FLV to MP4 Converter
Convert legacy Flash Video files to MP4. Batch-ready, stays in your browser.
Best for rescuing old FLV recordings, screen captures, or Flash-era video archives and making them play on modern devices.
Drop files here
or click to browse · paste from clipboard
Accepts .FLV · Up to 1,000 files
How it works
Drop your files
Drag and drop, click to browse, or paste from clipboard. Up to 1,000 files at once.
Choose settings
Adjust quality, format, and other options to match your needs.
Click Convert
Everything runs in your browser via WebAssembly. FLV to MP4 Converter happens locally — no server involved.
Download
Download files individually or grab all at once as a ZIP.
Frequently asked questions
FLV (Flash Video) is a legacy Adobe format from the 2000s that requires the Adobe Flash Player plugin to play — a plugin discontinued in 2020. Modern browsers, phones, and streaming platforms do not support FLV at all. MP4 with H.264 plays on every device without any plugins.
The conversion re-encodes video to H.264, which involves a slight quality trade-off. At the Better setting (CRF 23) the difference is not visible on typical content. Use Best (CRF 18) if you need the highest fidelity.
No. Conversion runs entirely in your browser using ffmpeg.wasm — a full media engine compiled to WebAssembly. Your video never touches a server.
Yes. Drop as many FLV files as you need. Each converts separately in your browser and the results download as a ZIP. No queue, no upload limit.
No hard limit. The constraint is your device's available RAM. Files under 500 MB convert without issue on most desktops. Very large FLV files may require a machine with sufficient memory.
Yes. ffmpeg.wasm handles video-only FLV files. The output MP4 will contain only the video track, which is valid and playable.