Filenary

FLV to MP4 Converter

Convert Flash video files to MPEG-4 video right in your browser — free, private and with no size limit.

Drop your file here

or click to browse

Choose File

On first use, a ~30 MB conversion engine is downloaded to your browser (one time only).

This file is processed in your browser and never uploaded to a server.

How to convert FLV to MP4

  1. 1Drop your FLV file into the box above, or click to choose it from your device.
  2. 2Click Convert. The conversion runs locally in your browser — nothing is uploaded.
  3. 3Download your new MP4 file as soon as it's ready.

Why convert FLV to MP4?

FLV needs Flash, which no longer exists, so most devices can't play it. MP4 plays on every phone, computer, TV and social media platform.

Why people make this conversion

FLV powered early YouTube and Flash-era screen recordings. Flash died in 2020 — MP4 is where those archives need to live now.

What is FLV?

FLV is the video format of the discontinued Adobe Flash Player, found in old web video downloads.

  • MIME type: video/x-flv
  • Developed by: Adobe, released 2003
  • Powered the first versions of YouTube (2005–2008)
  • Flash Player died in December 2020, so FLV needs converting

What is MP4?

MP4 is the most compatible video format, using H.264 video and AAC audio. It plays on every phone, browser, TV and social network.

  • MIME type: video/mp4
  • Standardized: 2001 (MPEG-4 Part 14)
  • Usual codecs: H.264 or H.265 video plus AAC audio
  • The universal container: phones, TVs and editors all accept it

Frequently asked questions

Is this FLV to MP4 converter free?
Yes, it's completely free with no sign-up, no watermark and no daily limits.
Are my FLV files uploaded to a server?
No. The conversion happens entirely inside your browser, so your files never leave your device.
Is there a file size limit?
Filenary sets no limit — even files over 1 GB work. The only practical limit is your device's memory.
Will converting FLV to MP4 reduce the quality?
MP4 uses lossy compression, so the file becomes smaller with a small, usually invisible, loss of detail. Settings are tuned to keep the result sharp.
Can I convert several FLV files at once?
This converter handles one file at a time. When it's done, click Start over to convert the next FLV file.
Does it work on iPhone, Android, Mac and Windows?
Yes. It runs in any modern browser — Chrome, Safari, Edge or Firefox — on phones, tablets and computers, with nothing to install.

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Add this tool to your website

Copy the code below and paste it into any page. It's free, needs no sign-up, and files are processed in your visitors' own browsers.