Conversion explorer

What do you want to convert?

Pick a format you have — see everything Convertessa can turn it into.

— conversion combinations
I have a
can be converted to
From MP4

Features

Built for real work.

Batch conversion

Convert hundreds of files at once with per-type group defaults and individual overrides.

Modern image formats

First-class support for HEIC, AVIF and WebP — encode and decode, both ways. Read JPEG XL and a dozen more modern formats too.

Drag & drop

Drop files anywhere on the window. Native, instant, and exactly what you’d expect on a Mac.

Quality control

Dial in compression, resolution and bitrate. Keep originals pristine or shrink for sharing.

Collision-safe naming

Never overwrite a file by accident. Convertessa appends safe suffixes automatically.

Conversion history

Every job is logged locally. Re-run a previous conversion or revisit recent outputs in a click.

Archive the output

Bundle your converted files straight into a single ZIP, TAR or 7z — packaged and ready to share the moment a job finishes.

Convert from Finder

Right-click any file in Finder and choose Convert. A Quick Action handles it on the spot — no need to open the app first.

Compact mode

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.

Your files never leave your Mac.

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.

On-device processing Zero telemetry No file uploads
For power users

There’s a command line, too.

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 →
zsh — convertessa
# Convert a single file
$ convertessa input.flv --to mpeg
✓ photo.mpeg · 1.2 MB · 0.4s
 
# Batch a whole folder
$ convertessa ./*.flv --to mpeg -o ~/Exports
✓ 14 files converted · 4.1s
Made to fit

And a compact mode.

Shrink Convertessa down to a small, focused window — drop, convert, done, with your recent conversions one click away.

Convertessa in compact mode — a small window with a drop area and recent conversions
Pricing

One price. Yours for good.

Lifetime license
$19
One-time payment
No subscription. No renewals. Ever.
Get the app
  • 1,000+ conversion combinations
  • Lifetime future updates
  • No account required
  • Unlimited devices

macOS 14+ · Apple Silicon & Intel

Changelog

What’s shipped so far.

New formats, new features, and fixes — every release, on the record.

FAQ

Good questions.

Convertessa is a native macOS app that converts your files between formats — images, audio, video, documents, archives and eBooks — entirely on your Mac. Drop a file in, choose an output, and it’s done. No uploads, no account, no subscription.
Convertessa is an orchestrator. Under the hood it relies on best-in-class open-source engines — FFmpeg for audio & video, Pandoc for documents, libvips for images, LibreOffice for office formats, and Calibre for eBooks. It installs them for you with a click, then calls the right tool, or chain of tools, in the right order for whatever you’re converting. You get one clean native interface instead of a tangle of command-line flags. These binaries aren’t bundled with the app and are never installed without your approval — Convertessa simply calls them in a terminal session on your behalf.
Popular ones include JPEG, PNG, HEIC, WebP and AVIF; MP3, AAC, FLAC and WAV; MP4, MOV and MKV; PDF, DOCX and EPUB; ZIP, TAR and 7z — and many more. See exactly what converts to what in the conversion explorer →
Email us and we’ll add it in an upcoming release. Convertessa’s format coverage grows with what people actually need, so your request genuinely helps shape the app.
Your files? Never. Every conversion happens locally on your Mac. Your files are never uploaded, and nothing you convert is ever sent anywhere. Our Privacy Policy spells out exactly what limited data the app does store.
No analytics, no tracking, no telemetry. Your files and conversions stay entirely on your Mac — nothing you convert is ever sent anywhere. The app periodically checks for software updates in the background; like any web request, that check reveals only standard request metadata (your IP and app/OS version) to our update server — never your files, name, email, or license — and updates are always user-approved. Our Privacy Policy spells out exactly what’s stored — and what isn’t.
Yes. Convertessa is a universal app and runs natively on Intel Macs. It requires macOS 14 or later.
Yes. It’s tuned for Apple Silicon (M-series) and runs natively — fast and energy-efficient. macOS 14 or later.
Yes — your license works on an unlimited number of your own Macs. Buy once and install it everywhere you work.
You get a genuinely useful, private, native Mac app for a single $19 payment — no subscription, ever. And your purchase directly supports a small independent developer and the app’s ongoing updates and new formats.
There’s no separate trial, but every purchase is backed by a 14-day money-back guarantee. If Convertessa isn’t right for you, contact your payment processor within 14 days to request a full refund — no questions asked. You can also email us and we’ll help route it.
Quite possibly — just email us. If you’re a student, run a non-profit, or have another good reason, reach out and we’ll sort you out.
Convertessa was built by Daler Azimov — a developer who needed a fast, private, native file converter for his own work, and decided to make the one he wished existed. Connect on LinkedIn →

Yes. Drop the folder onto Convertessa or pass the folder path to the CLI with convertessa /path/to/folder --to mpeg. Every FLV file inside is converted in one go.

Yes. Because MPEG is a lossy format, Convertessa lets you set quality before converting. Higher quality preserves more detail at the cost of a larger file; lower quality shrinks the file at the cost of some visual fidelity.

No. Convertessa runs entirely offline on your Mac. Your files never leave your machine — there is no upload step and no cloud processing.

We’d love to hear from you. Email us and you’ll get a reply from a real person — the one who made the app.